tag:blogger.com,1999:blog-78977515090596235252024-02-07T05:48:23.789-08:00When Europe Was An OceanDiscussion and speculation on the ancient world and its many inhabitants Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.comBlogger24125tag:blogger.com,1999:blog-7897751509059623525.post-56708087609741300412016-10-19T03:39:00.000-07:002017-03-25T06:07:01.017-07:00The Zoologist Who Cried Climate ChangeWhy did the mammoth go extinct? Why are there no longer lions in Europe? Why is the largest predator in Australia a smallish dog? There is a clear and concise explanation for every last one of these extinctions, backed up by a great deal of evidence: In North America, the mammoths and lions disappeared within centuries of humans first arriving, in Europe they lasted until warming temperatures improved conditions for people, and on their last island refugees, such as Wrangel island off the coast of Siberia, they lasted until just 4000 years ago, when finally, people arrived there too. A similar story is seen in Australia. When humans first arrived 50,000 years ago, the native megafauna of the continent immediately collapsed, leaving only a few medium sized marsupials, such as the thylacine, as the biggest predators on the continent. Later, a new wave of people arrived, this time bringing more advanced weapons and, crucially, dogs, resulting in the extinction of all thylacine populations save the one on Tasmania, where dingos the never reached.<br />
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The evidence for this scenario is clear and conclusive, backed up by multiple studies and seen across the world. The unique birds of New Zealand were doing just fine until 800 years ago, when the first Maori arrived and promptly proceeded to wipe nearly all of the flightless and many of the flighted species out. When the Europeans arrived several centuries later, they merely finished the job. The megafauna of South America, once the most biodiverse in the world, died out within centuries of humans arriving, after having endured millions of years of ecological and climatic upheavals with little to no effect. The giant lemurs and fossas of Madagascar were eradicated shortly after the arrival of the first humans 3000 years ago, and the few and tiny populations of elephant birds that had managed to cling on disappeared once again after the coming of the Europeans. Arguably most famous of all recent extinctions is that of the dodo, though what fewer people know is that the dodo shared its island home of Mauritius with a wide variety of odd and endemic species, including giant turtles and multiple other species of flightless birds, all of which were wiped out shortly after people came.<br />
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This does not seem like a complicated issue - quite the opposite in fact. Every time humans arrive on a new landmass, the result has been an immediate wave of extinctions. This is seen across the whole world, and evidence for it is ample. Surely, nobody would be naive or stubborn enough to contest this, right? As we will soon see, the bounds of human incredulity and denial are truly limitless.<br />
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<span style="font-size: x-small;"><i>Raphus cucullatus, the famous dodo. Once abundant across its habitat, it is now, as the saying goes, "dead as a dodo"</i></span></div>
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It is a well known and undeniable fact that the Earth's climate has changed dramatically over the last ten thousand years or so. The end of the ice age resulted in drastic increases in temperature, along with sea level, humidity, precipitation, and pretty much all other natural processes. It is not then surprising that, upon initially discovering that most of the now extinct megafauna died out around the time of these changes, people presumed there to be a connection. It seems so neat, so convenient, a nice and tidy explanation to satisfy scientists and the crowd alike. Even today, it seems completely logical at first glance: Temperatures are cold, mammoths and other polar animals do well - temperatures get hot, mammoths and other polar animals die out. Even for the non-polar animals, such as the lions and ground sloths, the notion that a rapid change in climate was simply too much for them to adapt to is easy to swallow. Thus, for many years, this was the preferred explanation behind the extinction of the past megafauna, and it seemed to make perfect sense. Over time however, the cracks started showing. First and foremost, improved dating methods started revealing that the timing didn't <i>quite </i>match up. The extinction of the Australian megafauna has typically been associated with a spike in aridity, but recent research has shown that this change occurred shortly after the extinctions, thus ruling it out as an explanation. In Europe, the extinctions are divided into two waves - an initial one 50,000 years ago, and another 10,000 years ago. The first wave, in which the european elephants, hippopotamus, and several other large species went extinction, does not appear to coincide with any major change in climate, and the second wave of extinctions don't seem to be confined to any one point in time. Some species, such as the mammoths, die shortly after the peak of the change, others, such as the cave bears, die out before, and yet others again, such as the tarpans and aurochs, suffer local extinctions, but don't actually die out completely until much later. Animals such as the lions are even more odd, dying out around 10,000 years ago, but then <a href="http://wheneuropewasanocean.blogspot.dk/2015/10/big-cats-of-europe-past-and-present.html">suddenly appearing again</a> around 6,000 years ago.</div>
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This is particularly odd if climate change is accepted as the explanation, since the extinctions in North America, similar both in climate and ecology to Europe, occurred pretty much all at the same time, around 11,000 years ago. The inconsistencies continue, as South America undergoes a major extinction event, wiping out nearly all of its megafauna, while Africa, again quite similar in climate and ecology, is virtually untouched. New Zealand, where fossil evidence suggest that multiple species of especially the moa experienced severe range contractions after the end of the ice age, nonetheless doesn't undergo a single extinction until long after the end of the massive changes. When taken as a whole, it starts to become apparent that something is very wrong with the climate change explanation. This is not the end of the problems with it however, as there is one final factor that most people ignore, yet which singlehandedly pretty much renders all of the evidence i just provided unnecessary, as it utterly invalidates the climate change hypothesis: The event we tend to refer to as "The Ice Age", is not actually an ice age. Rather, it is a single glaciation event within a long series of glaciations, collectively referred to under the term "ice age". More specifically, it is the eight glacial cycle in the current ice age, which has now lasted 2.58 million years. What this means is that all of the climatic changes that occurred at the end of the last glacial period have not only happened before, but have happened a total of <i>seven </i>times already. Not only that, but the previous glacials and interglacials have varied wildly in length and severity. Some of the previous glacials lasted far longer than the last one, while others were much shorter. Some were significantly more extreme, while others were milder. Just as an example, the previous cycle before ours included a particularly severe glacial giving way to an especially warm interglacial. In summary, all the species that existed at the end of the last glacial period were already perfectly well adapted to the coming and going of the glacials, having experienced and survived them countless times already. Only one single factor was different this time: Humans. </div>
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<span style="font-size: x-small;"><i>A depiction of typical Alaskan megafauna during the last interglacial, showing Mammuthus primigenius, the woolly mammoth, Mammut americanum, the american mastodon, and Bison latifrons, the long-horned bison. From the American Museum of Natural History</i></span></div>
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Okay, fine, the extinctions were not caused by climate change, enough of that already. How does this relate to the opening premise or the title for that matter? Who is "The Zoologist Who Cried Climate Change"?. Well, despite everything I have just listed, and despite the fact that pretty much every new study that's released serves to vindicate this idea, there is still a disturbingly large amount of people who continue to proclaim climate change as not only the most likely candidate, but in many cases the sole, confirmed cause, as if it were a fact. These people range from layman who are, understandably, ill-informed, to hobbyists and even many working scientists, including, yes, zoologists, though generally not people actually working in the field, for obvious reasons. The reasons for this continued belief are manifold, but generally relate to a sort of collective incredulity at the notion that us little, puny humans could really wipe out that many species. I concede that the idea that a small group of humans arrived to a new continent and then proceeded to wipe out tens of species across populations of millions of individuals is hard to wrap your head around, but all of the evidence that we have points towards it indeed having been the case. It being odd and disturbing does not detract from its reality. </div>
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Perhaps it is easier to understand, when one considers that wiping out a species is not just about butchering every last individual. Humans have a tendency of employing many hunting strategies, some of which are particularly destructive to large animals. For one, we may often target the vulnerable young of a given species, since they are easier to take down. If you're a dedicated K-strategist, meaning a species that relies on intensively caring for a small number of offspring that take a very long time to raise, you generally won't reach sexual maturity for many years, and will pour great amounts of time and energy into raising your young. As you might imagine, this makes K-strategists particularly vulnerable to human depredation, and unfortunately, most megafauna are indeed K-strategists. Another aspect of human hunting that makes us abnormally effective at wiping out species is our habit of altering the environment. In particularly, humans do seem to love employing fire, and especially in Australia, which is a very dry place, it appears that the early Aboriginal's use of fire essentially torched the entire continent, helping transform it from a relatively verdant and lush place to the dry and mostly barren land we know today. Fire is hard to escape, quick to spread, and can be quickly and effectively deployed to wipe out animals you don't like, especially if you have no intention of collecting the body afterwards. Know that a large population of particularly dangerous predators live in that forest? Just set it on fire and it'll sort itself out. Finally, a major aspect of human hunting that most people don't even think about, yet may in fact be the most key to our destructive effects on megafauna, is our predilection towards ranged weaponry. First the spear and then the bow, ranged weapons are incredibly dangerous for large animals, as they quite simply have no way of dealing with them. Even the largest and most imposing mammoth will die if you hit it with just a single well placed spear, which isn't particularly hard when your target is that big. Almost every single animal on the planet is adapted towards defending against mele attacks - teeth, claws, tails. Against a weapon such as a spear or an arrow, they have nothing. </div>
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<span style="font-size: x-small;"><i>Fire has been employed as a tool for managing the land since long before grouse moors, and has always been just as destructive.</i></span></div>
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Ultimately, the persistent belief in climate change as the causal factor does not seem to be exclusively a matter of evidence-based conviction. People want to believe in it, because it offers a simple and, more importantly, guilt-and responsibility-free solution. It's just so very, very convenient, that everything that happened in the past was out of our control and beyond our fault. Touting climate change as the perpetrator also serves to render the extinction of the megafauna as natural, just the way things are. It makes our current, denuded and ecologically devastated world okay, since it's the natural order. At the end of the day, the insistence upon climate change as the cause behind the extinctions, rather than an honest explanation for past events, is today little more than a form of denialism, up there with the deniers of genocides or present day climate change. It is pervasive because it gives people what they want, because it makes them feel good, lets them sleep easier at night by rendering them guilt-free. Fighting such a belief is hard, as one side uses evidence and the other emotions. Sadly, the battle of facts and feelings is often quite one sided, and it seems that educating people in this matter is and will forever be an uphill struggle.</div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com1tag:blogger.com,1999:blog-7897751509059623525.post-56396736578783388982016-06-20T12:29:00.000-07:002017-03-25T04:36:14.856-07:00Where did the wild horse go?Tarpan. Isn't it an evocative word? It brings to mind images of wild horses, untamed by man, of fierce stallions and galloping herds. When it comes to wild horses in Europe, "Tarpan" is the go to term. Unfortunately, it is also one shrouded in controversy, and for one simple reason: nobody really knows what it means. It seems simple enough - the Tarpan is another word for the European wild horse, right? Well... kinda. Sometimes. It is certainly true that the undomesticated horses which roamed Europe in prehistory are commonly referred to as Tarpans, but the problem is that the designation is not exclusively limited to them - nor necessarily should it be. If Tarpan is a word for the European wild horse, then it should apply to all members of that species, regardless of when they lived. The factor that complicates everything and throws this neat and tidy definition out of the window can be summarized neatly in one word: Interbreeding.<br />
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Europe has been home to domestic horses for a long time, and for the entirety of their time coexisting with their wild relatives, interbreeding has most likely occurred. Now, at first this was not an issue, since the populations of (mostly) pure wild horses were so larger that the genes of a few domestics did not have much of an impact. As time went on however, and the wild horse populations plummeted, this genetic balance was lost. Suddenly there were significantly more domestic horses than wild ones, and in times of war or simply due to accidents, domestics were often abandoned and left to their own devices, resulting in them becoming feral. This is where the boundary between wild horses and domestics becomes incredibly blurred, and where the word Tarpan really starts to grow sketchy. Historical observers from centuries passed were rarely detail-orientated enough to take note of the subtle morphological distinctions that separated wild horses and domestics, so whenever a herd of wild-living horses was spotted, these animals were simply referred to as wild, and sometimes, you guessed it, "Tarpans". This makes it very difficult to ascertain whether any given historical account of wild horses living in an area actually refer to true, undomesticated horses, or simply feral descendants of domestics. To make matters even more complicated, as mentioned before, extensive interbreeding took place, and in the latter years of the wild horse's existence, it is plausible if not almost certain that very nearly all populations of so-called Tarpans were either hybrids or pure domestic animals, with very few pure wild types remaining. <a href="https://upload.wikimedia.org/wikipedia/commons/1/18/Kherson_tarpan.jpg">This</a> is often referred to as the only known picture of a Tarpan, but looking at its morphology, the animal shown is almost certainly either a hybrid or a pure domestic, as it bares very little resemblance to neither the skeletons we have of European wild horses, nor the extant and closely related Przewalski's horses.<br />
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To add one final layer of complexity and doubt to the word "Tarpan", today it is often used to refer to certain "primitive" breeds of domestic horses, particularly the Konik Polski. Koniks are one of several breeds often claimed to be either direct descendants of wild horses, or, in the Konik's case, a deliberate back-breeding attempt that incorporated hybrids of wild and domestic animals, thus resulting in a breed almost identical to the original wild horse. While the Konik is undeniably a sturdy and "wild"-looking breed, its morphology, like that of the animal in the picture claimed to be a Tarpan, and all other modern horse breeds, does not match that of the wild horse. Genetic tests have shown that it is no more closely related to wild horses than any other modern breed, and the story of it being a back-breeding attempt has been demonstrated to be a myth. In reality, the Konik is simply a particularly hardy breed originally used as draft animals in their native Poland, where the breed presumably originated, which just so happens to somewhat resemble the original wild horse. And yet, regardless of everything I just told you, the Konik is still often referred to as a Tarpan, including by organizations such as Rewilding Europe.<br />
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<span style="font-size: x-small;"><i>Pictured: Not Tarpans, but instead a herd of Przewalski's horses, the world's only still extant species of wild horse.</i></span></div>
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How is this whole history of the word "Tarpan" relevant to the question posed in the title of this post, namely where the wild horse went? The answer is that it serves to illustrate just how difficult answering that question is, because it depends entirely on how you even define the word "wild horse" to begin with. Are feral domestics "wild horses"? What about hybrids of domestics and undomesticated animals? Or is the term reserved exclusively for genetically pure specimens of what taxonomists consider "true" wild horses, that is those that have never been domesticated? If the answer is the first of these options, then they never went anywhere. Quite on the contrary, they've drastically increased both in range and abundance over the years, as feral horses are now found on nearly all continents, including ones where horses never originally lived. If the answer is the second of these options, then the water is muddied, and all modern horses technically qualify since they all descend both originally from completely wild horses, and later on from hybrids of domestics and wilds. True 50/50 hybrids probably died out sometime in the 19th century however. If the answer is the last of these options, then "true" wild horses probably mostly disappeared around if not over a thousand years ago, since interbreeding would have meant that nearly all animals, even those that morphologically resembled wild types completely, still possessed some genes from domestics.</div>
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The species concept is known to be an arbitrary and unwieldy notion, and the very concept of a species "hybridizing" with animals that descend from itself and thus technically belong to it just serves to underline this. Personally, I define "true" wild horses as those which shared the wild morphology, or in other words, if it looked like a wild horse, it was a wild horse. The reason for this is simply pragmatic: Ecologically, modern horses seem to function identically to their ancestors, and genetically, as mentioned above, domestic horses descend from wild horses, and thus technically belong to the same species anyway. Some consider domestics subspecies, others as totally distinct species, and yet others as on the verge of qualifying as either, but personally, I don't much care for this debate. The fact of the matter is the the only major factor which seems to have distinguished wild horses from domestics is their appearance, and as such, it is the only one that much concerns me. This definition of "wild horses" is also what I personally refer to as Tarpans, since it allows me to avoid much of the confusion surrounding the word. Conveniently, defining wild horses as I do happens to allow us to put a more precise date on at the very least their functional extinction, namely some time between the 19th and 15th century.</div>
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<span style="font-size: x-small;"><i>Unmanaged horses such as the Koniks in Oostvaardersplassen are "wild" horses, but they are not <b>wild </b>horses.</i></span></div>
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So then, enough semantics. Where <b>did </b>the wild horse go? In the Americas, we quite simply killed them all, but in Europe, which is my focus, the answer is slightly more complicated. In short, we still wiped them out, but unlike in the Americas, where it happened almost instantly after our arrival, in Europe it was a more drawn out process. It would appear that Tarpans were one of those relatively few species that was capable of surviving our initial colonization and adapting to our presence, but incapable of coping with technological advancement and the rise of civilization. Even as late as the Bronze age, true Tarpans still seem to have been widely distributed across Europe, but soon after, when advanced cultures first started to develop in the Mediterranean region, they quickly disappeared from there, and then shortly after in most of western Europe, as the lowlands became increasingly developed. By the middle ages they were restricted to the mountains and deep forests in nearly all parts of Europe where they persisted, save for the still relatively unpopulated parts of Russia and Ukraine, where they continued to inhabit the open steppes and meadowlands that they were adapted to. The only other region where they were still apparently quite successful was in Iberia, where the dry and scarcely populated inland regions provided something of a refuge. Even this did not last however, and by the 16th century they were restricted exclusively to Eastern Europe, namely Poland and the Russian steppe, by the 17th century only Russia, after what appears to have been an intentional extermination campaign wiped them out in Poland, and by the 18th century the Tarpans as I define them appear to have been almost if not wholly extinct. </div>
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This then is the answer as best I can provide it. Eurasian wild horses, and equines in general for that matter, as this also applies to wild asses, were and still are one of those rare groups that succeeded with little difficulty in adapting to the initial arrival of humans, but simply could not cope with the rise of more advanced civilization. Even the wild equines that still persist to this day are all endangered to at least some extent, some critically so, with one of the least endangered species, the Przewalski's horse, only being in this position after having been reduced to just 13 animals and then pulled from the very brink of extinction by an incredibly dedicated effort, today being one of the greatest examples of a conservation success story. Even so, they suffer heavily from inbreeding, as one might expect from an entire species descending from a group of animals smaller than the immediate families of some people. Luckily, equines as a whole are not threatened, and are in fact one of the groups of large animals that has adapted the best to humans. Wild equines in Africa are generally quite well off, and by way of humans, feral descendants of domestic horses and donkeys have been spread all over the world, potentially forming the foundation of a future radiation of equines even more extensive than the one that came before us. </div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-64173235543863045262016-06-01T10:49:00.002-07:002016-06-01T10:49:57.913-07:00Accepting The ConsequencesWe - or most of us at least - live in cultivated, domestic landscapes. The places in which we live are molded and shaped by human action, and what wildness does exist persists where we have allowed it - or failed to notice it. It is upon this backdrop of suburbs and cities, of supermarkets and cornfields, that most conservation must take place. This is not necessarily a good thing, but it is an undeniable fact of reality. Even in the most distant corners of most countries, anthropogenic influences are still ever-present, and there are people trying to make a living. There are spots, some larger and some smaller, where people are mostly absent, but rarely wholly. In the Scottish highlands, shepherds make their living, in the north of Scandinavia, Sami herd reindeer, and in the Balkan mountains, hunters and farmers base their livelihoods off the land. Here in Denmark, while we have several areas of relatively wild and connected landscapes - significantly more than most people realize - these are still generally used by at least some people. Most of our forests are logged, either by the state or private landowners, our meadows are grazed by livestock and bordered by intensively managed agriculture, and even our biggest and wildest places, such as the hinterlands of the Jutlandic west coast, are often used by the military as training areas. Sometimes these human activities are mostly unrelated to and unaffected by whatever conservation may be taking place. Sometimes the human activities may be directly dependent on them, but in most cases this does not hold true, and in all cases, the presence of people must be taken into account.<br />
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I write about this in part because I have recently been reading and listening to a wide variety of perspectives on conservation and nature, and in part due to the influence that a book by the name of Landmarks, written by Robert Macfarlane, has had on me. The book I will return to later, but for now I will focus on these differing perspectives. It is awfully easy to surround yourself in an echo chamber, an environment in which only agreeing opinions are heard, and in which arrogance and negligence often blossoms. I am, as readers of this blog will probably know, a big advocate of rewilding, and the radical forms of it at that. I follow the movement attentively, and generally have much less interest in traditional conservation, as I see it, to put it bluntly, as a failed attempt, in many cases not worth continuing. This is not of course a commonly held opinion, and even rewilding as a whole is still a relatively niche part of conservation, albeit one which is rapidly expanding. When reading about subjects such as rewilding, about reintroductions and habitat restoration, it is easy only to see the sources you agree with, and become distant to all dissenting voices. It is not that you do not know that they're there, that you don't realize there are people who disagree - of course you do, they're the obstacle that must be overcome for conservation to take place. And that's just it. These dissenting voices, these people who disagree, or at the very least take issue with some parts of conservation and rewilding, they are quickly reduced from real, flesh and blood individuals, with their own motives, worries and passions, to nothing but "obstacles", problems that must be overcome for real, true progress to be achieved. </div>
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<span style="font-size: x-small;"><i>A natural area, part of a reserve in fact, nonetheless clearly influenced and surrounded by human activities. Image from <a href="http://www.samlesbury.org.uk/">http://www.samlesbury.org.uk</a></i></span></div>
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<span style="text-align: left;">When the beavers were first reintroduced in Denmark 17 years ago, there was relatively little protest. To this day, most people, even landowners, are generally fine with their presence in the country. Still, there were some who were against their return, and who continue to be, and there are many who are bothered by them, who want them culled and managed, even if they don't want them wiped out. It is important to remember the effects that these activities have on people. While some conservation endeavors, such as designating marine reserves, help pretty much everyone, including the fishermen, this is not always true, far from it. The beavers were a great benefit to this country's nature when they returned, as they have been so many other places, but to the farmers and foresters who had their fields flooded and their trees felled, these benefits were less clear, and relevant. The benefits were to the country as a whole, to its ecology and culture, but to some individuals, the main changes witnessed were, undeniably, negative. </span></div>
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This is not to say that I agree with them, that I want the beavers eradicated or even in any way culled. I don't. The point is that while their return was undoubtedly and overwhelmingly a good thing, all actions have consequences, and we must never forget that. The return of wolves across Europe has resulted in the loss of farmer's livestock, not nearly as many as reported - most of those were caused by stray dogs- but some nonetheless. The resurgence of seals in the North Sea has lead to declines in some fish stocks, and though these are mostly minuscule compared to the effects of overfishing, this has been problematic for some fishermen. These conflicts are typically heavily overstated, and many of the issues could be avoided or alleviated, but the very fact that there is this conflict, that there are problems which now need to be alleviated, which people must spend time and money to sort out, is a consequence of conservation, of rewilding. </div>
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<span style="font-size: x-small;"><i>"Damage" inflicted to a plantation by beavers, though in this case the area was state owned.</i></span></div>
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It is so very, very easy to demonize and antagonize those who stand in our way, who serve as roadblocks to our efforts. What we must always remember is that, with the exception of a few people who are simply misguided - such as the biologists who rejected reintroductions on the basis of comparisons with invasive species - most of those who oppose concepts such as rewilding do so out of personal and often very justified concern. For those who treasure the uplands of Britain as they are today, reforestation projects and the introduction of predators to prevent the extensive overgrazing that is taking place would be a genuine threat to this landscape that they love. To those who are concerned for the safety of their livestock and crops, the return of wolves and large wild herbivores is a wholly valid concern, even if it often is overblown. This does not mean that what these people want is right - I think the benefits of reintroductions and other forms of rewilding far out way the downsides - but it does mean that we must at least realize the consequences of our actions, and temper our gloating when we succeed with the knowledge that, while our work has been predominantly positive, we have hurt some people. </div>
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Returning now to that book, Landmarks, I should probably start out by saying what exactly it's all about. The book centers on the language that we use to describe nature and the landscapes around us, and how so much of the intricate and complex vocabulary that we once used to detail the natural world is now increasingly going lost. What that book really drove home to me, as it recounted the author's travels to remote rural regions across Britain to gather vanishing terms and sayings from those who still remembered them, is how deeply connected many of the shepherds and other people living off the land really are to their environment. Their effects are hugely damaging, yes, and in my opinion fully justify the actions currently being taken to remedy them, but those people have something that so many of us today have lost, even of those who work in conservation - a deep, genuine connection to their environment, built not just of passion but also very much out of need. This may sound odd - surely a connection to nature built from a love of it is better than a more utilitarian one, right? Well, to try and explain my point, allow me to list a few words from the book describing wetlands.</div>
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A <u>Slack</u> is term for a soft or boggy hollow, used in northern England and Scotland.</div>
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To <u>Stoach</u> is an Essex and Sussex word for churning up waterlogged land, the book citing what cattle do in the winter as an example.</div>
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A <u>Fideach</u> is a Gaelic word for a stretch of green salt marsh which is flooded at high tide.</div>
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A <u>Gwern</u> is a Welsh word for an alder marsh.</div>
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A <u>Breunloch</u> is a Gaelic term for a dangerous sinking bog that may appear green and grassy. </div>
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Now, let me contrast this with the sort of terms we in conservation typically use when describing nature. The sum of an areas species is its Biodiversity, the ways in which it happens to benefit humans is its Ecosystem Services, its level of wetness is its Hydration. These are all useful terms, practical when discussing conservation, but they are also, for lack of a better word, hollow, devoid of life and culture. They are the kind of words used by people who are <b>describing</b> nature, rather than people <b>living </b>in it. When we see a branch covered in moss or lichen, we say "it's covered in moss or lichen". When some rural Scots see a branch covered in moss or lichen, they say it's <u>Foggit</u>. What noise does a covey of partridges make when they break from cover? Do they flap or flutter? No, they <u>Zwer</u>. Tons of languages have the word "Biodiversity". In Danish you say Biodiversitet, in Bosnian you say Biodiverziteta. It's all the same word with minor variations, a general term that crosses nations and cultures but has no deeper meaning in any of them, lacking all forms of uniqueness. Everyone says Biodiversity, but nobody else says <u>Stoach</u>.</div>
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Tying all of this together, the point that I am trying to make is that while we may detest the damage being inflicted upon our landscapes by the people living there, such as the shepherds in the British highlands, we always need to remember that the people inflicting said damage are not the villains, and more than that, they actually often have an even deeper appreciation for the land than those seeking to improve and protect it. Many of the inhabitants of the highlands, with their sheep and their cutting and their burning, may be destroying the habitats of countless species and inflicting incredible damage to the soil, but they are doing it for the best reason possible - namely that they think they're protecting a landscape that they love, to which their lives are deeply connected and which has supported their way of life for centuries if not millennia. The dreadfully sad part of the whole situation is that, up until relatively recently, their activities were actively preserving the landscape. It was a barren, denuded landscape, but a mostly stable one, whose (limited) species richness persisted across the ages. Then came industrialization and globalization, and it all ramped up - more deer, more sheep, more burning and more grazing. The world simply doesn't accomodate the landscape they are trying to protect - the sort that results from centuries of persistent levels of burning and grazing. Even if we wanted to preserve this landscape, which admittedly those who support rewilding don't, we wouldn't be able to in this age of "more, more, more". </div>
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How does this relate to the consequences of conservation, more specifically rewilding? The fact of the matter is that we are changing these landscapes, and in a way that has never happened before. The pattern in nearly all parts of Europe up until now has always been one of ecological degradation or stagnation, where biodiversity is either actively falling or remaining the same. This revival of the landscapes, where previously extinct species and habitats return, is something new, and will require that the old ways and cultures either change or die out. The latter will sadly most likely happen on its own anyway, but an assisted murder is murder nonetheless. The best we can hope to do is to ensure that the old cultures adapt to the new conditions that we are implementing, but this will require them to abandon traditions and ways of life that have persisted for many generations, not to mention coping with the annoyance and potential danger of the surging populations of large herbivores and predators. These are the consequences of our actions - the destruction or alteration of things that have lasted for ages. While rewilding may be the beginning of a new era, it is also very much the end of an older one, and that fact must not be lost on us.</div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-89451929488105203092016-01-14T11:20:00.000-08:002016-05-16T01:23:19.434-07:00Rebuilding Australia: How reintroductions and introduced species could help save a continent's wildlifeI am not from Australia, so I have no doubts that whatever I say will be dismissed by at least some people as just the ramblings of an uninformed foreigner. They may be right, but I would like to think that at least some subjects can be mostly, though not entirely, learned from reading and thinking. I have written about Australia <a href="http://wheneuropewasanocean.blogspot.dk/2015/09/alien-species-and-future-ecology-of.html">before</a>, and in fact I have something of a fascination with the continent for a variety of reasons. One is the most obvious; from a wildlife perspective, Australia is unlike any other continent on present day Earth. The marsupial faunas that (used to) dominate there are the last remaining on the planet, after South America's collision with North America essentially ended the <span style="font-family: Times, Times New Roman, serif;">age of marsupials there, and the general cooling of the global climate wiped them out on most c</span>ontinents. In this respect, it offers us something of a look back at earlier times, and gives us a window into the past diversity that marsupials once enjoyed across so much of the world. There is another reason for my fascination with Australia however. It is the only tropical first world country, and certainly the least densely populated one. The great majority of Australia is still wilderness in one form or another. A rich country with magnitudes of uncultivated wilderness and an iconic endemic fauna, that sounds like a great thing, doesn't it? Most of the problems facing wildlife in other tropical countries are at least partly a result of the widespread poverty and corruption in said countries, and while Australia cannot necessarily be completely cleared of the later, it is certainly nowhere near as extreme as in most countries with similar climatic conditions and quantities of wilderness. You would think that the Land Down Under would be an ideal place for nature, a country with a great fauna wealthy enough to protect it. So why is everything going so horribly?<br />
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With 11% of its mammalian fauna extinct within just the last few centuries, it has the highest rate of mammal extinctions in the world. On top of that, 15% of the remaining species are also endangered, with more yet more on the verge of being so. All in all, things are not going well for Australia's mammals. The typical explanation for this is that, as an isolated island continent, Australia's endemics are especially vulnerable to introduced species. It was the foxes, goats, and horses that did it, or so the story goes. In this post I will be arguing against that prevailing idea, and continuing on my previous post on Australia in arguing that invasive species are merely a symptom of a wider problem, and that a few of the introductions may in fact be part of the solution.<br />
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I will spell out my main thesis from the get go. The reason why Australia's animals are being driven extinct at such a rapid rate is that the most important members of the fauna, the megafauna and the keystone species, have both already been mostly wiped out, destabilizing the entire continent's ecosystems and rendering them unable to adapt. In recent years we have learned that many ecosystems function from the top-down instead of bottom-up, meaning that instead of the smaller species functioning as the basis for all larger animals as previously thought, the larger creatures actually exert a greater impact upon the rest of the ecosystem. Megafauna is crucial to biodiversity and ecological processes, and without them the entire rest of the ecosystem becomes fragile, in some cases, like in Europe, collapsing entirely. Australia's animals are often presented in the same way as island endemics - inherently vulnerable creatures that evolved in an isolated environment. This is undeniably the case for most actual island endemics, but the thing is, Australia is not an island. Every single species native to mainland Australia has at some point had to compete with a vast fauna of other animals, completely comparable to that found on all of the other continents. Thus, saying that the natives of Australia were not used to the level of competition exerted by the introduced newcomers such as foxes and cats is just not true, they absolutely are, in fact they evolved in such an environment. But it is also true that foxes and cats are having a huge and negative impact on the native species of Australia. So, how can one reconcile this apparent paradox? Animals are a very diverse bunch, and even if they fill the same niches, their general behavior may still be very different. As an example, compare the thylacine with the grey wolf. Both are(were) medium sized predators with similar bauplans, both fill(ed) essentially the same roles in their given ecosystems as the principle medium sized predators, yet they act(ed) differently. Thylacines were mostly incapable of tackling larger prey, as indicated by their weak jaws, and as such were probably mostly restricted to smaller game, while wolves are major predators of animals several times their weight. In the pristine Australian ecosystems, it seems that the only animals predating on large herbivores were equally large carnivores, while the smaller predators were mostly restricted to equally or smaller prey. </div>
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So, how does this relate to the introduced predators such as foxes? Well, in pristine Australia, there were fox-sided predators aplenty, but they had different behaviors and diets than actual foxes. An example of such a predator is the misleadingly named Tasmanian devil, which once used to range widely across mainland Australia. It shares the same general prey as foxes, but having co-evolved with the other native Australian species, does not cause any major decline in them. In fact, there is strong evidence to suggest that it actively benefits them, and its presence on Tasmania has often been cited as the reason as to why foxes and cats never managed to become established on the island. And this is the crux of the issue. In a complete ecosystem, every niche is already taken. Small predators, medium sized predators, large predators, and all the ranks in between, they're all present. They don't wipe out the other native animals, as otherwise they obviously would not be able to share ecosystems, but what they do seriously affect is introduced competitors. The chance of a large predator being successfully introduced to an ecosystem with all of its trophic levels intact is pretty much nul. This is why Africa is essentially much completely devoid of major invasive species, while areas like Australia are riddled by them. In Australia, pretty much all of the medium sized and large predators have been wiped out. When the Aboriginals first arrived, they exterminated most of the major predators, such as the giant monitors (Megalania), terrestrial crocodiles (Quinkana), and marsupial lions (Thylacoleo). Then came another wave of immigrants several thousand years later, who proceeded to wipe out the thylacine and tasmanian devils on the mainland, but brought with them the dingo. When the Europeans arrived, the dingo was subsequently heavily persecuted to the point of near extinction, and thus we were left with an entire continent virtually without large predators. Nature is adaptive, and when a niche is open, it will be taken. When pretty much every single niche on an entire continent is open, you can be certain you will get invaders. We set the board on which the Foxes, cats, and other introduced species are now playing. Had we not destroyed most of Australia's original fauna, the opportunity for such large scale invasions would never have existed to begin with.</div>
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<span style="font-size: x-small;"><i>Australia's native predators, like this Thylacoleo, have been slowly and progressively wiped out over the years since humans first arrived on the continent. Art by Peter Schouten</i></span></div>
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So what to do? Since we have wiped out most of the native species, and since the introduced ones are already firmly established, how do we reverse this trend? Well, I won't pretend to have the complete answer to that broad a question, and I very much doubt it is possible to completely reverse the downwards trend, at least for all species. I do however see clear ways to mitigate the damage, and to make some actual quantifiable improvements. For one, not all of Australia's predators are extinct. Most are, but some relatively large critters remain, most notably the various monitor lizards, the tiger quoll, and the Tasmanian devil. Many of the monitors have become rare and locally endangered due to the increase of cane toads (Rhinella marina), but experiments are underway to see if they can be taught not to eat the frogs. If they are successful, it could halt their decline, and perhaps even allow them to recolonize previous parts of their range. Tiger quolls are heavily declining throughout most of their range, save for Tasmania, which is also the only place where the Tasmanian devil remains. The latter are not safe there however, as the confined population is being slowly wiped out by devil facial tumor disease, a form of transmissible cancer that is rapidly spreading through the population. The Tasmanian government does not want the devils reintroduced to the mainland, for fear that it might harm tourism, but the moment conservationists care more about a goverment's income than the extinction of a keystone species is the moment they have lost their way. Reintroducing the devil to the mainland is a cause that all Australian conservationists should be fighting for. A large part of the reason the tiger quolls are declining is due to habitat destruction, as they are native to the western coast of the continent, one of Australia's most heavily cultivated and managed regions. </div>
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Tiger quolls and devils are both in trouble, but they are also a potential key to solving many other species problems. Reintroducing the devils to parts of their range from which they were extirpated, and introducing the quolls to parts of Australia we do not currently know if they have ever inhabited, could quite probably help save them, and the many species that depend on native predators. Many parts of northern Australia still have healthy populations of dingos, and if they were supplemented by quolls and devils, that would go a long way towards reestablishing a guild of native predators. That term is of course rather arbitrary, as dingos are not strictly native. They were introduced by humans some 4000 years ago, and may have been part of the reason why the thylacine went extinct on the mainland in the first place. Today however, they are one of the good guys, as evidence suggests that their presence is a major boon to native marsupials, simply for the reason that they control the numbers of foxes, cats, and multiple introduced herbivores. A healthy ecosystem needs larger predators, and while dingos are not themselves that big, like their wolf ancestors, they fill the niches of animals significantly bigger than themselves. Australia will never be completely rid of animals such as foxes, they are here to stay, but the damage that they do could be minimized. In fact, I would argue, if their populations were controlled by healthy numbers of predators and competitors, they could be fully integrated into the continent's ecosystems. Predators of their size are, as mentioned before, not a new thing in Australia, but without anything to hold them back, they overwhelmed the continent's fauna. If incorporated into a larger predatory guild, they may actually be able to coexist with native animals in a sustainable way, though this is obviously something of a pipe dream at the moment. </div>
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<span style="font-size: x-small;"><i>Tiger quolls could be part of the solution to Australia's introduced species problem</i></span></div>
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I will discuss the introduced herbivores too, but I already covered them quite extensively in the previous post, so I will make it relatively quick here. While the introduced predators are the most famous of Australia's "invasives", the majority of introductions have been of herbivores. Horses and donkeys, known locally as Brumbies and Burros respectively, are now common throughout much of the continent. Goats are abundant in the southwestern regions, mostly where dingoes have been exterminated or suppressed, but do not seem to fare particularly well where predation is high. Both rabbits and hares have been introduced, with rabbits having the greater distribution, and many species of deer have been brought over, mainly from Europe, though most are confined to relatively small areas. Perhaps most famous of the introduced herbivores are the camels, which are both numerous and incredibly widely distributed throughout the central deserts and savannahs of the continent. Forming enormous congregations and strongly affecting the floras of the ecosystems they inhabit, they are the target of a serious culling effort. Another species with a large bounty on their heads is the water buffalo, which is present in parts of the northern swamplands. It is undeniable that these species have a major influence on the ecosystems they inhabit, but this is where I make perhaps my largest contention. I don't think the effects of most of these species are negative, at least not inherently. I am not talking from a cultural or ethical perspective here, but rather a completely ecological one. We are not used to Australia having large populations of megafauna, but this is a case of shifting baseline syndrome, where we forget what came before, perceiving recent conditions as normal even if they are anything but. As mentioned earlier in the article, Australia used to be populated by a wide variety of megafauna, and most of these were herbivores. With giant kangaroos (Procoptodon), rhino-sized wombats (Diprotodonts), and completely bizarre animals like the marsupial tapirs (Palorchestes), the continent was home to a rich fauna of large browsers and grazers. These were all wiped out when humans first arrived, 40,000 years ago, but the fauna and flora of the continent has coevolved with them, and it was the absence, not the presence, of large grazers that was abnormal. </div>
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But of course, if a population of herbivores gets too large, it can be damaging. This is the case even with native species, as demonstrated perfectly by the great environmental damage dealt by the overpopulated deer in Britain. Predators are necessary to manage herbivore populations, and this brings us full circle. In order to have a truly healthy ecosystem, all trophic levels need to be present. That means reintroducing locally extinct species, or, if the species is globally extinct, as is the case with most Australian megafauna, bringing in ecological surrogates that fill much the same role as the missing animals. The camels and horses introduced to Australia fit this bill perfectly, and have the potential to reinvigorate what were previously stale and depauperate ecosystems. This is, of course, on the condition that they are controlled by predators. Mega herbivores and apex predators, those are two key roles that have now been brought back to Australia. Instead of wasting money attempting to exterminate the introduced herbivores while simultaneously fighting a futile war against the cats and foxes, we should accept the continent's new megafauna while trying to reintroduce some of the extinct predators. Only by doing this, by fixing the ecosystems top down, can we hope to stabilize the free fall that Australia's wildlife is currently in. Much like in Europe, conservationists in Australia have been have been fighting the wrong enemies and neglecting the right allies. Unlike much of Europe however, Australia has the space to really pull of ecological restoration at an epic scale, if only they want, and that is of course perhaps the most important part of the problem. </div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com1tag:blogger.com,1999:blog-7897751509059623525.post-42918143603403773702016-01-09T15:01:00.001-08:002016-01-14T11:20:49.822-08:00Remembering the past, Letting go of the present, Embracing the futureWe don't like change. That is understandable, from an evolutionary perspective whatever situation we are currently in is obviously one that is keeping us alive, and as a result, any potential deviation could be dangerous. If our environment at present is adequately supplying us with food, water, and all our other basic needs, any changes, even those that could be positive, are still bringing risk where there previously was none. An old saying is "if it ain't broke, don't fix it", and that particular mentality may be more deeply ingrained in us than we tend to realize. However, as with so many other parts of our biology, our way of life has changed so radically in such a short span of time that evolution has not yet had time to catch up, and this "now good, change bad" mentality seems to be a leftover from our hunter-gatherer past, and a dangerous one at that. We no longer live in the relatively stable environment we evolved in - change is constant in the modern world, and so attempting to ensure that present conditions prevail is inevitably futile. On top of this, mirroring the changes we have dealt to our own lifestyles, the influences and alterations we have induced upon the natural world within just a few thousand years are vast, so vast in fact that we almost certainly have yet to even fully grasp the consequences of what we have done. The main reason for this is that nature is slow to react - or rather, we are incredibly quick to act. Typically in nature, even if changes in the environment send a species spiraling towards extinction, it can still take thousands if not millions of years before the last individuals die. Likewise, changes in climate almost always cause drastic shifts in faunal and floral communities, but these shifts are not instantaneous. Plants are long-lived and slow to disperse, and so it is not unusual to find communities of plants growing in places where others could grow as well if not better.<br />
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What I am trying to get at by saying all this is that even though many of our impacts on the environment are already obvious, their repercussions may take hundreds if not thousands of years to fully manifest. In some cases we can already predict future changes even though they have not yet occurred. An example of this would be several of the species of birds living in our farmlands throughout Europe. Today we associate them with this intensively managed landscape, but comparing present populations to past ones, a downward trend quickly becomes obvious. The populations living in farmlands today are not so much adapted to that habitat as they are relics of a time when different conditions prevailed, mainly the ages before intensive agriculture and pesticides. In time, they will die out, unless another change occurs. The significance of this should be obvious, as it means that we need to be very careful when determining what is in fact any given species' ideal habitat. In Denmark the Goldcrest may almost exclusively live in plantations of non-native conifers, yes, but this is probably a result of the destruction of all native pine forests, not an actual preference for conifer plantations, an environment that does not occur naturally, and thus could never be the ancestral habitat of the Goldcrest anyway. In summary, the present is not nearly as stable as many of us seem to think it is, and any attempts to preserve current conditions on a large scale are inevitably doomed to fail. As we will soon see however, this is not necessarily a bad thing.<br />
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<span style="font-size: x-small;"><i>A quintessentially "modern" landscape, but not necessarily an ideal one</i></span></div>
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I am of the firm opinion that the past was, in the vast majority of respects, preferable to the present. Not everything was better in the past, of course not, but of the things we tend to see as modern improvements, most are only really improvements in relation to the recent past, with issues such as hygiene, oppression, and mass violence all only really having become huge problems during the last few thousand years. On top of this, even if we do accept that there have been real and significant social advances in our civilization, the notion that this somehow overrides the massive deterioration of the global biosphere experienced over the last several thousand years seem to me unbelievably arrogant. Extinction is an ongoing problem today, yes, and we hear many articles talking about how we may be approaching the so-called sixth mass extinction in Earth's history. In truth however all of these articles are misleading - the mass extinction is not upcoming, it is already well underway, and has been ongoing for the last 50,000 years. Compared to its pristine state, Earth today is a vastly depleted and depauperate place. Even if we could stop all extinction, all habitat destruction, and all further depletion of animal populations, the world today would still be arguably the most dull and empty time since the early Paleocene, 64 million years ago and in the immediate aftermath of the fifth mass extinction. Indeed, many of the animal communities still persisting today in most parts of the world are characteristic recovery faunas - assemblages of animals that emerge in the aftermath of local or global extinction events. </div>
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Many are still in denial that today is one of the worst periods in history thus far, continuing to vapidly prioritize short term improvements in well-being in already wealthy countries over the long-term decline of the global biosphere. Even of those that do accept that the past was in many ways preferable to the present however, many seem content to do relatively little with what should be a horrific and mobilizing revelation if ever there was one. Indeed, the general sentiment seems to be that yes, the past was better, but it is gone now, and the best we can do is to preserve what we still have, preventing further decline. This is in my opinion so tremendously inane an argument that I can hardly wrap my mind around it, and brings us nicely to the main point of this article - yes, the present is worse than the past, but the future does not also have to be. History is not by necessity a linear progression of worse-to-worse, and by the future, today will be just as much a part of the past as the <a href="http://wheneuropewasanocean.blogspot.dk/2015/10/lands-pristine-europe-during-eemian.html">last interglacial</a> was. By what insane reasoning have we decided that using the depauperate, unstable and actively collapsing ecosystems of the present as a blueprint for the future is a better idea than using the stable, biodiverse and healthy ecosystems of the past? What makes the present somehow more relevant to the future than the past, save for as a "what not to do again next time" reference? And why does the future have to be as dull and depressing a time as the present? The answer is simple: It does not have to be, nor even can it be. As I said, the present ecosystems are unstable and actively collapsing, they will not last and attempting to preserve them in their current state is like trying to prevent a man falling from a thirty-story building from hitting the ground. Once in freefall, you are eventually going to land. Whether on hard bricks or in a life net is not yet determined, but one thing is certain - you won't stay in the air. Either things will get better or they will get worse, but they won't stay the same. In some parts of the world decline and destruction seems inevitably, but in others it does not. Do we want our future to be vibrant and new, or empty and familiar? That choice is ours.</div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-66420011926497523642015-12-18T02:58:00.000-08:002015-12-18T03:01:11.419-08:00A thought experiment in the HighlandsMuch ink has been spilled over the merits and flaws of rewilding. It is a concept which I have come out in support of multiple times before, though I take issue with many of the claims and arguments made by some so-called "rewilders". One of the main points of disagreement between advocates and opponents of rewilding has been as to what impacts simply letting nature reassert itself would have. Some people say that it would be negative, that human activities are necessary for the preservation of our ecosystems, while others say that it is unquestionably a positive, that can only serve to better our wildlife. Both of these positions are of course extremes, and most people lie somewhere in between, but they give a general idea of what the sides are. To actually answer the question is a difficult if not impossible task, as it would depend on a wide variety of factors. Whether reintroductions are considered a necessary part of rewilding, for instance, completely changes what results said process would have. In this post, I will indulge in a thought experiment of sorts, centered on the British highlands: What if all farming along with most other human activity everywhere in the uplands was stopped, and deer numbers were heavily culled and kept at bay. No reintroductions, no direct action aside from the culling, just a complete ceasing of all activities in the highlands. I do not actually advocate this scenario, nor do I find it remotely plausible, but it offers some idea of what the outcome of one extreme form of rewilding would be. As we will eventually see, it also shows why reintroductions are in fact necessary for rewilding and habitat restoration in the long term, and that "grazing bad, trees good" is not always true.<br />
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<span style="font-size: x-small;"><i>The British highlands as they appear today, beautiful but lifeless</i></span></div>
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Already within a few years of farming ceasing, changes are becoming apparent. Almost everywhere in the highlands, vegetation is growing denser, small bushes are replacing monocultures of grass and low shrubs are spreading across the landscape. From the few woodland refugias and lone trees that had persisted, seeds quickly begin being dispersed throughout the surrounding regions. In some places the heather and bracken has grown too dense for the saplings to take root, but in others large swathes of young trees become established. Pioneer species such as birch in particular grow quickly, and within just a few years some are already more than a meter tall. Dense stands of young trees form vast areas of scrub, with some eventually towering over the bushes below. In the wetter peatlands and windswept mountains, trees take longer to become established. Bushes spread, but alpine grassland and meadow flowers quickly become dominant in the highest regions, and reedbeds emerge across many of the wetlands. From a distance, the landscape 5 years on would not have changed much, most of the plants still too low to change the contour of the terrain, but up close it would quickly become apparent that a radical transformation had taken place. Scrub is now the dominant vegetation-type in most of the Highlands, though of what sort varies. In some places, young woodlands are developing, populated by trees non-taller than a couple meters, while in others trees are mostly absent and dense stands of heather and bracken are dominant. </div>
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In the existing woodland relicts, change is taking place at an equal rate. The forest floor is now full of bushes, young trees, flowers, berries and many other plants, as the undergrowth, once suppressed by intensive grazing, now abounds. Many of the older trees are going out as a result of the increased competition, providing an abundance of dead wood. Animals have drastically increased in numbers, as the profusion of food and new habitat provide a myriad of opportunities for many species. In the open areas covering most of the uplands, biodiversity is likewise rising. The increase in bushes and shrubs has meant that animals once restricted to the relict woodlands can now expand their ranges, connecting previously isolated populations. With grouse shooting over, birds of prey rapidly increase in number, likewise increasing the rate of depredation for many small animals, but this is offset by the expansion of sheltering vegetation. Only a few species have yet begun to decline, mainly the ones dependent on open areas of grass, but most of these persist in the alpine grasslands above, albeit with restricted ranges. In the vast majority of cases, 5 years on, biodiversity has skyrocketed</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiT5er16W-HEy-p8T-VFLt-pMhHMzQEVFHy7gX6ir2jjWonsyrytcs8YlOvV5XM1waz6nqKYR_WxyBt3MElEAn37KNCdJwLkI7X7uGD8UXtPHY8zdvAWE2_-kxAjlMHHMIH_rxWmrfHtiVD/s1600/079_360__coireghaidheil_1432734177_standard.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="186" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiT5er16W-HEy-p8T-VFLt-pMhHMzQEVFHy7gX6ir2jjWonsyrytcs8YlOvV5XM1waz6nqKYR_WxyBt3MElEAn37KNCdJwLkI7X7uGD8UXtPHY8zdvAWE2_-kxAjlMHHMIH_rxWmrfHtiVD/s400/079_360__coireghaidheil_1432734177_standard.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>After a few years, much of the highlands would resemble this fenced in area. Image from Trees For Life</i></span></div>
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At this point we jump 25 years forward. This is because of how slowly trees grow in the highlands. It does not take long for them to become established and existing vegetation such as heather and bracken quickly grows, but the harsh winds and lack of shelter makes it difficult for plants to grow taller than shrub-height. By 30 years onwards however, the transformation is very pronounced. Young woodlands now cover the great majority of the highlands, with the saplings planted within the first years after farming now several meters tall. The bracken-heather monocultures of before are beginning to give away to some extent, though the lack of natural disturbance by way of megafauna means that they still remain abnormally abundant. Now that trees of decent height are established throughout most of the highlands, the amount of potential habitat for many species has dramatically increased. Woodland animals have spread across the uplands, and are now at their most abundant in centuries. Once threatened species such as Capercaillie and Wildcats are now very common, and many ones already widespread today have likewise increased in numbers. </div>
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For the sake of this thought experiment, deer have, as I stated earlier, been heavily culled, and presumably still are, as there is no other way to prevent a population explosion in the absence of terrestrial predators. They are however not completely free from depredation, as the resurgent birds of prey, particularly Golden eagles, are now significant predators of young foals. Regardless, their population has increased slightly, despite the continuing culling, as the expansion of woodlands allows for easier hiding, and the increase in food and shelter means a lower mortality rate. Another effect of the increased food supply and shelter has been that many Red deer now reach larger sizes than they did before, and will eventually grow as large as their mainland counterparts. Roe, Fallow and Sika deer have also all benefited, and Roe in particular are now as if not more common than Red deer.</div>
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<span style="font-size: x-small;"><i>The Capercaillie, one of many species that have benefited from the resurgent woods</i></span></div>
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Dead wood, previously a scarcity in the highlands, is now abundant. The harsh conditions of the uplands mean that many trees die each year, ensuring that where the forests expand to, so does the dead wood. These decaying logs and branches provide ample habitat for a multitude of invertebrates, which in turn provide food to many smaller birds. At the same time, the wood acts as shelters for many small reptiles and mammals, along with a place to hibernate. The nutrients released from the rotting wood, along with the fallen leaves and remains of animals, has now begun to build a new layer of soil where once was thin substrate and barren rock, exposed after millennia of overgrazing. In general, the conditions throughout most of the highlands have now changed from moorland to open woodland, with some elements of remaining moor and dense shrub. Heather has begun becoming increasingly rare, as the old plants die off. A pioneer species, adapted to colonize spaces after forest fires, without being continuously burned by people the plants are now giving way to later stages of succession, as would happen in most natural environments. Despite this, heaths still exist in certain areas throughout the highlands, as forest fires are after all a natural occurrence.</div>
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As the trees have sheltered the forest floor from the wind and the newly developed soil has gathered great quantities of moisture, many microclimates have begun to develop throughout the woods, providing even more habitats for niche species. Many areas with habitats suitable to certain species still lack them however, as their refugias were so few and far between before farming stopped that it will take many years for certain smaller creatures to disperse back across the uplands. Looking at the landscape as a whole, it is still very clear that the process of regrowth is ongoing. While trees once again cover most of the highlands, they are generally small and thin, a few decades old at most. It will take many years before these resurgent woods reach adolescence, but this is not necessarily a bad thing, as we will soon see.<br />
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<span style="font-size: x-small;"><i>30 years on, young woodlands such as these would have expanded across most of the highlands, while those surrounding the last forest remnants have begun to mature. Image from Trees For Life</i></span></div>
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60 years on, many of the new forests have finally begun to mature, while those that emerged shortly after the end of farming have become deep woods in their own right, rivaling the old growths of today, though the trees themselves are still far younger and less impressive sights. It is also now that the necessity of herbivore grazing begins to become apparent. In many places, the forests are now becoming increasingly deep, choking out many species dependent on sunlight. Diversity on the forest floor is beginning to decline, and species are once again dying out. A new monoculture is in the early stages of development, as closed canopy forest slowly begins to envelop the highlands. Most species are dependent on cover in order to shelter from the elements and hide from predators or prey, and this is one of the main reasons why biodiversity is so low in the open highlands of today. Likewise however, most of them also require sunlight and open areas. As the canopies begin to close, and the forest floor darkens, many species of plants and animals are forced out of their habitats. Ordinarily, this would not be a bad thing. Change is constant in nature and in a true wilderness, whose landscape was characterized by a mosaic of habitats, these animals and plants could simply move. In the megafauna-depleted highlands however, there is no mosaic, if it is not bog or mountain top, it is closed forest. With nowhere to go, most of these species will eventually die out.</div>
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Forwarding through time, we see this trend continuing. The forest grows ever deeper and darker, the trees older and larger, and the forest floor increasingly less biodiverse. Grouse and other such groundbirds begin to die out, and in time, even species such as the Capercaillie, an animal dependent on woodland which was once dying out due to the lack of it, is now going extinct due to an overabundance of it. Clearings do of course exist, where storms and forest fires have removed stands of trees, but these are small and isolated, islands of light in a sea of darkness, much like how the relict woods once stood as islands of shade and shelter in a sea of open moorland. This trend will and can not be reversed nor prevented without the reintroduction of several species. Without natural predators, herbivore populations would explode without culling, leading to overgrazing, but human culling can never truly maintain a proper balance, and steering on the safe side, ensuring that deer populations were too low to cause overgrazing, would most likely also denude them of any serious ecological impact, preventing them from keeping the woods open. Likewise, deer are primarily browsers of bushes and low hanging branches, and in the absence of grazers, mixed feeders, and larger animals capable of knocking over trees and opening dense stands of shrub, the landscape will invariably develop into a monoculture of dense, dark forest, home to more species than the empty moors yes, but far less then a healthy, truly wild ecosystem. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHkz8hHvD9usOX9ksc1Bkez80DIjBJQVnlNlNHHRKvW3nN_ThJRWosjI-1TphiupSbSTXAuj2o3xZ8oD98xE1kJ_hHAwtddxxaVIoZU0sEOKB3ZmMq-pg9fkGzz-sUpuw5m165xYCPHJRe/s1600/Scottish-wildcat-MS3000TIFF.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="260" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHkz8hHvD9usOX9ksc1Bkez80DIjBJQVnlNlNHHRKvW3nN_ThJRWosjI-1TphiupSbSTXAuj2o3xZ8oD98xE1kJ_hHAwtddxxaVIoZU0sEOKB3ZmMq-pg9fkGzz-sUpuw5m165xYCPHJRe/s400/Scottish-wildcat-MS3000TIFF.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Scottish wildcats, such as this individual here, would be one of the species that benefited the most from a closed canopy monoculture</i></span></div>
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<span style="font-size: large;">In summary, a complete ceasing of all farming in the uplands would still be mostly beneficial, even in the long term. While biodiversity would begin to decline after the forests become sufficiently dark, it would still be richer than what is present today by an order of magnitude. In many places today, reforestation projects similar to what I have outlined here are in fact taking place, albeit at a far smaller scale. Areas are being fenced off, herbivores excluded from entering and those within heavily culled, and nature mainly left to reassert itself. This is a significant step up from merely maintaining the moors and heaths as they are today, and does demonstrably benefit local biodiversity, but is also unnecessarily unambitious. The highlands area vast place, and there is no practical reason why at least some reintroductions should not be plausible. There are of course barriers to this, especially when considering that human activity will obviously never completely cease throughout the highlands; after all, people do still live there, albeit in low numbers. Regardless, it is clear that if the option presents itself, reintroductions are almost universally recommendable. Not only would they help to enrich the landscape culturally, making it a more interesting place, but for any place to be truly wild, its ecosystems must be reassembled top down. Keystone species drive ecological processes, and in their absence, biodiversity will always suffer. </span></div>
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<br />Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-17644331314559650672015-11-27T07:40:00.000-08:002015-11-27T07:40:37.860-08:00Elephants Of Antiquity Elephants, members of the group proboscidea, are beloved by everyone; they are big, charismatic, and essential keystone species throughout their native range, even in the places where they are now extinct. Once one of the most widely distributed groups of large herbivorous mammals on the planet, they are now confined to tropical Asia and Africa, and even then just barely in many places. I have mentioned them before when talking about some of the regions which they once inhabited, but never in great detail. That changes now, and in this post I hope to cover pretty much the entire native range of proboscideans on all continents, focusing mostly on those now extinct. Just to clarify briefly what I mean when I say "native", while the term has no true agreed upon meaning, for the sake of this post I will define it as any animal which is currently or would still have been present in an area, if not for human activity. Another fact that must be mentioned is that the terms "proboscidean" and "elephant" do not mean the same. All elephants are proboscideans, but not all proboscideans are elephants. The proboscidean family tree is typically divided into two main groups, the elephants and the mastodons, which split early on in their history. So, with that settled, let us begin with the two places where elephants are still present.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0aznQg8K5vLlBC8To9BER4d2SnEr-HUdaRZpvmo6zlP9H_uTokdod_w0BdeJ_NcBqgg-6Je77DaCVVBx_pcUF7f9D2aevs9cE-Qrqgf-bdF8Pmm77PcqbWHfs3ROrXd_7ZOOWPBgprC5W/s1600/evolution_of_proboscidea_by_t_pekc.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi0aznQg8K5vLlBC8To9BER4d2SnEr-HUdaRZpvmo6zlP9H_uTokdod_w0BdeJ_NcBqgg-6Je77DaCVVBx_pcUF7f9D2aevs9cE-Qrqgf-bdF8Pmm77PcqbWHfs3ROrXd_7ZOOWPBgprC5W/s400/evolution_of_proboscidea_by_t_pekc.jpg" width="271" /></a></div>
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<span style="font-size: x-small;"><i>Proboscidean cladogram, by Vladimir Nikolov</i></span><br />
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Africa is important in the evolutionary history of proboscideans, as, like with us humans, it is the continent on which they first evolved. When the earliest proboscideans emerged during the late Paleocene, they were comparatively small, hippo-like animals, only vaguely resembling the long-trunked giants we know today. Back then Africa was an island continent, isolated from the rest of the world, allowing for a whole host of unique lifeforms to emerge, the ancestors of elephants among them. From then til now, proboscideans of one group or another have been continually present in Africa, always playing a major role in the ecosystems of the continent. As this post centers on modern proboscideans however, I will not dwell on their evolutionary history for much longer, as that subject deserves a post of its own. Surprisingly however, when it comes to discussing "native" proboscideans, Africa is probably one of the most difficult continents to do so on. The reason for this is that, as mentioned before, it is also the home continent of hominids. For this reason, our ancestors have been present there for far longer than they have anywhere else, making it difficult to determine what, if any, extinctions were caused by humans. For the sake of simplicity, we will limit the definition of "human" to our genus Homo, which gives us around 2 million years to work with. </div>
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Obviously we have the two extant species of elephants on the continent, the African bush elephant (Loxodonta africana) and the African forest elephant (Loxodonta cyclotis). These have been a constant presence throughout human history, but alongside them lived another proboscidean, Deinotherium. Deinotherium was not an elephant, nor was it a mastodon. Instead it was a member of its own family, which diverged even earlier in the proboscidean tree. The tricky thing about Deinotherium is whether it should be counted as a human-caused extinction. It died out during the early Pleistocene, 1 million years ago. This puts its extinction 800,000 years before the rise of our species, but just at around the point where humans were becoming increasingly predatory and advanced. This also roughly coincides with the time when the last sabertooths disappeared from Africa. Was this a climate-related extinction, caused by the beginning of the ice age, or a result of the increasing hunting pressure exerted by our ancestors? To complicate matters further, even if hominids were the main drivers behind the extinction of Deinotherium, does that really count as a "human-caused" extinction? And should an animal that died out 1 million years ago still be considered native? At what point do the actions committed by our ancestors go from artificial to natural? Needless to say, any and all answers to those questions will almost certainly be wholly arbitrary. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg68TCM2k3yjFhEcq8p8jjq2ZOJsL2fUPAOF3U8YW740mrZSW07MoLMZdMcgz0Qjb9Iw_hBDlVtwd894HilLAwNCEHhhZlgnAK7skS-6OuCncrfrDBP0xAkOyJfHrmJB3yLddBU6gvIn_L4/s1600/281016-alexfas01.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="297" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg68TCM2k3yjFhEcq8p8jjq2ZOJsL2fUPAOF3U8YW740mrZSW07MoLMZdMcgz0Qjb9Iw_hBDlVtwd894HilLAwNCEHhhZlgnAK7skS-6OuCncrfrDBP0xAkOyJfHrmJB3yLddBU6gvIn_L4/s400/281016-alexfas01.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Beautiful illustration of a couple Deinotherium, by Zdeněk Burian</i></span></div>
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Moving on to Eurasia, the picture suddenly becomes far clearer. Central Eurasia was home to 3 species of proboscideans, all elephants, namely the Woolly mammoth (Mammuthus primigenius), European elephant (Elephas antiquus), and Asian elephant (Elephas maximus). The Woolly mammoth was distributed all throughout northern Eurasia, its range expanding south during the glacial periods. It likely had a mixed diet, due to both being found in semi-forested regions along with open plains, and as such was probably something of a generalist, much like extant elephants. In particular, the Woolly mammoth is associated with the so-called "mammoth-steppe", a highly biodiverse grassland habitat that once covered much of northern Eurasia. It was maintained by the vast quantities of grazing herbivores present in the past, among them the mammoths. Slightly larger than an African elephant, what that may have been a result of <a href="https://en.wikipedia.org/wiki/Bergmann%27s_rule">Bergmann's rule</a>, adults would have been almost entirely free of depredation, except that is of course by humans. Young mammoths on the other hand would have been highly vulnerable, and there is good reason to think that they often fell prey to the countless lions and hyenas that shared their environments. A particularly interesting fact is that the Woolly mammoth is technically not a prehistoric animal. One small population persisted on the isolated Wrangel island until just 3000 years ago, at which point humans arrived from the mainland and history repeated itself. This means that, had the early ancient Egyptians known where to look, they could actually have met the last of the mammoths. </div>
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The European elephant has already been covered before in some detail <a href="http://wheneuropewasanocean.blogspot.dk/2015/10/lands-pristine-europe-during-eemian.html">here</a>, while the Asian elephant is of course still extant. This is not to say that they are doing particularly well however, and even ignoring the plights they are currently facing in their remaining range, this is in fact a relict distribution, as they were once found throughout nearly all of southern Eurasia, and would have overlapped to some extent with mammoths to the north, and European and African elephants to the west. This leads us to the last part of Eurasia that needs to be covered, Indonesia. Now, Asian elephants are still present in northern Indonesia today on some of the larger islands, but before the arrival of humans, other, more peculiar proboscideans were found throughout the isolated southern parts of the archipelago. These were members of the genus Stegodon, part of the subfamily Stegodontidae, a group of true elephants that branched off from the family's extant representatives during the Miocene. Stegodonts disappeared from mainland Eurasia and Africa during the early Pliocene, but dwarf species persisted on isolated islands in Indonesia until the latest Pleistocene. The youngest of these species lived on Flores, where it shared its habitat with dwarf hominids and Komodo dragons. It would appear to have gone extinct shortly before the arrival of humans, as a result of a massive volcanic eruption that also wiped out the aforementioned dwarf hominids.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQl8sPADWcfAtvwCMAgiYD7U3NHaVvUyg0jbZ57LixZxyX2b9jJQBh-xgmRu22j18I_kVv-HGAOm1-apB7p8ZMgdaGnTzhtfJPlTLtAhbD0syjmLdDW-WxbUrlVsRAvHPnJTp4-LdBa4mG/s1600/Ice_age_fauna_of_northern_Spain_-_Mauricio_Ant%25C3%25B3n.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="193" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQl8sPADWcfAtvwCMAgiYD7U3NHaVvUyg0jbZ57LixZxyX2b9jJQBh-xgmRu22j18I_kVv-HGAOm1-apB7p8ZMgdaGnTzhtfJPlTLtAhbD0syjmLdDW-WxbUrlVsRAvHPnJTp4-LdBa4mG/s400/Ice_age_fauna_of_northern_Spain_-_Mauricio_Ant%25C3%25B3n.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Woolly mammoths and other ice age fauna in the late Pleistocene of Spain</i></span></div>
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This brings us to the Americas. While Africa is indeed the ancestral continent of proboscideans, and Eurasia home to many species, by the late Pleistocene the Americas were home to by far the most extraordinary proboscidean fauna. Like in Eurasia, Woolly mammoths were present in Alaska and Canada, ranging further south during the glaciations, but another species of elephant, the Columbian mammoth (Mammuthus columbi), was more abundant yet, ranging through almost the entirety of North America. At over 4 meters in height, it was significantly larger than the Woolly mammoth, and indeed one of the largest mammoths of all time. The ranges of the two species overlapped in Canada, while the southernmost parts of the Columbian mammoth's range lay in northern Mexico. One particularly interesting thing about Columbian mammoths is that their remains are heavily associated with Clovis artifacts, providing further evidence of the overkill hypothesis. Another significant animal that must be talked about when discussing North American proboscideans is the American mastodon (Mammut americanum). A bulkier, more robust animal, the mastodon was not as tall as its mammoth cousins, and looked quite different from them. While elephants have tall heads held high above the ground, mastodons had lower skulls with sloping foreheads, giving them a highly distinct look. Unlike mammoths which were probably generalists with a mixed diet, evidence suggests that mastodons were strict browsers, mostly restricted to mere densely forested regions.</div>
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South America was quite different in regards to proboscideans. While the mammoths of the northern continent were reminiscent of the Eurasian faunas, the South American assemblage was completely distinct. In place of the mastodons and mammoths were a group of elephants called the gomphotheres. While technically true members of Elephantida, they are about as distant as any member of the group can be. Short-legged with a sloping forehead, they were relatively mastodon-like in appearance. This is not however due to convergent evolution. This smaller, more robust build is almost certainly ancestral to all proboscideans, and it is in fact the elephants that possess a deviant morphology. Though once also common throughout Afroeurasia and North America, they were confined to South America by the mid Pleistocene, at which point their decline seemingly stabilized, and they continued to thrive up until the arrival of humans. The group was represented by two genera when humans arrived, the tropical Stegomastodon and the temperate Cuvieronius. The latter in particular may have survived until just 9,000 years ago in the mountains of Chile, though as usual, some people have claimed to have evidence of gomphotheres surviving much latter. A heavily stylized rune on and ancient temple is claimed by a few to represent a gomphothere, though this is heavily suspect, as the rune is so vague as to plausibly represent pretty much anything. Another bit of purported evidence is the reports of elephants by some early European explorers in South America. This claim is also riddled with problems however, as these could just have been escaped animals brought by other Europeans or miss-identifications of other animals. This hardly matters regardless, as there is no way to even verify these supposed sightings either way. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitl0b9ZeECa4VIZ8RWtxH3ZqEMD_5F5ha793C0sX0zGcrEyaqXWZWGiWKzFDWBzMtxK6LQAzkS7qrJoBXjsi0dZuA5nwPlK7ujKn7LBlOJ_lffidLTAVFPgMpFIHAmxOVpiK4zHjowuY7B/s1600/Cuvieronius.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="208" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEitl0b9ZeECa4VIZ8RWtxH3ZqEMD_5F5ha793C0sX0zGcrEyaqXWZWGiWKzFDWBzMtxK6LQAzkS7qrJoBXjsi0dZuA5nwPlK7ujKn7LBlOJ_lffidLTAVFPgMpFIHAmxOVpiK4zHjowuY7B/s400/Cuvieronius.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>The Gomphothere Cuvieronius, from Wikipedia</i></span></div>
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There is one last major aspect of proboscidean distribution that must be discussed, namely the island endemic dwarfs that were present many places. I mentioned the stegodonts of Indonesia, but dwarf elephants were also present both on the islands of the Mediterranean and the Channel Islands of California. This post has grown long however, and these dwarfs would be most appropriately discussed in their own post. For now, I hope that this has been an interesting look into the past range of elephants and their kin. We tend to heavily associate these animals with their present day relict distribution, but this is an incomplete picture. Elephants were once one of the most successful and diverse groups of large mammals on the planet, represented by numerous different families across dozens of continents. There is a sadness in seeing them reduced to such a meager standing today, but as long as some species remain, so does hope, and the potential remains for them to recolonize parts of their previous range, perhaps with the help of us humans. In some way, while the great diversity of lineages will never be regained, and the mastodons and gomphotheres are gone for good, reintroduction projects of this sort may offer some form of repentance, or at the very least ensure that the animals that did survive will live with us into the future.</div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-60076790174948165512015-11-09T00:54:00.000-08:002015-12-18T02:30:55.723-08:00Exploring the natural land cover of EuropeHow would Europe have looked if we had never come along? This subject has been covered before, specifically as goes the fauna, but today I will be tackling a different side of this, namely how the landscape itself would have looked. Traditionally imagined as a dense, continent-wide closed canopy forest, this view now seems unlikely, but precisely how it looked is difficult to assess, simply due to our lack of clear evidence. Despite this, enough data is available to give us a general picture of roughly how it may have looked, even if a large amount of educated guesses and inferences are required. The importance of discussing this subject must not be understated, as it is absolutely vital to conservation and habitat restoration. As has been covered <a href="http://wheneuropewasanocean.blogspot.dk/2015/09/the-world-that-we-forgot.html">here</a>, trying to protect and restore the wrong habitats can have a devastating effect on wildlife, as demonstrated by the stark decline in many species caused by the intensive management of heaths throughout much of the continent. To understand how best to protect species we must first know what their natural habitats were, and in what conditions they once thrived. In this post, I will be covering the continent in general, but again with a stronger focus on western Europe, as this is where most attempted habitat restoration is currently taking place and where data is most plentiful.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9BLfEekCkgtQmgopIlO7bSzz-bpf81YPaKYiXQuzjVgpNazTqwxXYTuqNMsG5R-UP-n5_6ae8h9yBomLKoxe1ir22oljlQYiPKiUDy_MZ90EayjH8d8zZfhukxANcTFbkXE74GZg3g3ey/s1600/Stu%25C5%25BEica_primeval_forest%252C_Slovakia.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi9BLfEekCkgtQmgopIlO7bSzz-bpf81YPaKYiXQuzjVgpNazTqwxXYTuqNMsG5R-UP-n5_6ae8h9yBomLKoxe1ir22oljlQYiPKiUDy_MZ90EayjH8d8zZfhukxANcTFbkXE74GZg3g3ey/s400/Stu%25C5%25BEica_primeval_forest%252C_Slovakia.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Old-growth beech forest in Slovakia, often but mistakenly used as a model for all pristine European habitats</i></span><br />
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As mentioned above, deep, closed-canopy forest is often cited as the natural land cover in most of Europe, and is also generally the focus of many more modern attempts at habitat restoration. Unfortunately, this is not quite correct. Closed-canopy forests, also known as climax forests, are the peak of forest development. If undisturbed for a sufficient amount of time, vegetation will grow increasingly dense, eventually culminating in a forest with, as the name implies, an almost entirely tight and closed tree canopy. This can be seen in many places throughout the world, including a few in Europe, such as the above picture from Slovakia. The problem with the assumption that this would be the predominant form of vegetation throughout all of Europe is that, as noted above, for a climax forest to develop, it must be almost entirely undisturbed. Today, in remote areas like mountainsides and sparsely populated valleys, these conditions are quite easy to find, but this is due to two primary factors. The first, and most relevant for the majority of Europe, is that even in these seemingly pristine old-growth forests, large herbivores are often almost entirely absent, or at the very least highly diminished in numbers. Since the discovery of the concept of trophic cascades, it has become abundantly clear that animals exert a far greater influence on their habitats than previously thought. In Africa, much of the landscape is covered in open woodland. In many areas this is due to the dry climate, but research has shown that in other places, when elephants and other megafauna decline or disappear, the open woodlands quickly grow denser, and begin to turn to forest. In Europe, when one considers that, had it not been for human hunters, the continent would still be home to animals such as elephants, horses, rhinoceros, etc, it is reasonable to presume that many of the dense forest ecosystems we see today are actually a result of the same process observed in Africa. If the larger herbivores had never disappeared, they would have played a large role in suppressing the development of climax forest, as they do in Africa.</div>
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The second factor contributing to the development of closed canopy forests in areas like Slovakia is terrain. Most, but not all, of the dense primeval forests that exist in Europe today grow in mountainous areas. Part of this is because humans have cleared most of the lowlands for agriculture, but even in our absence, the mountains would still have had a thicker vegetation than the lowlands. The reason for this is actually much the same as the reason why humans have cleared the lowlands - large animals prefer the more easily accessible floodplains and river valleys, where food is more abundant and transport less difficult. If you are an elephant or even a horse, the lowlands are a much easier place to live than the mountains. Even where large animals do live in the mountains, they do so in lesser densities, and are often unable to reach many areas, thus enabling the development of relatively undisturbed forest. The rocky crags and winding canyons found in most mountainous ares are also ideal hunting territory for many predators, further reducing herbivore populations. This is not the case in most of the European lowlands, and as such, the mountains and slopes are most probably not good analogues. </div>
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<span style="font-size: x-small;"><i>Even though dense forest may not be the natural vegetation for most of Europe, mountainous upland regions like the Lake District should still be cloaked in forest</i></span></div>
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This is not to say that relatively dense forests did not exist in lowland Europe, a variety of factors could allow for certain areas to develop closed canopy forests. Wetlands, if dry enough to allow for tree growth, often serve as a barrier to large animals, and can allow for deep forests to develop even in regions with a heavy grazing pressure. Islands in areas such as Denmark and the Netherlands would not be able to support large populations of herbivores, and as such would also have been covered in dense forests. Certain areas may have been home to particularly large populations of predators, and these too would have been more densely vegetated than the surrounding regions. In general however, completely dense, thick forest would not have been the dominant vegetation type in most areas. This is not to say that most of Europe was covered in steppe or open grassland. Note that I have only been using the word "forest" up until now. It may have seemed slightly repetitive, and perhaps you wondered why I did not spice it up with other words such as "woods" or "woodland". Well, the reason for that is that these words are not interchangeable. Woodland merely refers to a habitat in which trees predominate, and can apply to many different landscapes. As an example, a forest is a particularly dense form of woodland, whilst a savanna is an open form of it. </div>
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The majority of Europe would have been covered in woodland, forming something of a gradient between closed forest and open grassland. The term wood-pasture is often used today to describe this terrain, but while certainly apt, it carries connotations of a cultural landscape, shaped by people. For the unmanaged, naturally occurring semi-open landscape, I prefer "megafaunal savanna". Essentially, while most savannas are a result of climate, where conditions are too dry for forest development but wet enough for tree growth, a megafaunal savanna is an open habitat maintained by the titular megafauna instead of any environmental factors. This also makes this type of habitat particularly vulnerable, as it is wholly dependent on the large animals inhabiting it. In Europe, when the megafauna was wiped out, the megafaunal savanna disappeared entirely. It is in some ways the temperate region's equivalent to the mammoth steppe, an unique ecosystem now completely gone.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeruA9JDBN09QmYmyuF07x4H9Yge9HOtY91_p-BDP5Ax-qROu3EHVRWZ9vjUSD0xMcjOtOiiSBFk-FZ8VGHUNRU2IMOaOcmSRQUl7ICDy7cGeLG-JUgsvnkTJGUVUahOzLIZPE6Mjhyphenhyphen1q3/s1600/Copy+of+S%25C3%25A6rl%25C3%25B8se+Overdrev_11_resize.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="302" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjeruA9JDBN09QmYmyuF07x4H9Yge9HOtY91_p-BDP5Ax-qROu3EHVRWZ9vjUSD0xMcjOtOiiSBFk-FZ8VGHUNRU2IMOaOcmSRQUl7ICDy7cGeLG-JUgsvnkTJGUVUahOzLIZPE6Mjhyphenhyphen1q3/s400/Copy+of+S%25C3%25A6rl%25C3%25B8se+Overdrev_11_resize.JPG" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Semi-open woodland, typical of a wood-pasture environment</i></span></div>
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So what would this so-called savanna have looked like? Well, it depends on where you were. In the more hilly and rugged parts of the lowlands, there would be many nooks and crannies inaccessible to most large animals, allowing trees to grow unhindered. As a result, these regions would probably be more densely vegetated, though plenty of light would still reach the ground. On the flip-side, some regions would house particularly large numbers of herbivores for at least some parts of the year, and as a result, these would quite probably have been almost entirely open, forming grasslands similar to those seen in parts of Oostvaardersplassen. A fenced polder, Oostvaardersplassen is quite controversial among many conservationists, mainly because of the doubts surrounding its validity as an analogue for ancient Europe. It is, at least to me, undeniable that the density of herbivores in the reserve is probably higher than it would have been in most parts of Europe. But most does not mean all, and some regions would indeed have attracted especially large populations of animals, as can be seen in many parts of Africa, and for these areas, Oostvaardersplassen is possibly quite a sound analogue. </div>
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The majority of the megafaunal savanna would probably have been more densely wooded than Oostvaardersplassen however, more similar to the wood-pasture in the above picture. Relatively large stretches of open space would have separated more dense clusters of vegetation, with smaller stands of trees and bushes dotted throughout the fields. But how would trees have been abundant if the grazing pressure was so high? It has been observed in many wood-pastures that while grazers do indeed tend to halt natural regeneration, trees have a way around this. Thorny shrubs ward off grazing animals, and often times saplings will take root within these shrubs. Here they are able to grow in safety, eventually becoming larger than the bushes in which they originated, but by then they are large enough to endure the attacks of the grazers and browsers. This phenomenon can in fact be seen in the image above, as many of the bushes shown there are indeed of the thorny variety, and if one looks carefully, trees can be seen emerging from some of them. This same process also occurs on the African savanna, and was almost certainly the most common way in which new stands of trees originated in many parts of ancient Europe. </div>
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<span style="font-size: x-small;"><i>Konik Horses in one of the more densely vegetated parts of Oostvaardersplassen. The environment seen here is probably very similar to parts of the megafaunal savanna</i></span><br />
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There is more to cover regarding the original land cover of Europe, namely the wetland regions, but that is a subject for another post. In summary, in a world without humans, and where the original European megafauna had not been hunted to extinction, the majority of the continent would not be covered in forest, nor would it be covered in open grasslands. Different areas would house different conditions, but in general, semi-open woodland would have covered most of the continent, with areas of increasingly dense or sparse vegetation. Under these conditions, biodiversity would have been incredibly high, with both cover and light dependent species coexisting in one environment, as the varied nature of this so-called megafaunal savanna allowed for animals of many different niches to share the same environment. I believe that it is this habitat which should be viewed as the ideal throughout most of Europe, as it not only best represents the original, non-altered landscape, but is also quite probably the most biodiverse one possible. Only by looking back into the past, and trying to discern just how things were before we came along, can we truly know what to strive towards. It offers necessary perspective, and a point of confidence and relative certainty as we move forward with habitat restoration and rewilding, all things we severely need if we want to succeed in getting nature out of its dire present state. </div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-35138130679271171942015-11-05T11:44:00.001-08:002015-11-09T00:54:44.175-08:00For All To See: Overgrazing apologists and regressive conservation I have talked about the British highlands <a href="http://wheneuropewasanocean.blogspot.dk/2015/09/the-world-that-we-forgot.html">before</a>, discussing its depleted state, and how it came to be this way. In that article I also devoted a substantial quantity of words to how conservationists have, for a long time, been helping preserve this depleted landscape. None of this has radically changed in the few months since I wrote that post, nor is the subject of today any more relevant now than it was then. It is also not any less relevant however. What I will be talking about here is the issue of those conservationists who have not moved on, who still cling to the old and outdated notions of what is and is not good for nature. They are unfortunately still large in number, and often fill some of the most powerful positions in conservation, controlling the majority of nature reserves. Change is coming, but as with all upheavals, there will be resistance, and much of it at that. Still, there is something uncannily disturbing about a conservationist, supposedly bolstered and driven by science, trumpeting blatantly and demonstrably false statements, so heavily contradicted by evidence, much of which they must be aware of, to border on outright lying. This post is both a rebuttal to the arguments made by these people, and also a reflection on just why they are acting the way they are, and how we may perhaps be able to change it in time.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfYNSPr5LAvM3qlEcf8HSKsfg-NCe6d-xCGWcA5YiCthurRqZ54y4-RWqb3M4mIlTQ_GaaB3A4xvLiqjSNTTmiZNq08uQwK-14cLY2Y-VgEWw_OBRE7PK001S57TBggM6H-VhjIUoJrAa2/s1600/rjw_1899.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="265" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgfYNSPr5LAvM3qlEcf8HSKsfg-NCe6d-xCGWcA5YiCthurRqZ54y4-RWqb3M4mIlTQ_GaaB3A4xvLiqjSNTTmiZNq08uQwK-14cLY2Y-VgEWw_OBRE7PK001S57TBggM6H-VhjIUoJrAa2/s400/rjw_1899.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>A picture of the desolate Scottish highlands, one of many in this post, with sheep in the foreground</i></span></div>
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<span style="text-align: left;">While I don't typically reference recent events or news, partly as to not unnecessarily date these posts, and partly because the subject matter is generally from so long ago as to render recent events quite irrelevant, in this case I will be responding in part to </span><a href="http://www.itv.com/news/border/2015-11-05/george-monbiot-on-the-lake-district-i-see-a-wasteland-and-an-ecological-disaster-zone/" style="text-align: left;">this specific article</a><span style="text-align: left;"> from ITV News. The article itself is not the issue here, it does a decent job of remaining relatively neutral. The issue lies with some of the people quoted within it. They serve as good examples of the mindsets and arguments often put forward by what I have termed "overgrazing apologists", people who claim that overgrazing is either benign, or in many cases even beneficial. So, here is the first quote from Richard Leafe, Chief Executive of the Lake District National Park, one of the most frequently criticized parks in Britain, and rightly so.</span></div>
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<span style="font-size: x-small;">"I think George over-exaggerates for effect. He has a point in as far as we could do better in this National Park for wildlife but what George is not very good at is recognising the contributions that have been made towards achieving that by the farming community: most of them are now in agri-environment schemes which encourage them to manage the land for the environment: reducing their sheep numbers, planting trees, allowing shrubby vegetation to grow and all of that is great for wildlife whilst at the same time keeping the industry farming and I think George doesn't give enough recognition for the very valuable work that we as the National Park Authority and the farming community are doing together to make sure that we have both of these things: a fantastic cultural heritage and great wildlife."</span></div>
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This all seems well and good, but the problem here is numbers. While he states that farmers, and the park itself for that matter, are making big steps towards helping the environment, this is just not what we are seeing. Yes, small areas are being allowed to regenerate to a degree, and tree planting is occurring in some places, but the extent of this is incredibly limited. The British highlands are not, as some people seem to believe, a small area with limited potential for wildlife. They are larger than the country of Slovakia, and about the size of the entirety of my home country, Denmark. Combine this with the fact that the highlands are one of the least densely populated areas in Europe, and it quickly becomes clear that, if the farmers and reserve managers truly wanted, Britain could easily be home to one of, if not the largest wildernesses on the continent. Instead, what we are getting is tiny, isolated islands of woodland in a vast sea of artificial tundra, maintained by constant cutting and burning. This is not to deny the efforts of some farmers, for there are indeed those who have made outstanding efforts towards aiding nature, but they are individuals, not representative of the farming community in general. As we will see in the next quote, even of the farmers who think what they are doing is beneficial towards nature, in many cases they are deeply misguided. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1-koc7iQI9I316eiaudreKYHYBMnMjQS3fJS08Ybc_h7-0I1maYyEbrrQU4kTNOyqwhsVfzvuKxf8Gp_oWPklCV8m7rhLCZAcNLXZAGgpdg1mntxhf_zPBB2mYDdvBOoBdG1Gl4a_mDcV/s1600/Glenridding%252C_Cumbria%252C_England_-_June_2009.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="196" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1-koc7iQI9I316eiaudreKYHYBMnMjQS3fJS08Ybc_h7-0I1maYyEbrrQU4kTNOyqwhsVfzvuKxf8Gp_oWPklCV8m7rhLCZAcNLXZAGgpdg1mntxhf_zPBB2mYDdvBOoBdG1Gl4a_mDcV/s400/Glenridding%252C_Cumbria%252C_England_-_June_2009.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>The Lake District, a national park consisting mostly of towns, heath, and plantations</i></span></div>
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Leafe was not however inherently wrong. While I feel he has a great lack of perspective, he at least seems to understand what is and is not good for nature. John Atkinson, a farmer who has been quoted below, evidently does not share this understanding.</div>
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<span style="font-size: x-small;">"Sheep and cattle and stuff have been here for thousands and thousands of years so the ecosystems and biodiversity sand stuff have grown up to live with that. You take that away and you're going to have a very different sort of things and lots of the species that now live here will die off and disappear." </span></div>
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The issue with his statement is, to put it bluntly, that the entirety of it is factually incorrect. While it is true that both sheep and cattle have been present in Britain for thousands of years, they certainly did not have the same impact that they do today. Never has the management and grazing of the land been so intensive, and never has biodiversity been so low. While the majority of the highlands today are barren heath and rough grassland, the extent to which this is the case has not been the same for the last few thousand years. As with biodiversity, wood cover is also at an all-time low, and while grazing and burning has certainly been creating moors for millennia, it was never to this extent. And yet, that is not even the biggest issue with his statement. The fundamental falsehood that he commits is his proclamation that the wildlife in Britain has been adapting to the altered habitats, and are now dependent on them. It is true that many of the species we see today are adapted to moorland, but this is not because they altered their ecology due to the expansion of heather and grassland. Skylarks and Stonechats were always suited to these habitats, the reason why many of the species living in the highlands today seem so well adapted to moors is quite simply that they are the only things capable of surviving there. It is not that the woodland birds evolved to live in the heathland, it is that everything but the heathland birds went extinct due to the destruction of their habitat. On top of all of this, today, most of the dedicated moorland birds are declining too anyway, because of how intensive the management has become. Effectively, the highlands are now so intensively grazed and burned that not even animals adapted to said grazing and burning can survive anymore. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMdb62sC0NNqIwit1kTgZZN_r4hy0ABPJ7sJ7s63SsG2YhdaAitJT0106YgNlpStXBKyGxm3tPZF17CyEtjHn8YFavDuhWY7cDRCCCzy5U3lpxpNdinP6oXBAYwz8U8-bC6d8Oid7RUnzg/s1600/50_asian_experiences_sheep.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="260" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiMdb62sC0NNqIwit1kTgZZN_r4hy0ABPJ7sJ7s63SsG2YhdaAitJT0106YgNlpStXBKyGxm3tPZF17CyEtjHn8YFavDuhWY7cDRCCCzy5U3lpxpNdinP6oXBAYwz8U8-bC6d8Oid7RUnzg/s400/50_asian_experiences_sheep.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Sheep like these are not good for biodiversity, nor have they ever been</i></span></div>
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So why are we seeing this denial of reality? This is not a poorly researched area, the science is out there, and it very clearly shows that the current practices of intensive management are bad for wildlife. It is perhaps understandable why the sheep farmers might deny this, they do after all have a vested interest in promoting their livelihood as beneficial to nature. Less clear is why the conservationists and managers, with seemingly no economic motivations, also often support these pseudoscientific methods. I do however think there is an answer, and a relatively simple one at that: Admitting that everything you have been doing for the last century to protect nature is actually to a large extent responsible for the decline in wildlife you have tried to prevent is not easy, in fact it is quite a horrific reality. To a person who has spent their entire life promoting burning and grazing in the belief that it benefited nature, a revelation like this one may just be so depressing that simply denying it is easier. Whatever the case, one thing is certain: Reality is not on the side of the slash-and-burn advocates. Their methods have been tried, tested, and proven to not only lack a positive impact, but actually be one of the most harmful activities to wildlife imaginable. Facing up to such a reality may be hard, but for the sake of nature and the future of our wildlife, it must be done. </div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com1tag:blogger.com,1999:blog-7897751509059623525.post-8661128404617844102015-10-31T05:41:00.000-07:002015-11-09T00:57:45.641-08:00Lands Pristine: Europe during the Eemian Previously I have spoken about prehistoric Australia in great length, namely <a href="http://wheneuropewasanocean.blogspot.dk/2015/09/alien-species-and-future-ecology-of.html">here</a> and <a href="http://wheneuropewasanocean.blogspot.dk/2015/08/lizard-kings-giant-monitors-of.html">here</a>, and recently wrote an in-depth post about <a href="http://wheneuropewasanocean.blogspot.dk/2015/10/a-world-in-tar-pits-california-before.html">ancient California</a>. Pre-Human Europe however has been something of a neglected subject, despite also being the one I have the greatest interest in. I have mentioned details about it in passing, but now is its time in the limelight.<br />
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When people think of prehistoric Europe, they typically picture the early Holocene, covered <a href="http://wheneuropewasanocean.blogspot.dk/2015/09/the-early-holocene-of-europe-from-11000.html">here</a>, but as that post discusses, the pristine European wilderness was already gone by then. No, to see Europe as it would still have looked today if not for our presence, one must go back to the Eemian, also known as the last interglacial. Spanning from 130,000 to 115,000 years ago, it was the last point in time when the climate resembled todays, but the megafauna had not yet died out. All of the modern species we know today already existed, and at a cursory glance it would have looked quite similar, but the Eemian was to modern Europe what present day southern Africa is to its northern counterpart, an unspoilt, pristine version of the latter, in which the now vanished giants were not just present, but dominated the landscape. In this post I will be covering primarily western Europe, as that is the place with which I am most familiar, and we will explore a Europe quite different from what we know today.<br />
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<span style="font-size: x-small;"><i>Trafalgar Square, 130,000 years ago, by Roman Uchytel</i></span></div>
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To see Eemian Europe would be much like seeing the great nature reserves of Africa, a vast expanse of wilderness, populated by countless animals of all shapes and sizes. The climate was, as mentioned above, similar to that of today, though it fluctuated over the course of the period, but the landscape itself would have been different, at least in the regions covered by ice during the last glacial period. Glaciers shape the landscapes they move across, and countries such as Denmark would have appeared almost entirely different in form, though it is impossible to determine exactly how it looked. Woodlands covered much of the continent, but were less dense than those of today. Large grazers and browsers shaped the landscape, creating what I have informally named a "megafaunal savanna", that is, a savanna shaped not by climate or geography, but by the animals living in it. Elephants and rhinos trampled the vegetation and opened up dense stands of bushes and trees, bison and horses grazed the meadows and grasslands, and Aurochs and deer kept the shrubs and smaller trees in check. Due to these factors, many parts of the continent would have heavily resembled places such as the Serengeti or Kruger national park, and studies in Africa have shown that in many regions, when the large animals are removed, the environment undergoes a rapid change in character, grasslands turning to shrub and woodlands growing darker. </div>
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This is not to say that dense forests did not exist in Eemian Europe. A vast rainforest covered much of the Atlantic seaboard, maintained by the moisture brought in from the sea. Here, colossal trees would have towered above the ground, cloaked in epiphytes such as mosses and vines, while the soil was wet and soft, covered in herbs and bushes. Though similar in climate to the temperate rainforests of the North American western seaboard, it would have been far wetter due to the influence of the Atlantic, giving it a character unlike any other rainforests today. Further inland, other great forests spread across the mountains and wetlands, where large animals had more difficulties reaching, and these would have been similar in nature to the primordial woods still found in places such as Poland and Romania today. </div>
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<span style="font-size: x-small;"><i>Primordial forest in Biogradska Gora, Montenergo</i></span></div>
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In the floodplains and grasslands, great herds of herbivores would have grazed. Tarpans, the European wild horse, would have been one of the most prevalent animals, forming huge congregations resembling those made by zebras today. Aurochs and Bison would have shared their habitat with another bovid few people know used to live in Europe, the Water buffalo. Bison prefer drier environments, and would presumably have stuck to the savanna and woodlands, while Aurochs were more adaptable, capable of surviving in both dry and wet conditions. The Water buffalo were not the only large mammals inhabiting the waterways of ancient Europe however, and they shared their habitats with Hippopotamus. While typically seen as tropical animals today, this is merely a result of their extermination in the entirety of their temperate range. Large animals do not need as much fur for insulation as smaller ones, and equipped with the huge quantities of fat that they possess, hippos were perfectly capable of surviving even in the colder regions of Europe. When Trafalgar square was first being excavated, the workers found hundreds of Hippopotamus bones, indicating the animal's once great abundance. </div>
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Deer were common then as they are today, but would have played a different role in their environments. While Roe deer were probably shy forest dwellers, Red deer, typically also thought of as woodland animals, seem to have been common in open environments too. As indicated by places such as Oostvaardersplassen, when given the option, Red deer will often form large herds in the open grasslands and savannas. There were also deer species now extinct, most prominently of the genus Megaloceros, the largest and most well known species being M. giganteus, often but incorrectly called the Irish elk. Larger than the Alaskan moose, they were huge animals, and also seem to have preferred more open environments. Fallow deer are widely known to have been introduced to western Europe by people, but less well known is the fact that they were actually present throughout all of the continent during the last interglacial. In a way, one could almost view their introduction for the purposes of hunting as a form of unintentional reintroduction. </div>
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<span style="font-size: x-small;"><i>A vast herd of horses in Oostvaardersplassen, Netherlands</i></span></div>
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Largest of the terrestrial animals in Eemian Europe were the elephants and rhinoceros. When most people hear "Elephants in Europe", they think of the Woolly mammoth (Mammuthus primigenius), but the mammoth was a cold adapted species, native to the northernmost parts of Eurasia and North America. They only spread into Europe during the last glacial period, as the climate there came to resemble that of Siberia and Alaska, and would have returned north after the end of the glacial period had Humans not wiped them out first. No, the true European elephant was <b>the </b>European elephant, Elephas antiquus, sometimes also called the Straight-tusked elephant. Similar in size and shape to its close relative, the Asian elephant, it had proportionally longer legs, and more impressive tusks, but was otherwise almost identical in looks and ecology. Commonly found in Pleistocene sediments, it was evidently very abundant, clearly one of the most successful animals of its time. As with elephants in Africa and Asia today, the European elephant was what we call an ecosystem engineer - a species that exerts a greater force upon its environment than the environment does upon it. Actively shaping their surroundings by creating temporary wetlands where they walked and slept, and clearing woodland by toppling trees and crushing bushes, the latter action in particular is fascinating, as trees and shrubs in modern day Europe display a heavy resilience to being bent and broken, an adaptation that African and Asian trees also show. On those continents, this seems to be a defense against elephants, and it is almost certain that the adaptations seen in the European trees exist for the same reason, an echo of the past, and a defense against a now gone foe. </div>
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Again, when most people here "rhinos in Europe", they think of the Woolly rhino (Coelodonta antiquitatis), but as with the Mammoth, these were tundra animals, only moving into Europe temporarily during the glacial periods. The true European rhinos were Merck's rhinoceros and the Narrow-nosed rhinoceros. One was a specialized browser, the other a grazer, resembling the extant White and Black rhinoceroses in ecology respectively. Members of the genus Stephanorhinus, they arrived during the mid Pleistocene and remained there until 40,000 years ago, when Humans hunted them to extinction. During the Eemian, both were widespread, present from Britain to eastern Europe and beyond. As with the elephants, the remains of rhinoceros are common, indicating that the animals were highly abundant. Both were similar in size and appearance to the African rhinos of today, but were in fact more closely related to the various critically endangered species found in Indonesia today. </div>
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<span style="font-size: x-small;"><i>A herd of European elephants, by Charles Knight</i></span></div>
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This brings us to the predators. Eemian Europe was home to an impressive predatory guild, even greater than that of Africa today. Chief among these were the Lions, covered <a href="http://wheneuropewasanocean.blogspot.dk/2015/10/big-cats-of-europe-past-and-present.html">previously</a>, which played much the same role then as they do today where they persist. Slightly larger than modern Lions, they belonged to the same species, and were probably almost completely identical in ecology. They may have shared the roles of top predator with the Scimitar cat (Homotherium), though this species has an odd history in Europe. Abundant until 500,000 years ago, when it suddenly disappeared, recently discovered remains from the North Sea show that it was present in Europe 28,000 years ago. Whether this indicates that the genus was present continuously in Europe all along, but that we merely have not found remains, or that they periodically returned to the continent before going extinct again is unknown. Whatever the case, it can be said with relative confidence that Homotherium may very well have been present in Europe at least briefly during the Eemian, though it is not certain. Other than the Lion and possibly Homotherium, Europe was also home to two other big cats, the Leopard and the Lynx. For more on them, read the article linked above. </div>
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Cats were not however the only predators in Europe, nor did they make up the bulk of the predator guild. Canids in particular were highly diverse during the Eemian, represented by the Grey wolf, Red fox, Golden jackal, and Dhole. Canids, evidently being a very resilient group, experienced only one extinction, the Dhole. It has survived til today in southeast Asia, but is now highly endangered, and a reintroduction scheme may be the only way to save it from extinction. Another apex predator was the Spotted hyena, widely distributed across most of Eurasia all the way up until the beginning of the Holocene. While hyenas widely disliked by the general public, they are impressive animals, adaptable and in many cases better and more efficient hunters than Lions, far from "mere" scavengers, and their presence in Europe attests to this. Lastly in the predator guild are the bears, represented by two species, the extant Brown bear, and the extinct Great bear (Ursus spelaeus), typically referred to as the "Cave bear". Counting all these species together, one can see that Eemian Europe clearly housed a predator guild every bit as diverse as that of Africa, and highly impressive in its own right. </div>
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<span style="font-size: x-small;"><i>Two Dholes playing, from Wikipedia</i></span></div>
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While Europe today is certainly not the richest continent in terms of wildlife, it harbors the memories of a time when it once was. It is crucial to note that while what I have been describing in this post is the Eemian of Europe, almost every single thing said would also apply to a present day Europe where modern Humans had never arrived. Of the species I have listed here, many are extinct, but the blame for each and every one of these extinctions lies solely on us. As the world's remaining wildlife withers and dies in the poor countries where it previously had refuge, it is no longer acceptable for us to sit and watch without taking any considerable action. Nature in Europe has already been reduced to tattered remnants, but just as the present is not the past, nor must it be the future. Wildlife needs a new refuge, somewhere capable of affording its presence, and defending its inhabitants. The future of European conservation is restoration, and in the process of bringing back our own nature, we also have a chance to save the wildlife currently vanishing from the rest of the world. </div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com2tag:blogger.com,1999:blog-7897751509059623525.post-19300679495926426292015-10-30T08:16:00.002-07:002015-11-09T01:03:59.942-08:00A World In The Tar Pits: California before HumansCalifornia is known for many things; Hollywood, Silicon valley, and more recently unprecedented droughts. What it is less known for however, at least to the general public, is the vast diversity of life that once lived there. Located in California lie the La Brea tar pits, which are, as the name suggests, a group of tar pits, that have been trapping animals for the last 40,000 years, giving us an incredibly detailed view into the paleofauna of the region. Perhaps the best site for late Pleistocene animals in the world, it certainly contains some of the most spectacular creatures. From giant ground sloths and saber toothed cats to mammoths and mastodons, prehistoric California had one of the most diverse megafaunal assemblages in the world, far outmatching that of even Africa, both today and in the Pleistocene. In this post we will be travelling back 11,000 years, shortly after the end of the ice age, and right before the arrival of the first humans.<br />
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<span style="font-size: x-small;"><i>Paleoenvironment of La Brea, by Charles Knight. The animals in the foreground are the sabertooth Smilodon, Harlan's ground sloth, and the giant vulture Teratornis. In the background can be seen a herd of Columbian mammoths. </i></span></div>
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The Americas, north and south, had the richest megafaunas in the world. California was in many ways one of the crowning jewels, its fauna impressive even when compared to the rest of the continent. While Europe and southern Asia only have 1 endemic species of elephant each, the Asian elephant (Elephas maximus) and European elephant (Elephas antiquus) respectively, La Brea preserves two Proboscidean genera, the American mastodon <span style="font-family: inherit;">(<span style="line-height: 22.4px;">Mammut americanum), and the Columbian mammoth (Mammuthus columbi). Of these, only the latter was actually a true elephant, while the former belonged to the group mammutidae, an early off-shoot of the elephant lineage. Interestingly, the two had quite different ecologies. While the Columbian mammoth was a mixed grazer and browser, much like the extant elephants, the American mastodon was a specialized browser, and would probably have been less common in the arid conditions of California. As the largest animals in their environment, adults would have been almost entirely free from predation, but their young may have been major prey items of the many carnivores of the time. </span></span><br />
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<span 22.4px="" line-height:="">The second largest animals living in California were the ground sloths. Extant sloths are small and relatively sluggish animals, quite innocuous in appearance and behavior, but their recently extinct relatives were anything but. The largest of the ground sloths were larger than modern day elephants, and while the species found in La Brea were not quite that large, the biggest, Jefferson's ground sloth, was still larger than a rhinceros, and even the smallest, the Shasta ground sloth, was still the size of a Brown bear. They may have filled ecological niches similar to those taken by the aforementioned rhinos in the old world, as the Americas were oddly devoid of any rhinoceros species during the Pleistocene, the last having died out in the late Miocene. Together, the sloths and proboscideans would have been some of the most important keystone species in their habitat, ecosystem engineers capable of exerting great force upon their environments. They would have opened up dense tree stands, but also fertilized the ground and helped spread seeds, resulting in more abundant but disparate woodlands. </span><br />
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<span style="font-size: x-small;"><i>Broad-headed bison, Bison latifrons, by Roman Uchytel</i></span></div>
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While elephants and giant sloths may be particularly impressive, they would not have been the most abundant animals in pre-human California. As in Africa, the bulk of the region's megafauna would have consisted of comparatively smaller grazers, which would have formed great herds and congregations. In many respects, prehistoric California, like most of the ancient world, would have resembled the great wilderlands of Africa in many significant respects. Instead of antelopes, the Americas have pronghorns, which today persist through only a single species, but were represented by 12 different species back in the late Pleistocene. In the place of zebras were 2 separate species of horses, giraffes were replaced by giant camels, wildebeests by bison, and hippos by tapirs. All of these groups still survive today in some regions of the world, but the great diversity of lineages has been lost. While there now is only 1 species of bison in North America, the appropriately named American bison (Bison bison), La Brea preserves 2, the enormous, long-horned Bison latifrons, and the "ancient bison", Bison antiquus, the ancestor of the American Bison, and therefore technically still extant. </div>
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There were 2 species of horses in California, the Mexican horse (Equus conversidens), and the Western horse (Equus occidentalis). Similar in size and shape to extant wild equines, they would probably have lived equally similar lifestyles. As with zebras today and tarpans before their extinction, the horses of California were one of the most common prey items for many predators, due to their relative lack of defenses compared to other, more imposing herbivores. While the original American horses are now completely extinct, the genus Equus was unintentionally reintroduced by the Spanish in the 17th century, and persist to today. These animals are commonly known as Mustangs, and while they are indeed wild living, they are most commonly referred to as "feral" animals due to their domestic ancestry, arbitrary as this definition may be. </div>
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<span style="font-size: x-small;"><i>Smilodon and Columbian mammoths, by Mauricio Anton</i></span></div>
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The last aspect of prehistoric California that must be touched on is the predators. As with its herbivore guild, ancient California had an unusually high diversity of carnivores. There were several animals that have persisted to today, such as the Grey wolf, Coyote and Cougar. Even these however differed from the ones today, and were generally larger than their modern counterparts, as competition was greater and prey far more plentiful. Probably the most famous predator found in La Brea was the sabertooth Smilodon, specifically the species S. fatalis. A large and robust animal, it exceeded any extant big cats in size, and seems to have been by far one of the most abundant and successful predators. It was not however the largest, that title goes to the American lion. Far larger than extant African lions, it dwarfed even Smilodon, and would have been the unrivaled apex predator of its environment. Despite the huge size difference however, it was nevertheless the same species as those still found in the old world, Panthera leo. The difference in scale may have been a result of Bergman's Rule, which says that animals in colder regions typically have larger body size than equivalent species further south.<br />
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Another sabertooth inhabited California 11,000 years ago, namely the Scimitar cat of the genus Homotherium. Slightly smaller but more gracile than Smilodon, it seems to have been more of a pursuit predator, capable of hunting faster prey than its slower relatives. Given its smaller size and more diminutive nature however, it would probably have been a frequent victim of kill-stealing by other, more powerful predators. The last big cat that must be mentioned when discussing Pleistocene North America is Miracinonyx, commonly called the American cheetah. Despite its name, it was not in fact a true cheetah at all, nor even a particularly close relative, but instead a case of convergent evolution, where two lineages evolve down similar paths.<br />
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<span style="font-size: x-small;"><i>Miracinonyx hunting an extinct species of Pronghorn, also by Mauricio Anton</i></span></div>
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The ancient world revealed in the La Brea tar pits is gone now, but from a geological perspective only very recently. Every single species currently inhabiting the regions around the tar pits once shared their habitats with the now extinct giants, and some even show signs of having co-evolved with them. The pronghorn is by far the fastest animal in North America, far quicker than the speediest extant predator, the wolf. They are not however too fast to escape the extinct American cheetah. Perpetually running from the ghosts of vanished predators, these relics of ancient ecological interactions give us a glimpse at the past, in a way perhaps more real than any bones we could dig up. They show us that the past was indeed a real place, that these animals really were alive once, and that they played an important role in the ecosystems of their time. As a last note to end the story of the tar pits, around 10,000 years ago, bones of two new animals appear in the tar. Humans and domestic Dogs. Shortly after, the bones of Sabertooths, Ground sloths, Mastodons, and all of the other magnificent giants suddenly disappear. Climate change played no role here, the true perpetrator is obvious.</div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-76092678176568557472015-10-17T12:21:00.001-07:002015-11-09T01:03:50.717-08:00Big cats of Europe - past and presentBritish big cats, German big cats, Danish big cats, French big cats. Every European country seems to be reporting sightings of mysterious, large, often black cats nowadays. Of course, in the vast majority of cases, these are either hoaxes or misidentification, the fact that melanistic animals are most often reported, despite being far rarer than individuals of normal colouration, should itself be a clue to this reality. Whatever the case. some of these sightings have possibly been of real big cats. In central Europe for instance, lynx are fairly widespread, and to a person unfamiliar with the animal, could quite convincingly appear as a leopard or jaguar. These sightings are less tenable on the British isles, but even in Scotland wildcats are present, if barely, and hybrids between them and domestics are often significantly larger than your average housecat. Barring the occasional zoo or circus escapee however, the only true big cats to be encountered in present day Europe is the aforementioned lynx. But this was not always the case. Today I will be talking about the history of big cats in Europe since the last interglacial, their distribution, diversity, success, and eventual downfall by way of spears and bows.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyKW9H0_EDWidfBp4WEDyeMEY4FUGKQhV5h0eoPxLRSBmmPKWJlQxYsc8kx6yhN0MBPPqSCinOk-2gdH-2crEqguQ15Z5ejXYUMhnGLk5iRQ5_JccbxjFJ2hwN6wElaGwVc0RWUBZnvv1H/s1600/HanauLuchs3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="265" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgyKW9H0_EDWidfBp4WEDyeMEY4FUGKQhV5h0eoPxLRSBmmPKWJlQxYsc8kx6yhN0MBPPqSCinOk-2gdH-2crEqguQ15Z5ejXYUMhnGLk5iRQ5_JccbxjFJ2hwN6wElaGwVc0RWUBZnvv1H/s400/HanauLuchs3.jpg" width="400" /></a></div>
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<i><span style="font-size: x-small;">An Eurasian lynx, the only real big cat left in Europe</span></i><br />
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<span style="text-align: left;">Our story begins during the last interglacial, also known as the Eemian, 130,000 years ago. This period was something akin to Europe's garden of eden, a place unspoilt by modern man, where elephants and rhinos roamed alongside deer and elk. Romanticism aside, it was indeed a magnificent time, also for the big cats. During the Eemian, Europe was home to 4 different big cats, the leopard, the lynx, the lion, and the scimitar cat(Homotherium). Of these, the latter is now completely extinct, but the others persist in Africa and Asia. The Leopard was absent from the northernmost regions, but the other 3 were present all throughout Europe. When the ice age finally arrived, it did not have a large effect on the cats. The leopard was restricted to the southern refuges, Italy and Spain, like most of the other temperate species at the time, but remained fairly common. The lynx too was forced back, not directly because of climate, but rather due to their ecological niche. Lynx are forest animals, and do not do well on tundra. The lions and scimitar cats however remained in northern Europe, right up to the glaciers. There they shared their habitat with a variety of other large predators, including wolves, bears, hyenas, and dholes.</span></div>
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This was the case for the majority of the ice age, up until 50,000 years ago, when modern humans first arrived on the continent. Shortly after, the scimitar cats promptly disappeared throughout most of their range. Typically thought to have died out around 40,000 years ago, newer findings have shown that scimitar cats at least occasionally entered Europe as late as 28,000 years ago. Leopards were also hit hard, though their decline was slightly more prolonged, they had gone extinct throughout much of the continent by 10,000 BC, but persisted for significantly longer in the eastern and southernmost parts, although the eastern populations in particular may represent later immigrants instead of relics of the original European leopard population. </div>
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<span style="font-size: x-small;"><i>A painting of a leopard in the Chauvet cave, france</i></span></div>
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Thus we turn to the two most resilient big cats in Europe, the lynx and the lion. Of the lynx, their story is relatively uncomplicated, as they have persisted until the present. Shy forest animals, they had an inherent advantage towards surviving in a human dominated environment. The rest of this article will be focusing primarily on the lions, for it is their story that is truly fascinating. As stated above, lions have been present in Europe for as long as all of the continent's other fauna, but what makes them so interesting is how long their lasted. The European subspecies, P. l. spelaea, survived as late as 10,000 years ago, 4000 years after the end of the ice age. Adaptable and widely distributed animals, their ability to persist may have been down to raw strength and tenaciousness. But resilient as they were, 10,000 years ago lions do indeed seem to have vanished from Europe. Normally this would be the end of the story, just yet another species wiped out by humans, but in this case something unusual happened. Several thousand years after having seemingly died out, lions suddenly reappear in Europe. Remains from Hungary have been dated to around 7000 years a<span style="text-align: center;">go, and are some of the earliest of what I will refer to as the "late" European lions. After their reappearance, lions once again became fairly widely distributed, from southern Central Europe through the Balkans including all of Greece and possibly northern Italy. They did not manage to make it back into the northern parts of the continent however, for reasons we may never know.</span></div>
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<i><span style="font-size: x-small;">Cave paintings of P. l. spelaea, also from the Chauvet cave</span></i></div>
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For the next several thousand years, lions remain a constant part of the European bestiary, and would have been intimately familiar to the people who lived alongside them. Despite this however, we in the 21st century still do not know particularly much about them. The most pressing question concerning the "late" lions is whether they actually represented a late surviving population of P. l. spelaea, or belonged to another subspecies that immigrated independently. Currently the bulk of the evidence points towards the latter. To begin with, if these really were late surviving "cave lions", where did they come from? spelaea was not distributed very far outside of Europe, making it unlikely that some yet undiscovered refuge existed in Asia. On top of this, what limited range they did have outside of Europe was quite far north, in what is now western Russia, but the "late" lions clearly came from further south, probably the middle east, not some central Asian region. Yet another mark against the "spelaea hypothesis" is that ice age cave paintings exclusively portray maneless animals, while Greek art clearly shows animals with manes. Considering how many of these cave paintings we have, it is improbable that they were all meant to be females. </div>
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<span style="font-size: x-small;"><i>A sculpture of a lion from Greece, clearly showing a mane</i></span></div>
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In conclusion, I find it most probable that the "late" European lions were members of Asiatic lion subspecies, which was distributed into Turkey nearly until the 20th century. Turkey is also the place the "late" lions most likely came from, further supporting this idea. Whatever their origins, one thing we can state for certain regarding the "late" lions is that, at least for a time, they were quite successful. Exactly why they were capable of spreading into Europe at a time when hunting pressure was at an all time high is not known, but it may be that the lions from Turkey were especially well adapted to humans, as evidenced by the fact that they persisted there until just 100 years ago. But as can probably be deduced from their absence today, they did eventually go extinct in Europe. Again. Lions were still present in Greece during the 1st century BC, but were reported as rare, and had already died out everywhere else. The last ones probably died sometime shortly after the supposed birth of Christ. it should also be noted that the lions used in the Colosseum by the Romans were not in fact from Greece, but instead imported from Tunisia, and belonged to the now also extinct Barbary lion subspecies. </div>
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As far as we know, this was the end of big cats(other than lynx) in Europe, unless one counts the Caucasus, where small numbers of leopards persist even today. There is no evidence for any populations of other species after this point. And where does this leave us? Today big cats are in trouble world-wide, even in their African stronghold. Poaching is an increasingly prominent issue, and habitat loss is accelerating. While it would undeniably be difficult, and while many tribulations would lie ahead, perhaps it is time for Europe to re-embrace its lost heritage, if only to save them from extinction globally.</div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com3tag:blogger.com,1999:blog-7897751509059623525.post-15024944498811146642015-10-14T15:30:00.000-07:002015-11-09T00:58:44.196-08:00Frozen in time: The illusion of stable ecological communities and the geological perspectiveEvolution as a process is, at its most basic level, relatively easy to understand: Slow adaptation over many generations favoring forms more well suited to their environment. This is of course so overly simplified as to border on flat out inaccuracy, there are so many complicated processes at play in evolution that one could not possibly do them all justice in a brief summary. The point however stands that the general perception of what evolution broadly speaking is can be defined as an endless process of refinement. We tend to perceive the species that exist today as perfectly adapted to their environments, fully capable of persisting and surviving on their own. After all, if this was not the case, how could they even be here in the first place? This mindset is not necessarily wrong at face value, species must be competitive in order in order to persist. The issue here is the lack of perspective. Species and populations that may seem stable and self-sustaining in the short term may actually be in a state of chronic decline over a longer course of time. The lifespan of an individual person is so fleeting compared to the vastness of deep time, that perceiving such declines is essentially impossible without the benefit of hindsight.<br />
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When we look at a pristine forest, an un-managed oldgrowth, we see a vast and complex community of plants and animals, each fulfilling its own role in the ecosystem. Trees of varies species tower above us, often forming dense stands, seemingly impenetrable and ageless. Yet this is an illusion. Pollen cores and fossil evidence clearly shows that forests, and all other ecosystems for that matter, are in a state of constant flux, everchanging, but on a timescale too slow for us to perceive. The communities of trees that a person visiting a Himalayan forest today might see would be almost wholly different from that experienced by a person walking through the same area just a few thousand years prior. But this state of constant change is not just an endless reshuffling, many species once common are now gone, and many that we today would consider "staples" of the forests will no longer be here millennia in the future.<br />
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<i><span style="font-size: x-small;">A Himalayan forest, not as unchanging as it may seem</span></i></div>
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This is not just a matter of local diversity, entire species that are presently highly abundant may very well disappear entirely in the geological near future. Looking back into the fossil record, we see all sorts of examples of this. Temporarily, for but a few million years, a species appears, becomes ubiquitous and abundant, and then suddenly dies out. There was no great calamity, few or no other species were affected, yet one moment they were there, and a million years later they have gone, leaving no descendants. It must be said that we are still talking about what we would consider long spans of time, several million years, but when compared to the history of life on earth, or even the 66 million years since the non-avian dinosaurs died out, it is not very long at all. Allow me to give an example: <i>Barylambda</i>. Living from the Paleocene to Eocene, it was a member of the order pantodonta. Pantodonta itself was quite a successful group, lasting for almost 30 million years, but Barylambda was far more short lived. It first appeared during the late Paleocene of North America, and was gone by the end of the early Eocene, seemingly without descendants. Quite a large animal, around the size of a small cow, it would have been an important component of the ecosystems it inhabited, a keystone species. Yet it did not last, and like 99% of all other things that have ever lived, it died out. </div>
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The key here is not that it went extinct, that was of course inevitable. What is interesting is the seeming lack of a cause. A major climatic event, the Paleocene-Eocene Thermal Maximum, or PETM, was ongoing while Barylambda existed. During this period, the global average temperature was raised by several degrees, and the planet was upwards of 5 degrees warmer than it is today. This did not however have a large effect on the terrestrial ecosystems of the world, as there was no noticeable spike in extinctions at the time, and as such was probably not the cause of Barylambda's demise. It seems, quite simply, that it eventually grew increasingly less abundant, and was slowly replaced by other animals such as Coryphodon. The latter appeared simultaneously with Barylambda, and coexisted with it for millions of years, yet lasted longer, before itself suddenly vanishing. That Coryphodon or any animals like it should have been directly responsible for the disappearance of Barylambda is unlikely, so the only real option we are left with is that slow environmental changes caused a gradual population decrease, while not having the same effect on other animals, eventually culminating in its extinction. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKBw9cdVn1LDafmD-kgIn0MMCGsl3djf30leMN7CrsHkioZ3w2rMU_XNgMPBIiOGG-nDZaSLUB_nj6Tk0mpoCMxXvYekvt03zLuYS8S9oYfIB9Ro4dUUWGOdANI9DpjLM8jSarkI3sx5f5/s1600/Barylambda-faberi-738x591.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKBw9cdVn1LDafmD-kgIn0MMCGsl3djf30leMN7CrsHkioZ3w2rMU_XNgMPBIiOGG-nDZaSLUB_nj6Tk0mpoCMxXvYekvt03zLuYS8S9oYfIB9Ro4dUUWGOdANI9DpjLM8jSarkI3sx5f5/s400/Barylambda-faberi-738x591.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>A pair of Barylambda in a Paleogene forest, by Roman Uchytel</i></span></div>
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Looking at the more recent past, the Great American Biotic Interchange, or GABI, offered several prime examples of this. The GABI itself is an incredibly interesting and complicated subject that deserves an article all of its own, but for now I will give a brief description: The GABI was an event that took place 3 million years ago, when the isolated island continent of South America finally came into contact with North America, after the creation of the Isthmus of Panama. This land bridge allowed for animals from both continents to freely disperse both north and south, the so-called interchange. It was however a very one-sided event, as the North American faunas were by far the most successful. Many native South American animals were wiped out by the newly arrived competition, as the northern invaders spread throughout the continent, but far fewer succeeded in spreading north themselves. Only a few groups of South American animals ever managed to make it into NA, and of those that did, the vast majority died out shortly after. It is these that we will focus on. Remember that these are species which successfully not only compete and persist, but expand their ranges, who actively adapt and evolve, and had you seen only the first million years or so of the interchange, you would point to as clear winners. Yet once again, without any clear cause, they suddenly died out. </div>
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One particular example of this is Titanis, a large flightless bird of the group phorusrhacidae, better known as "terror birds". It was the only phorusrhacid to make it into North America, and it managed to spread as far as Florida. While it lived, it would certainly have been a fearsome animal, a large and lethal predator, capable of both efficiently hunting and competing with other predators. It disappeared a bit less than a million years after the interchange, long after its South American kin had already died out. Why it survived when its relatives did not is in and of itself a great question, but it also highlights a very important point. Just because an animal is adaptable, just because it is capable of expanding its range, competing, dominating, and evolving, does not mean that it is going to last. Of the other South American animals that spread north, three groups persist today, the armadillos, the opossums, and the porcupines. Today they are generally regarded as winners of the interchange, groups which managed to adapt and spread, but as Titanis has shown, this is no guarantee of persistence. It has still not been very long since the GABI, and it is fully possible that at least some of these South American colonists will eventually die out as did their kin. </div>
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<span style="font-size: x-small;"><i>Skeleton of T. walleri, mounted at the Florida Museum Of Natural History</i></span></div>
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The main take-home from all of this is that nature is not as static nor as stable as we tend to think. It is comforting to believe that while the economy of your country or the politics of your tribe may change, the trees will always remain stable, a constant, but it is simply not the case. So let us not take what we have today for granted, because whatever happens in the future, however our influence on this planet may turn out, this will not last, not forever, maybe not even for very long.</div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com1tag:blogger.com,1999:blog-7897751509059623525.post-92061364886241902282015-09-26T06:28:00.000-07:002015-11-09T00:59:14.022-08:00Relict lineages and late surviving speciesWe all know how the story of a species goes; At some point it evolves, arising from a previous ancestor. Maybe it thrives and spreads far and wide, or maybe it remains restricted to a small area, persisting in relatively low numbers. If it does gain a wide distribution, it will probably split into multiple subspecies, and eventually, some of these may themselves evolve into what we would term a new species. Eventually however, animals recognizable as members of the original species will go extinct, descendants or no descendants. They disappear from the world, their role in the ecosystem taken by other creatures, or perhaps left vacant if said niches no longer exist. Whatever the case, they are gone. But the borders between extinction and survival are not as solid as many people think. First off, we have the aforementioned situation in which a parent species gives rise to further descendants. If the wild Grey wolf went extinct, Canis lupus would still persist in the form of the Domestic dog and Dingo, and any descendants that they may have. In this way, species with descendants never really go "extinct" in the technical sense, their lineage is carried on, but the distinct morphology and ecology is still lost. Another form of not-quite extinction is called Functional Extinction, when individuals of a species are still present, but persist at so low numbers that they will never be able to recover, and are doomed to eventually die out. An example of this would be the Thylacine, which while officially extinct by 1933, probably continued to persist in low numbers until at least the 50s. Despite this, the species itself was probably functionally extinct as early as the beginning of the 1930s, and by the time the last captive individual, Benjamin, died, the species had already been doomed to extinction for a while.<br />
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The type of not-quite extinction I will be talking about today is the concept of relict lineages, groups which, while long past their glory days, still exist in the form of at least a single species. For me to consider a lineage "relict", it must be represented by only a few species, typically only one, and must be in constant but slow decline. Relict lineages can persist for a relatively long time after the rest of their relatives die out, and these few remaining species are termed "late survivors", but if they continue for too long, say more than 5 million years, they are clearly capable of adapting and diversifying, almost certainly possessing quite a large population, and thus not properly considered "relict". In this post, I will be going over some hypothetical late survivors, how and when they may have lived, and why we don't know about them.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFTLUd5x3O85AbI4-O_jhOBl0x3fuTZi58I9UzeGZbQugOEgM5164bheBUri_6cD-a99KMxgoE0KwrLuDoV1X0oPZeBpNsDkaGnin8KZWEGpjdlFhkGYFq8bjz9pcE8sbiLK6BSiP6h2gB/s1600/-Benjamin-.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="250" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjFTLUd5x3O85AbI4-O_jhOBl0x3fuTZi58I9UzeGZbQugOEgM5164bheBUri_6cD-a99KMxgoE0KwrLuDoV1X0oPZeBpNsDkaGnin8KZWEGpjdlFhkGYFq8bjz9pcE8sbiLK6BSiP6h2gB/s400/-Benjamin-.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>The Thylacine Benjamin, last known individual</i></span></div>
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Studying relict lineages in the modern world is very difficult, and this is down to two primary reasons. First off, it is almost impossible to detect if a lineage is in slow decline, as they will still appear relatively abundant in the present. Even late survivors are quite well adapted to the environments in which they live, after all, otherwise they would already be extinct. For this reason, studying relict lineages is essentially only possible with the benefit of hindsight, as slow declines are easy to detect on a geological timescale, though the late surviving species themselves, as we will get to, often are not. The second reason why studying them in the modern world is difficult is much more simple: We probably killed most of them. Relict lineages are per definition only barely scraping by, capable of persisting in their current environment, but only at low numbers, ill equipped for change. Because of this, humans are essentially the worst possible enemy for a late surviving species, almost perfectly adapted to extinguish them. It is quite probable that most "modern" relict lineages are now extinct, before we could get a chance to study them. </div>
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Thus, to properly study relict lineages, looking into the fossil record is the easiest way, right? Well yes, but only in the sense that it is pretty much the <b>only </b>way. Relict lineages are not well suited for preservation. They persist at low numbers, live in times when we would not except to look for them, and exist for a relatively short timescale geologically. All of these factors combined make it extremely unlikely that we would find the fossils of late surviving species, and indeed we very rarely do. Relict lineages are pretty much a statistical certainty, they must have existed. Considering the amount of extinction events in Earth's history, local and global, there must have been at least a few cases where a few members of a lineage managed to survive, but not properly diversify in the aftermath. Thus relict lineages and late survivors fall more into the camp of thought experiments, ideas that can be considered, but never truly verified. We can assert that they may have existed, but never confirm it. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmJBaJmGp7g0Ybe8YszJJ-Gn5d56uxClUJPnGeqGDtUaC5Ik2h7_U1Qm6uZxYNe9bCpjaDJYKbDXf7QLyS9n-DODdXDFCs7uVf5FaHPxzgsaYt2F9bM577KGgeasOpe52FdaPP6RKoKndk/s1600/enhanced-22895-1408612676-7.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgmJBaJmGp7g0Ybe8YszJJ-Gn5d56uxClUJPnGeqGDtUaC5Ik2h7_U1Qm6uZxYNe9bCpjaDJYKbDXf7QLyS9n-DODdXDFCs7uVf5FaHPxzgsaYt2F9bM577KGgeasOpe52FdaPP6RKoKndk/s400/enhanced-22895-1408612676-7.jpg" width="400" /></a></div>
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<span style="font-size: x-small;">The giant millipede Arthropleura. A rare case of a confirmed late survivor, as at least one species survived into the early Permian</span></div>
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As an example, I will focus much of the rest of this post on a particularly famous concept for a relict lineage, late surviving non-avian Dinosaurs. Now to be completely clear, I am not talking about the Mokele-mbembe, or any other alleged modern day animals. When I say late surviving non-avian dinosaur, I mean one that persisted into the Paleogene, anything further than that is highly improbable. I have already covered the Paleogene in a <a href="http://wheneuropewasanocean.blogspot.dk/2015/08/a-brief-guide-to-paleocene-faunas-of.html">previous post</a>, and I would advise you to read that one first to get some context. To briefly describe the environment of the early Paleocene however, it was a world mostly devoid of any large animals. Most animals even slightly specialized had died out, including the majority of pure herbivores and carnivores, leaving mostly small omnivores, and a fairly large amount of insectivores. The biggest creatures at the time were probably mammals about the size of a cat, but even these were rare. The planet was covered nearly from pole to pole in rainforest, and both the temperatures and sea-levels were much higher than today. The seas were populated almost exclusively by fish, with the exception of small Crocodiles and Champsosaurs which had survived the extinction. </div>
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Taking these factors into account, we can try and see what non-avian dinosaurs possessed these traits. First off, with small size, adaptability, and a non-specialized diet being the most important factors determining what survived the extinction, it is obvious why Birds were the only Dinosaurs to make it. They were pretty much the single lineage most perfectly prepared for the situation, if anything was going to survive, it was them. But if we hypothesize that at least a single other lineage survived, maybe only for a million years, what would it be? Well, of the late Cretaceous Dinosaurs, it must be said that aside from Birds, the other small Maniraptorans probably seem the most likely. A diminutive Troodontid or Dromaeosaurid would probably be the most likely options, perhaps slightly disappointing for anybody hoping for late surviving Sauropods. Already pretty much identical to Birds, the difference here between a small Troodontid and early Avian is tiny, and they would both have looked and acted almost exactly the same. But this fact may actually help make Troodontids and Dromaeosaurids slightly less likely, as birds may already have filled all of the niches they could have taken. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnHHArm_E_GS3Dr7eBZQTnnS1-LRJI1z-11eM4BKhpL8UDz_NwO8M9hpVUbiUuuJjdK-mjTvTmvZ0PVzyvnHeXY4ycuweB8kj4sX152ZPM9WrDqNsL4ut2ejzUsS96yiRH6zaRZ6IKIHU2/s1600/Jinfengopteryx_wiki.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="243" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnHHArm_E_GS3Dr7eBZQTnnS1-LRJI1z-11eM4BKhpL8UDz_NwO8M9hpVUbiUuuJjdK-mjTvTmvZ0PVzyvnHeXY4ycuweB8kj4sX152ZPM9WrDqNsL4ut2ejzUsS96yiRH6zaRZ6IKIHU2/s400/Jinfengopteryx_wiki.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>The tiny Troodontid Jinfengopteryx, by Matt Martinyiuk</i></span></div>
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So what group of small, non-specialized Dinosaurs not similar in ecology to birds existed? The obvious answer here seems to be small Ornithischians. While the larger Hadrosaurs and Ankylosaurs were far too large to have survived, small genera such as Leptoceratops potentially could have. Leptoceratops in particular may be unlikely, as the animal was still very big compared to any other animals known from the early Paleogene. A smaller relative would have been an ideal match however, and may have been one of the most likely candidates. Another possibility is a small species of Pachycephalosaurid or perhaps an undiscovered miniscule Hadrosauriform, we simply do not know. What we do know for certain however is that even if any non-avian dinosaurs did survive, they would not have persisted for very long. Being the blank slate that the early Paleogene was, any species of dinosaur that managed to gain a foothold would almost certainly have rapidly diversified, thus becoming a successful part of the time's fauna, and probably spawning a long line of descendants. If a small Ceratopsian had become established in the early Paleogene, it is quite plausible that Mammals would never have become as dominant as they are today.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiG2FNozZg_pDLm9QAgcHnvdN8GgXnPEar9eEY2sWX7c-2qMrXd78KUpuf4ADXfO_putwexjY6Vhe2YbniWNSPh9C7pQxblmI0KDQvzQW0Bh3yoMfu2veON-GZ7Y92YmD6XEPoSxvDLWBtV/s1600/unesco-and-gryph0_csotony.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="287" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiG2FNozZg_pDLm9QAgcHnvdN8GgXnPEar9eEY2sWX7c-2qMrXd78KUpuf4ADXfO_putwexjY6Vhe2YbniWNSPh9C7pQxblmI0KDQvzQW0Bh3yoMfu2veON-GZ7Y92YmD6XEPoSxvDLWBtV/s400/unesco-and-gryph0_csotony.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Unescoceratops and Gryphoceratops by Julius Cstotonyi</i></span></div>
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At the end of the day, we do not know if any non-avian dinosaurs survived the k-pg extinction, just as we cannot know whether any other hypothetical late survivors actually existed. What we can however be sure of is that animals like them have existed in the past, small groups of practically defunkt creatures, clinging onto existence for just a little while longer than their relatives. Whether they be late surviving non-avian dinosaurs, Cretaceous Dicynodonts, or early Jurassic Rausuchians, relict lineages have existed, and some may still exist today, without us even realizing it. There is often something odd about them, like a Roman in Renaissance France, they seem temporally displaced, out of time and space. </div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-76687264974723052822015-09-23T11:30:00.000-07:002015-11-09T01:00:03.931-08:00The early Holocene of Europe - from 11,000 to 6000 BPThe Quaternary extinction is a much talked about subject today, as it is both fascinating in the context of prehistory, and simultaneously important in modern conservation. Typically defined as the rapid decline in global biodiversity during the late Pleistocene up until present, it is sometimes referred to as the sixth mass extinction in earth's history, the previous one wiping out the non-avian dinosaurs 66 million years ago. Personally, I dislike the term Quaternary extinction. The event mostly occurred within the last 50,000 years, making the term "Quaternary" odd, since the Pliocene and majority of the Pleistocene was not involved. Some have also referred to it as the Pleistocene extinction, which is equally incorrect, as it has continued up until the present. I prefer the term "Anthropogenic extinction", and have used it previously, as I believe it is more apt. It ignores the timeframe in which it has occurred, instead describing the primary causal factor, humans.<br />
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While it is true that the most dramatic of the Anthropogenic extinctions occurred either during the late Pleistocene or around the industrial revolution, in this post I will be focusing on a very different, but in some ways even more significant period, the early Holocene. The early Holocene is special in that it represents a relatively brief span of time, approximately 5000 years, in which environmental conditions were similar to today, yet direct human influence on the landscape was not. Instead, the most major human influences during the early Holocene were the same as those during the Pleistocene - hunting. While many of the most important megafauna were already gone by the time the Holocene began, several were not, and for just a few thousand years, we got a glimpse of something similar to what the world may have looked like had humans not existed.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj838TY2t2IsxrI_OxA0R8rVSL_wP-nVYtfmlY50GZ2BndXDRYPZCIxwlmuIVc6JvokcHRi9Gd_yQp9JzpVTRR5weJ46oeuTfGnDQxWcomJQ-1qHiU7UWkBig-OQH2iCv1IYcjWcKEo00Wv/s1600/Ice_age_fauna_of_northern_Spain_-_Mauricio_Ant%25C3%25B3n+%25281%2529.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="193" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj838TY2t2IsxrI_OxA0R8rVSL_wP-nVYtfmlY50GZ2BndXDRYPZCIxwlmuIVc6JvokcHRi9Gd_yQp9JzpVTRR5weJ46oeuTfGnDQxWcomJQ-1qHiU7UWkBig-OQH2iCv1IYcjWcKEo00Wv/s400/Ice_age_fauna_of_northern_Spain_-_Mauricio_Ant%25C3%25B3n+%25281%2529.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Late Pleistocene Eurasia, by Mauricio Anton</i></span></div>
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The typical view of the faunal changes through the Holocene is as follows: In the beginning of the period, the climate was still quite cold, and open tundra-like conditions were dominant. During these times, Reindeer, Horses, and other such animals thrived. As time went on however, the temperatures increased, and the open landscapes soon became covered in forest. Over the course of the early Holocene, the forests grew increasingly denser and darker, thus causing the extinction of the species dependent on more open habitats. This is of course an extreme simplification, but roughly represents what has traditionally been said. After this, the story goes, the forests remained deep and dark for several thousand years, before finally being cut down by humans during the early Bronze age. In this version of history, the Aurochs and Wisents are also typically referred to as forest animals. As I am going to explain here, this view is false in several ways. The core problem with this model of the Holocene is that it simultaneously downplays the role of Megafauna in shaping their environments, while exaggerating the effects of the climate. I am not a scientist, much less a paleoecologist, but here is a more modern version of the early Holocene, based on what I have read from actual researchers:</div>
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In the earliest Holocene, over 11,000 years ago, northern Europe was indeed covered mostly in tundra. Willows and Dwarf birch were present, but did not form dense stands. At this point, the landmass known as <a href="https://en.wikipedia.org/wiki/Doggerland">Doggerland</a> still covered much of what is now the North Sea, but was already decreasing in size. Outer Silver Pit Lake, now a valley at the bottom of the sea, was, as the name suggests, a lake at this point, and the rivers Rhine and Thames were both connected in a now submerged delta that flowed into the atlantic, and would have formed enormous wetlands. Mammoths were still clinging onto existence in some regions, while Saiga antelopes and Musk oxen continued to prosper. This was rapidly changing however. As the climate warmed, and trees began forming open woodlands, humans became more abundant, greatly increasing hunting pressure. By the end of the first part of the Holocene, the Preboreal, 10,000 years ago, Scots pine forests were common across most of western Europe, and animals such as Elk, Bison and Aurochs had returned from their southern refugees. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5QZ3VhblcC2dJhqGMtHNUXAFi4wKDuYOf_eKx87c1k4ejxjCB_IG2FDe3pKtpgNK_efZSD_100jNMZSJbGUpY2C2Db-QQNwq3f25okmHkMmtFX2lDrtxjX8uNvyYYyp1yOE2nZFe-rxLc/s1600/1011818_tcm9-329782.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="225" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh5QZ3VhblcC2dJhqGMtHNUXAFi4wKDuYOf_eKx87c1k4ejxjCB_IG2FDe3pKtpgNK_efZSD_100jNMZSJbGUpY2C2Db-QQNwq3f25okmHkMmtFX2lDrtxjX8uNvyYYyp1yOE2nZFe-rxLc/s400/1011818_tcm9-329782.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Open Scots pine forests like this would have been common during the Preboreal</i></span></div>
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Following the Preboreal period came the Boreal. At this point the climate was almost as warm as today, and the signs of the previous glacial period were beginning to disappear. Over the course of a thousand years, Doggerland almost entirely disappeared, resulting in Britain being cut off from the rest of Europe. The only part of the once large landmass that remained was an island known as the Dogger bank, which lasted until around 8000 years ago. All of the fauna we know today arrived during this period, but many of the now extinct species began to decline. At the end of the ice age, the European horse, also known as the Tarpan, had replaced the Przewalski's horse, a steppe species, but now it too was in heavy decline in many parts of Europe. This has typically been assumed to have been due to natural causes, as, it was claimed, the warming climate allowed the forests to grow denser, crowding out species such as the Tarpan. As our understanding of megafauna and the effects they have on the landscapes they inhabit has improved, it has become increasingly clear that this view is not accurate. High populations of grazing megafauna were almost certainly capable of keeping forest growth at bay, resulting in the creation of savanna-like wood pastures instead of dense forest. Ecologist Frans Vera has long contested the traditional view of early Holocene Europe as a continent-spanning forest, claiming instead that it consisted mostly of wide open plains and the aforementioned wood pastures. Partly as an experiment to demonstrate his hypothesis, he helped create the Oostvaardersplassen in the Netherlands, where huge herds of thousands of Horses and deer, along with some couple hundred Cattle, have succeeded in creating the open landscape he predicted. </div>
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There is a big problem with Vera's hypothesis however; It relies on the assumption that such huge herds existed during the early Holocene. Hunting pressure 10,000 years ago was not much lower than it was 6000 years ago, and it seems unlikely that herds of thousands of horses existed, at least not for long. During the early Boreal, it is probable that very large herds of Tarpans and other grazing animals did exist in some places at least, but they were already greatly reduced due to human hunting, and seem to have quickly been wiped out. By the late Boreal period, most of the grazing species had probably been reduced to such an extent that they could no longer prevent forest growth. As a result, they entered a sort of positive feedback loop, as the more their populations shrank, the more open habitat became overgrown, and the more open habitat became overgrown, the more their populations shrank. By the end of the Boreal, the Tarpan was extinct in most of western Europe, though it persisted for far longer in the regions where dry climate prevented forest growth.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1gufaJ8MMyLbGfhQHQ47HGgAX5BWUIbsuU64v4Me_9sCEXRoeYqe4O6PSfOUSzwQJZ-92Lzc_8nWi7Mpdg25EqQ7DnFjf9OJcvPcCBpzF39MkEudOeT52oN5yK52sYFc0gcNAnWi2QdjL/s1600/oostvaardersplassen-konik-horses-running-hans-kampf-cropped.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="200" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh1gufaJ8MMyLbGfhQHQ47HGgAX5BWUIbsuU64v4Me_9sCEXRoeYqe4O6PSfOUSzwQJZ-92Lzc_8nWi7Mpdg25EqQ7DnFjf9OJcvPcCBpzF39MkEudOeT52oN5yK52sYFc0gcNAnWi2QdjL/s400/oostvaardersplassen-konik-horses-running-hans-kampf-cropped.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>A herd of wild horses, akin to those that inhabited the Boreal period</i></span></div>
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Thus we come to the Atlantic period, the last part of what I have termed the early Holocene. During the Atlantic period, temperatures were actually higher than they are today, and sea levels rose up to 3 meters, before falling again during the Subboreal. During the Atlantic, the extinction rate finally began to slow, as most of the vulnerable species had already either died out or been reduced to isolated refugees where they were relatively safe. The Wisent went extinct in much of western Europe, but aside from this, relatively little else disappeared. What was left had been heavily diminished however. A few species which previously inhabited open habitats, such as the Aurochs, had managed to adapt to living in forest clearings and marshes, though they were still in continual decline. At this point, the primeval woodlands typically associated with the early Holocene had developed, as in the absence of any meaningful grazing pressure, the trees grew tall and dense. As the great canopies shaded out the forest floor, biodiversity began to decrease significantly, and many species were restricted to the coasts and wetlands, where woods were still more open. </div>
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This was the landscape that would remain for over two millennia, until our ancestors finally began cutting down the woods to make way for primitive agriculture. The Atlantic was in many ways something of a gloomy and dour period, marked by declining wildlife and dark woods. It is interesting in that it serves as a particularly good example of the danger that undergrazing can pose. While overgrazing is a big issue in many parts of the world, Europe included, the Atlantic period shows what happens when you go to the opposite extreme. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2szH3fFDZBqk-O_FiB9yL9m1xH8hkr5f0XYe7lPorObJRUiNAS2J7Gcn22VftWZ5mM9PY-Kq3w9M8R7eFZZmEbdBV8CGBepRZ6lC0ghBMM8PTzqF8enEH7teTc66ME9kxyu_ui8k6nx0Y/s1600/Biogradska_suma.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="277" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi2szH3fFDZBqk-O_FiB9yL9m1xH8hkr5f0XYe7lPorObJRUiNAS2J7Gcn22VftWZ5mM9PY-Kq3w9M8R7eFZZmEbdBV8CGBepRZ6lC0ghBMM8PTzqF8enEH7teTc66ME9kxyu_ui8k6nx0Y/s400/Biogradska_suma.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>An old-growth forest similar to the ones that covered most of Europe during the Atlantic</i></span></div>
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In many ways, the early Holocene stands as something of a lost eden. While the last interglacial is certainly a better example of a pristine and healthy nature, the periods of the early Holocene have the distinction of feeling particularly close. One can still see the echos of this time, when we walk through the old-growths of Slovenia or Poland, or when we uncover the remains of long gone giants, preserved in bogs and marshes. In a way, it was a more innocent time, one in which our control over the planet was not yet quite as apparent. In today's gloomy and often stressful world, there is some relief to be found in imagining yourself walking through those long lost woods, ones that had never seen neither axes nor bulldozers. But at the end of the day, even during the early Holocene, the world was already heavily altered by our actions. Many species that would have been if not for us were gone, and we can be certain that the world would have been a very different place, even back then, had it not been for us. As alluring as the notion of a pristine wilderness just a few thousand years ago is, it was nothing of the sort, an illusion, hidden deep in the woods.</div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-72679630078106568592015-09-10T08:10:00.001-07:002015-11-09T01:01:38.570-08:00Alien species and the future ecology of AustraliaFirst off, the next post will be about prehistory, I promise, this is the last conservation related post for a while. With that said, buckle in, as this is going to be a long one.<br />
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Species disperse, this is an universally accepted part of ecology and evolution. Eventually animals will spread from one area to another, and if the conditions in this new habitat are different enough that they favor unique adaptations, evolution will occur, possibly resulting in the creation of a new subspecies. When animals naturally disperse, we tend not to have a problem with it, at least in most cases. Take for instance the Cattle egret. This small Heron has rapidly spread to colonize most of the world, while even just a century ago it was mostly restricted to Africa. This seems to have been completely by its own doing, and thus we have allowed it. Another example of this is the Turtle dove, which rapidly spread from western Asia to most of Europe within a few decades, though it is now declining again.<br />
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<span style="font-size: x-small;"><i>The Cattle egret, conqueror of the world</i></span></div>
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However, when a species does not disperse by itself, or rather, when it is spread via Humans, we have quite a different attitude. These species are labeled "aliens", in order to signify their non-native status. More often than not, the word "invasive" is tacked on. These so-called "invasive aliens" are a mainstay of environmental coverage. They are often referred to as one of, if not the single greatest issue in conservation, the cause of nearly all problems, from habitat destruction to extinction and the spread of disease. If you can think of it, it has been blamed on alien species. In several cases this is completely apt, as many of these introduced species are indeed a major threat to local fauna and flora. An example of this is the Cane toad, which, upon being introduced(deliberately) to Australia, proceeded to wreck havoc on local predators. Another example is the case of the Brown tree snake in Guam, which single handedly wiped out almost the entire Avian fauna of the island. But these are still only a couple species, out of the tens of thousands that have been transported around the world by humans.<br />
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The vast majority of these, over 90%, never manage to become established. Of the 10% that do, another 90% are completely reliant on human activity, only persisting due to a constant stream of escaped individuals bolstering the population. Only the remaining 10%, or rather, 1% of all introduced species, actually manage to become established and self sustaining in the wild. And yet even of this 1%, the vast majority are not a problem, often confined to single sites, and even when they do spread, most species have little to no negative effect on biodiversity. It really is only the 1% of the 1% that go on to become true horror stories, like the Cane toad. These should not be ignored, and we must remain vigilant whenever a new species is spotted, but to condemn all introduced species despite 99,9 percent having no negative effect is just not reasonable. Unfortunately, this is exactly what we are doing. Many conservation bodies simply <b>assume</b> that any introduced species must be harmful, and so almost every single website mentioning any, and I do mean any introduced species, from flowers to frogs to birds, will invariably say something along the lines of "it causes significant damage to local species, and must be exterminated". It does not matter that the vast majority of introduced species have never been studied, and that of those that have, most do not have a demonstrably negative effect.<br />
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<span style="font-size: x-small;"><i>The Little owl, introduced to the UK by Humans, yet beloved by many</i></span></div>
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And so we come to the subject of this post, Australia. Australia, being the world's only(populated) island continent, is undoubtedly also the one most affected by "invaders". Today, it is populated by an astonishing diversity of introduced species, from Rabbits to Camels. Many of these, like Cats and the aforementioned Cane toads are indeed a bad thing, but as I will argue here, many are not, and in any case, we are stuck with them, and will just have to get used to it. First some context to set the scene: </div>
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Australia was once populated by a menagerie of beasts unlike any other. Terrestrial crocodiles, marsupial lions, echidnas the size of boars, it was a land of monsters. Then Humans arrived, approximately 50,000 years ago, and all of the species listed above were wiped out, either at the end of a spear, or by the fire that we spread across the land. When the dust from this first colonization settled, almost all of the megafauna was gone, with only the Kangaroos, Emus, and Thylacines remaining as reminders of what once was. Fast forward to 4000 years ago, when another wave of colonists arrive. This time, they bring with them the ancestors of what we now call Dingos, and shortly after this, the Thylacine and Tasmanian devil both disappear from the mainland. This was the Australia that the first Europeans encountered, a continent devoid of almost any Megafauna, populated by only a single large terrestrial predator. It was the perfect habitat for new species to arrive in. When we look back at Earth's past, we see that generally, some of the greatest migrations and diversification occurs in the aftermath of a catastrophe. These devastating events wipe out many local species, allowing new arrivals to settle without competition. This is essentially what happened in Australia. Without its prior megafauna, the continent was open to invasion by new large animals, and invade they did. Today Australia is now populated by Camels, Water buffalo, Pigs, Goats, Horses, and Donkeys. Along with these large herbivores came small ones, such as Rabbits. The one thing that did not immediately arrive was the predators, as they were held at bay by the presence of the Dingo. However, a single species can only exert so much dominance over a fauna, and in the absence of the Devils that would have otherwise helped control smaller introduced predators, carnivores began to arrive. The biggest factor that allowed for the arrival of larger predators however was not the preexisting conditions of Australia. Europeans did not much like the Dingo you see, and it was accused of all manner of horrible things, from killing sheep to eating children. Thus, it was heavily persecuted, and effectively wiped out in many parts of the continent. With it gone, there was nothing left to prevent invading predators from become established, and so they did. </div>
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Foxes and Cats are the principle "invasive" predators that Europeans brought to Australia. They rapidly spread across the continent, eating their way through the local faunas, and have had a devastating effect on Australia's wildlife. Several species have gone extinct possibly solely due to them, and many others are endangered because of them. But. And there is a But. In the places where Dingos still persist in large numbers, Foxes and Cats are noticeably less successful. That is not to say that they are not present, they are, but their numbers are quelled by these apex predators. The result of this is that Dingos have a tremendously positive effect on local faunas, as they heavily control the populations of Foxes and Cats, while being predators of larger prey themselves. This larger prey incidentally includes other introduced species, such as Camels and Horses. And this is where we get to the crux of my point. Many, if not most of these introduced species are not completely incompatible with the local flora and fauna of Australia, as long as they are regulated by some other force, chiefly large predators such as the Dingos and Tasmanian devils. Foxes and Cats, while definitely major predators of small marsupials, <b>can</b> coexist with them, as long as Dingos and Tasmanian devils are present. This is very, very important, as this brings us to the other part of my point. We cannot rid Australia of these introduced animals. Foxes and Cats, along with Rabbits and Camels, are here to stay. Sure, we can manage their populations, with some species to a higher degree than others, but they will always endure, and eventually, once said management stops, their populations will bounce back. Attempting to control introduced species via fences or culling is not only unnecessary, it is also completely and utterly futile.</div>
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<span style="font-size: x-small;"><i>A Fox in Australia. They are here to stay</i></span></div>
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But I am not just here to talk about how introduced predators can coexist with native faunas. Even when they do coexist, they obviously still have a suppressing effect on said native animals, and we would all prefer if they were not here. No, what I also want to talk about is the introduced species that do not have a negative effect, and yes, they do exist, in fact, there are quite a lot of them. Remember the Camels, Water buffalo, Horses, and Donkeys I mentioned before? Well, this is the part where I anger almost everyone reading this by claiming that they are in fact a good thing. Yes, you read that correctly. You see, while these large herbivores are often accused of many devious deeds, from overgrazing to the destruction of habitats, this view is, simply put, wrong. More-so, it is based on a lack knowledge of the continent and its ecological history. Back before Humans arrived, when Australia was still pristine, the Megafauna played an enormous role in the continents landscape. They trampled vegetation, preventing the development of monocultures, knocked over trees, creating clearings and openings, and formed temporary wetlands and ponds where they sunk the ground with their footsteps. Most vitally however, they caused natural disturbance. Because of the constant damage they dealt to the local vegetation, the environment was ever changing, always adapting to new conditions. This created a mosaic of habitats, allowing for a far greater diversity of life. In fact, there is evidence that, upon their extinction, as they no longer grazed the continent's foliage, dead twigs and leaf litter built up on the forest floor, and it was <b>this </b>that caused Australia's climate to dry out, as these huge piles of leaves began burning, and wildfires raged across the continent, reducing much of the once verdant vegetation to the dry, fire-resistant scrubland we know today. In other words, the past extinction of Australia's megafauna was the reason why it turned from quite a lush and verdant continent to the dry and often inhospitable place it is today. Theoretically, the reintroduction of large grazers and browsers could reverse this process, as they might prevent the buildup of leaf litter, thus allowing it to turn green once again. </div>
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This, coupled with the proven benefits of natural disturbance, serves to provide a compelling argument for the reintroduction of large herbivores to Australia. The problem is, unlike in Europe and the Americas, all of the Australian megafauna is gone for good. There are no close relatives, no species filling the same ecological niches, who graze, browse, and create disturbance in the same way. There are no Indonesian Diprotodons that can simply be lifted over to Australia. Thus, a reintroduction in the typical sense is impossible, and any large herbivores introduced to the continent will be very different from its original inhabitants. And yet, a fauna persisting of some sort of megafauna, even if it is a different one, would still more closely resemble that of pristine Australia than the depauperate and empty one many view as ideal. While they would not provide the same kind of disturbance, introduced megafauna would still provide disturbance in some form. And they, the "invasive" Horses, Camels, and Water buffalo that now populate the continent, do provide disturbance, they do cause change and diversity in the environment, and they do, I will argue, increase biodiversity. This is a controversial view, which has never to my knowledge been tested, and as such I must admit to it being to a large extent speculation, but at the end of the day, there are two main things we do know: 1. Australia was originally populated by a megafauna, one which provided disturbance and alteration in the continent's ecosystems, thus increasing biodiversity, and 2. The newly introduced species, while very different in ecology than the extinct megafauna, do in fact provide disturbance and alteration in some form, even if it is not the same as that provided by the extinct megafauna. </div>
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<span style="font-size: x-small;"><i>A herd of Camels in Australia. Like it or not, this is their home now</i></span></div>
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In conclusion, Australia's situation with introduced species is very complicated, and there are no clear answers. Not enough research has been conducted to properly determine exactly what effects many of these species actually have on their environments, and much of what we say is based purely on assumptions. What we can say for certain though is that, however much we may like or dislike them, these so-called invaders are here to stay. We have no hopes of removing them, and in the long term, they will go on to form the ecosystems of the future. The best we really can do is make sure that the wonderful Marsupials and other unique animals do in fact have a place in these future ecosystems, so that their descendants may still pass on these ancient lineages a million years from now. </div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-33145605252236335022015-09-09T06:32:00.000-07:002015-11-09T01:05:37.274-08:00The world that we forgotHumans are an inherently short sighted species. We do not think too far into the future, and rarely gaze much further back than our youth. At most, the average person thinks a few decades forward, and a century back, anything beyond that is largely forgotten, or ignored. For conservationists protecting nature, this cone of vision is slightly less narrow, often looking an entire century forward, and sometimes upwards of 500 years back. This allows them to view the general trends these last few centuries have experienced. But it is still a narrow view, and still does not offer one crucial thing; Perspective. Most conservation efforts focus either on preserving areas as they are today, or turning them back at most a few hundred years. Often the time just before the industrial revolution is used as a target, an ideal. In this post I will discuss why to properly conserve nature, one must look much further back, and how this lack of perspective and vision is choking nature today.<br />
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<span style="font-size: x-small;"><i>The Cairngorms of eastern Scotland</i></span><br />
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<span style="text-align: left;">When most people think of British nature, they probably think of the highlands. Vast, beautiful, and devoid of people, they are an icon of conservation. They are also however almost completely devoid of any wildlife to be conserved, and in many places one can walk for hours, barely witnessing any animals, with the majority of the species one does see representing common taxa, also found in urban and rural regions. The reason for this is quite simple: Animals need shelter to survive, especially in areas exposed to harsh conditions, such as windswept mountains. But the British highlands are almost completely devoid of any form of shelter or cover, and thus, very little can live there. This is not the only reason for this scarcity, other factors include persecution by game keepers, use of pesticides in the lowlands, and the general tendency for uplands to house less wildlife than the more fertile lowlands. Of these factors however, only the former plays a major role, as pesticide use rarely affects many regions of the uplands, and many areas of the highlands are not below the natural treeline. The root issue is simply the lack of habitat.</span></div>
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How does this relate to this lack of perspective and vision that I mentioned in the first paragraph? Well, the Highlands did not always look as they do today. In the past, only a few thousand years ago, they were heavily vegetated. Some regions were cloaked in forest, others in shrub, and many areas consisted of savanna-like wood pastures. This diversity of habitats was matched by an astounding diversity of wildlife, not typically associated with northern Europe. Then came agriculture, and with it axes and fire. The trees were felled and the woods burned, so that cattle and other domestic animals could graze the areas. Soon, fire turned the verdant habitats into monocultures of heath and little else. Heather you see, is a pioneer species, adapted to flourish in the aftermath of wildfires, deposit its seeds, and then give way to other species through natural succession. When the next wildfire comes, these seeds germinate, and the cycle begins anew. But in the heavily grazed, heavily burned moors created by humans, this succession never came. Trees and bushes were prevented from regenerating by the intense grazing pressure, and the heath was perpetually renewed by periodic burning. Thus the forests and pastures gave way, and were replaced by vast tracts of heaths, almost entirely devoid of life. Fast forward 2000 years, and this landscape has changed little. What has changed however, is our perception of it. While the first people to begin this transformation were very much aware of what came before, two millennia later, all memories of the ancient woods were long gone, and heath was now perceived as normal, or rather, natural. </div>
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<span style="font-size: x-small;"><i>A highland moor, once a verdant woodland</i></span></div>
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This brings us to modern conservation. As with the habitats it seeks to protect, the movement remained fairly unchanged for over a century, continuing the same age old practices. More precisely, when the movement began, it sought to, as the name implies, conserve nature. But the nature that was present throughout much of the country at the dawn of the movement was the depauperate heathland, and thus, it was chosen as one of the primary goals for conservation. It was quickly realized that without constant maintenance, these open areas would rapidly turn to shrubbery, and soon forest. To prevent this, a strict burning and grazing regime was implemented, mimicking the slash and burn tactics practiced by farmers for the last 2000 years. In practice, the conservationists implemented agriculture to protect what they perceived as nature. This meant an overabundance of sheep, repeated burning, and removal of any trees attempting to colonize the protected areas. They locked in place the agricultural landscape, denying it any ability to change. To this day, these areas remain as they have been for hundreds of years, barren, empty, and devoid of life. All of this is the result of a complete lack of perspective, a lack of awareness of what came before. Even of those who did know of the old woodlands, few wanted to see them restored in the place of moors. </div>
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A few pinewood remnants have clung on til this day, and as is the perceived duty of conservationists, they have been maintained, unchanged. The problem is that these woods were never a healthy, nor stable ecosystem. Many of them emerged within a brief timeframe, when conflict forced the farmers and shepherds to retreat from the mountains, allowing forests to regrow. However, since the farmers returned, and deer stalking created a financial incentive to increase the population of said animal to unnaturally high numbers, natural succession has halted, and nearly all of the trees in these forests are approximately the same age, all centuries old, and all beginning to die. This has been going on for decades, with many woods present just 30 years ago now gone, yet in most places, little action was taken. A reluctance to embrace change, and insistence that the nature of the future should continue to resemble that of the recent past, has been the demise of these last forests. </div>
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<span style="font-size: x-small;"><i>Lone Scots pines, remnants of a now gone forest. Conifer plantation in background</i></span></div>
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This issue is not exclusive to British isles, though they are one of the best known examples. It is endemic to almost all areas in which we have become accustomed to impoverished conditions. The extinction of megafauna(large animals) across most of the world has made this a nearly global problem, as conservationists and people in general from most countries have forgotten the ecosystems of the past. One such case is Australia, which is also possibly one of the most insidious examples. Australia once had a megafauna, just like every other continent, but here it was in a league of its own. Isolated from the outside world, ancient Australia was the sandbox of evolution, where animals long extinct everywhere else coexisted with wholly novel lineages. Giant terrestrial crocodiles hunted marsupial rhinos, huge kangaroos stomped through the outback, and giant monitors, which I previously discussed <a href="http://wheneuropewasanocean.blogspot.dk/2015/08/lizard-kings-giant-monitors-of.html">here</a>, stalked the bush. Then came humans, and the same story as Britain unfolded, except whereas when people first arrived in Britain, the megafauna was already gone(exterminated when humans reached their Mediterranean refugees during the ice age), the first humans in Australia encountered a world of monsters. It did not take long for them to reduce it to nearly nothing, both through spears and fire. By the time Europeans first arrived, most of the large animals had been extinct for over 40,000 years, while some species, such as the Thylacine, had been gone from the mainland for over 4000. </div>
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Today, we have a tendency to view pre-European conditions as natural, with the native humans living in harmony with nature, only for this to be disrupted as soon as the Europeans first arrive. While it is certainly true that conditions have tended to worsen after European colonization, on most continents the most severe destruction occurred long before. In other words, the idea that native populations lived in harmony with nature could not be any further from the truth. Going back to Australia, as this is a continent colonized by Europeans quite recently, the benchmark for conservation has typically been right before their arrival. The most ambitious conservationists sometimes mentioned returning Tasmanian devils to the mainland, but not until recently has this idea gained any real traction, and aside from this, conservationists have mostly been solely focused on ridding the continent of all introduced species. By now, it is well known that ridding an island, much less an entire continent, of a well established species is almost impossible, while introducing new or extirpated species is much easier. In choosing to focus only on the eradication of all non-native(read, post-European) species, and in no way attempting to reintroduce extirpated species, they have essentially chosen to spend all of their money and energy on fighting an impossible war, rather than implement more radical ideas that may actually be feasible.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRD1cfsT3iwngj_M9WIM3QTx2q4ujkWfM99gyFDZV8qZNCCCeG5cgLHDEM3xy0NM5boeqcoQymBadH5bLQqf8xERd3owc-2JMNysT3GJ2lUYkOBSnNaItv3QC-t6-Bvnhey-GxzpXKZKw2/s1600/diprotodon.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhRD1cfsT3iwngj_M9WIM3QTx2q4ujkWfM99gyFDZV8qZNCCCeG5cgLHDEM3xy0NM5boeqcoQymBadH5bLQqf8xERd3owc-2JMNysT3GJ2lUYkOBSnNaItv3QC-t6-Bvnhey-GxzpXKZKw2/s320/diprotodon.jpg" width="320" /></a></div>
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<i style="font-size: small;">The extinct giant marsupial Diprotodon, by Peter Trusler</i></div>
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The phenomenon of people forgetting the past, of accepting current conditions as natural, is known as Shifting Baseline Syndrome. Essentially, it involves every successive generation viewing the state of nature during their youth as natural. As species decline, and nature becomes increasingly poor over the years, successive generations come to view each progressing stage of the decline as natural, until eventually a species dies out, and while the generation witnessing the extinction may lament it, those who grow up in its absence will not. Unfortunately, as I have described above, conservationists are not immune from Shifting Baseline Syndrome, far from it. This one phenomenon is in large part responsible for the decline and extinction of many species, as those who may otherwise have helped nature, actually become its enemies. At its core, SBS is a positive feedback loop, which is exceedingly hard to escape. Nature has been in a state of constant decline for so long now, that what many people and conservationists view as natural, and a goal to be striven towards, is in fact an unstable and thus unattainable state, which can never be achieved for the same reason why, if you are a person who has just jumped off a building and landed on the ground, it is quite possibly to return to the roof or stay on the ground, but you cannot move 20 meters back up into the air and then stay there. If you return to a state of freefall, said fall will resume as soon as you return there, and you will soon be back to where you started.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpVPw_eDRPJU7rIbpuGwigrSXwdp1GySfHQPE-8J9a3NiEncy_bUZflTSdKYhrComXQUpTjbMkNLeD1Wu_zs8mA0J5kaj5iWBsg6Ht4cq4LYajwnV9FffuskYbzTlyzT6jPsq2-K-r_gB8/s1600/hippopotamus_antiquus___european_hippopotamus_by_lynus_the_porcupine-d5mm387.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="218" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhpVPw_eDRPJU7rIbpuGwigrSXwdp1GySfHQPE-8J9a3NiEncy_bUZflTSdKYhrComXQUpTjbMkNLeD1Wu_zs8mA0J5kaj5iWBsg6Ht4cq4LYajwnV9FffuskYbzTlyzT6jPsq2-K-r_gB8/s400/hippopotamus_antiquus___european_hippopotamus_by_lynus_the_porcupine-d5mm387.png" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Hippopotamus once lived in Europe. Whether or not you want them back, the perception of them as non-native is a case of Shifting Baseline Syndrome</i></span></div>
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Nature in Britain(and most of the world) was already in decline 500 years ago, so returning the country to that period will simply save some time, merely postponing the issue. The only true way to save an ecosystem is to make it self sustaining, and to do that, one must first remember how a functional ecosystem even looks. This is why fields such as palaeoecology and paleontology are so vital for conservation, because they allow us to see how things were before. While we can never return to this past state, the Diprotodon is gone, as is the Mastodon, we can use these past ecosystems as examples, templates from which we can create new and healthy ones. To understand the present and the future, one must first understand the past, and for far too long, conservation has not done this. Luckily, times change, and progress is beginning to occur, but that is a topic for another post.</div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-4555185929438837422015-09-05T08:22:00.001-07:002015-11-09T01:02:09.495-08:00Dawn of Dragons: The life and ecology of early PterosaursPterosaurs are a very well known group, both fossil-wise and through popculture. While Pteranodon is by far the most well known, Pterosaurs are actually quite diversely represented in popculture, as genera such as Dimorphodon, Rhamphorhynchus, and Quetzalcoatlus are also quite common sights. During most of the Mesozoic, these flying beasts were the rulers of the skies, with global distributions and an incredible diversity of species. But we are not going to talk about the later members of the group today, at least not most of them. This post is about the earliest Pterosaurs, how they lived, and where they came from, for while the media and documentaries tend to focus on the most impressive beasts, the early members of this group were just as interesting in their own right, and offer us an unique look into the evolution of flight.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8uFBlAm7OIiyZYQXnk8t5gSyUv0rxwadB_Xkxmq5X-68OliVvRdSOjMybqYkMofXiIwM10RnDEmWNUKYzdqLrPG-WwRifqK7gUSFZ8fDDs-tZfyWAVKP3z4kcC_LHdOtSgj_Kr25aF5K8/s1600/tumblr_mq1itcuPnA1rbztl0o1_500.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh8uFBlAm7OIiyZYQXnk8t5gSyUv0rxwadB_Xkxmq5X-68OliVvRdSOjMybqYkMofXiIwM10RnDEmWNUKYzdqLrPG-WwRifqK7gUSFZ8fDDs-tZfyWAVKP3z4kcC_LHdOtSgj_Kr25aF5K8/s320/tumblr_mq1itcuPnA1rbztl0o1_500.png" width="236" /></a></div>
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<span style="font-size: x-small;"><i>Hypothetical proto-pterosaur, by Mark Witton</i></span><br />
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<span style="text-align: left;">The first and most obvious thing that needs to be discussed when talking about Pterosaur evolution is what exactly they are, or rather, where they belong in relation to other animal groups. When first discovered, nobody was really sure what to make of them, and thus they were often depicted as Mammal-like, similar in appearance to Bats. This was in part to explain how these clearly "warm-blooded" animals could have existed, as at the time it was still believed that all Reptiles were sluggish and incapable of fast and efficient movement. Since then, as we learned more about these animals, it became apparent that they were indeed "Reptilian", more closely related to Squamates and Crocodiles than Bats or any other mammals. This view has only been strengthened since then, and for the last several decades there has been complete consensus that they are indeed Diapsids. The question often raised is where in the Diapsid tree they belong. In the past they have been variously proposed to be descended from basal-Archosauriforms, Protorosaurs, or Ornithodirans. Today the latter view is the most commonly held, and they are now regarded as a sister-group to Dinosauria, making them stem-Birds. </span></div>
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It must also be mentioned that some, or rather, one person, has argued that Pterosaurs are not in fact Ornithodirans. Neither are they Archosaurs. In his opinion, Pterosaurs are a group of Lizards. In Squamata. This man's name is David Peters, and no qualified Pterosaur researchers agree with his views. He is not himself a Paleontologist, and as such has no expertise on the subject, yet has amassed an incredibly large web-presence via his two websites, ReptileEvolution and PterosaurHeresies. Neither of these sites are trustworthy, and should never be used as references for any extinct animals, Pterosaurs or not. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEvvJvOVJDGQN7D_1QExEHmequpfmmJsIhDQ6v_Y-DZlkl_x2k-jJqF-Vh-YuiGM7uZ30hw0q9Q9aFDxSEDb_zVSpylh46zbUmHgVk2Mn4N5ArmlX2dU1viFAjfnd9e4I3QMhMUN4WWBjj/s1600/Scleromochlus+detail+low+res+Witton.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="198" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiEvvJvOVJDGQN7D_1QExEHmequpfmmJsIhDQ6v_Y-DZlkl_x2k-jJqF-Vh-YuiGM7uZ30hw0q9Q9aFDxSEDb_zVSpylh46zbUmHgVk2Mn4N5ArmlX2dU1viFAjfnd9e4I3QMhMUN4WWBjj/s400/Scleromochlus+detail+low+res+Witton.png" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Scleromochlus, also by Mark Witton</i></span></div>
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The earliest distinctive Pterosaur ancestors split off from the Dinosaur lineage around 230 million years ago, in the late Triassic. At this point, the animals had not yet gained their distinctive morphology, and the earliest Pterosaurs would have heavily resembled their Dinosauromorph-kin. We do not know of any confirmed non-flighted early Pterosaurs, so instead we tend to look to the basal Ornithodirans, who undoubtedly resembled early Pterosaurs in anatomy and lifestyle. The first of these animals we will be talking about is Scleromochlus. An early member of Ornithodira from the Carnian era of the Triassic, Scleromochlus was a small and agile animal. Similar in anatomy to the lizards of Squamata, one of its most distinctive features was the incredibly long legs it possessed. Due to this, it would probably have been capable of jumping quite effectively, as depicted in the above image. How exactly it lived is uncertain, but it would probably have subsisted mostly on Insects and other small Arthropods living in the many deserts of the Triassic.</div>
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Another typical early Ornithodiran was Lagosuchus. While not a Pterosaur ancestor, instead being a basal Dinosauromorph, Lagosuchus was, like Scleromochlus, probably representative of the basic anatomy and bauplan of the earliest Pterosaurs. As with Scleromochlus, Lagosuchus possessed long hind limbs, allowing it to move bipedally. It, along with its relatives such as Marasuchus, would have been effective predators of small animals, possibly including early Mammals, which were just beginning to emerge during their time. From these various genera, spread across multiple Ornithodiran lineages, we can conclude that the earliest Pterosaurs were probably small, bipedal creatures, dwelling in the Triassic deserts and forests. They may have been common parts of their faunas, though the lack of fossils makes this uncertain, and they were certainly diminutive animals, only attaining larger ecological roles when they finally took flight.</div>
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<img border="0" height="259" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjUbAr6PJ7GJ1osEOXqfh6D0FA8nZFk3zIn3BI9S5FI_hF7qKpE_wCgu8ccu2Aiic_EJ3kV0kHPTnTW0lumWSVd7KD97HyZyCRbdXvEkdkv4kYu2CWJwvd80Lz78SNVIN5IHvXFLBLjjssz/s320/peteinosaurus_by_ntamura.jpg" width="320" /></div>
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<span style="font-size: x-small;"><i>Peteinosaurus, by Nobu Tamura</i></span></div>
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The first known Pterosaurs were already flighted, and lived during the late Triassic, indicating that the group probably first emerged during the later half of the mid Triassic. These animals included Preondactylus, a small and long-tailed creature that lived in Italy, 228 million years ago. It would have hunted aerial insects and other such creatures, and was probably a poor flier, as were most early Pterosaurs. It is quite possibly that, while capable of powered flight, these early members of their lineage in fact mainly used their wings for gliding or short flights, instead preferring to hunt terrestrially. Another early Pterosaur was Peteinosaurus, a relatively poorly known animal whose fossils consist of several juveniles, none of which have heads, and some of which may not even belong to Peteinosaurus. From what we can tell, it too was a long-tailed, small-bodied animal, much like Preondactylus. Another Italian Pterosaur was Eudimorphodon, which despite its name was not related to the Jurassic Pterosaur. This animal lived at the very end of the Triassic, a few million years before the T-J extinction event. Unlike many other Triassic Pterosaurs, Eudimorphodon was not in fact a basal member of the group, and had several more derived traits. Its dental structure is indicative of a Piscivorous diet, what that has since been verified by the discovery of fish in an individual's stomach. This is interesting, as there is little evidence of later Pterosaurs living off fish. The classic "skim-feeding" hypothesis, which posits that some Pterosaurs fished by swooping across the surface and scooping up fish, has become increasingly more unlikely the more we learn about Pterosaur anatomy, and as such, it may be that the Piscivorous Pterosaurs, Eudimorphodon included, hunted by swimming down and catching their prey in a more conventional manner. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvuMBr09I4HHV72WRmrOvFlu9g-KC8pdMe3Xm7RtUG_Dcpr0ruTuWa0hgwIndcbvVHoSu8I8BCbpSH5E1SHZXMjVYQqnRzDKWzYyehwYhJqBlpBhfrEouZDJPO_drOFKBU51UhSYqr9cg0/s1600/4618566556.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="227" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhvuMBr09I4HHV72WRmrOvFlu9g-KC8pdMe3Xm7RtUG_Dcpr0ruTuWa0hgwIndcbvVHoSu8I8BCbpSH5E1SHZXMjVYQqnRzDKWzYyehwYhJqBlpBhfrEouZDJPO_drOFKBU51UhSYqr9cg0/s400/4618566556.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Dimorphodon, once again by Mark Witton</i></span></div>
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We now come to the only "famous" Pterosaur I will be discussing today, Dimorphodon. A fairly small and oddly proportioned animal, Dimorphodon lived during the early Jurassic, around 190 million years ago. It is notable for being the oldest Pterosaur for which three dimensional remains have been preserved, though no complete fossils have ever been found. Despite this, an abundance of individuals have been known for over a century, giving us a complete view of the animal despite the fragmentary fossils. Dimorphodon may be a relative of earlier Pterosaurs such as the aforementioned Peteinosaurus, but given the shaky state of Pterosaur phylogeny, this is far from certain. By far the most obvious and peculiar thing about this animal is, as the picture above quite aptly demonstrates, the size of its skull. While not particularly impressive compared to later animals such as the Azhdarchids, it is still far larger than that of other early Pterosaurs, and represents the beginning of a trend that would eventually result in truly odd-proportioned beasts. The reason why Pterosaurs, Dimorphodon included, were capable of having such enormous heads is because of the hollow and airfilled nature of their bones, meaning that what may look particularly large and clumsy for a Mammal, is in fact relatively lightweight on a Pterosaur. Dimorphodon was a very strong-legged animal, with particularly beefy hind limbs. During the 80s and 90s, this fueled quite a lot of debate over whether it was in fact a bipedal Pterosaur, but this has since been proven to be unlikely, since many other features of its anatomy indicate it would be very poorly suited for such a method of locomotion.<br />
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More plausible is the idea that Dimorphodon was an adept hunter on the ground, capable of chasing downs its prey. This is backed up by the fact that the animal had proportionally quite small wings, which may have meant it was a so-called "reluctant flier", much like Grouse and Anseriforms today, which prefer to remain on the ground. In fact, research by some scientists has indicated that Dimorphodon may have been a very poor flier in general, possibly only using its wings to escape predators. If so, this would represent an interesting side branch of the Pterosaur tree, one in which an early member of the lineage actually partly returned to the ground, a clear example of how evolution is not in fact a linear process.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhr4xT6IqHZsED4eGunkCNuxmpDuPfLUD8Vb6JgsE36rrPkBETGAIL0qsmrQUJGuiGlhmWiTcLdqBwk4Ji5o-xGXagWE_5Cabjm-smf4_EAUqR7RI6j5x3sl6Hw_XZW262mrNueZF-SEcX4/s1600/1280px-Dorygn_DB.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="243" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhr4xT6IqHZsED4eGunkCNuxmpDuPfLUD8Vb6JgsE36rrPkBETGAIL0qsmrQUJGuiGlhmWiTcLdqBwk4Ji5o-xGXagWE_5Cabjm-smf4_EAUqR7RI6j5x3sl6Hw_XZW262mrNueZF-SEcX4/s320/1280px-Dorygn_DB.jpg" width="320" /></a></div>
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<span style="font-size: x-small;"><i>Dorygnathus with a hypothetical tail form.</i></span></div>
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The last two genera that I will be discussing here are Campylognathoides and Dorygnathus, both from the early Jurassic of Germany. Campylognathoides had a comparatively short snout, with large eye sockets placed low in the skull, which has lead some researchers to speculate that it may in fact have been Nocturnal. The postcranial of this animal is not very well known, and like with Dorygnathus, the tail is a complete enigma. If it was a nocturnal animal, this would have explained how it avoided competing with its similarly sized contemporaries, who would have otherwise hunted much of the same prey. It is the most basal known member of Novialoidae, a group that lasted all the way to the end of the Cretaceous. Dorygnathus was also a member of Novialoidae, more specifically, it is an early Rhamphorhynchine, and basal to the group. A fairly typical early Pterosaur, it would probably have hunted bugs and other small Arthropods, though it may, as was the case with Dimorphodon, have been a capable hunter on the ground. Interesting to note is that evidence of Pycnofibres is reported on a specimen of Dorygnathus, which is yet more confirmation that this form of integument was ancestral to the group. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCwBp4-70cDfildrD_bBNbqxHounEaU-1ZpMrbfSWT_-kGVFp9CO_FPPVmCvZ_ZhJRkSqLaePlcqA0xYh-vypfvjdYKRE5yVFPVopfe15YplTr0qqfi6shQ27fr11A7newwkS-gSwuy8Lr/s1600/preondactylus-pterosaur.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="309" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgCwBp4-70cDfildrD_bBNbqxHounEaU-1ZpMrbfSWT_-kGVFp9CO_FPPVmCvZ_ZhJRkSqLaePlcqA0xYh-vypfvjdYKRE5yVFPVopfe15YplTr0qqfi6shQ27fr11A7newwkS-gSwuy8Lr/s320/preondactylus-pterosaur.jpg" width="320" /></a></div>
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<span style="font-size: x-small;"><i>Preondactylus from AMNH</i></span></div>
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All in all, the early Pterosaurs were fascinating, if not particularly diverse animals. Unlike Bats, who suddenly appear in the fossil record during the Paleogene, Pterosaurs allow us to much more thoroughly track the evolution of flight, giving us an insight into how this group first emerged. For evolution by natural selection to take place, the adaptations gained must be advantageous, and it is evident in Pterosaurs that even during their earliest days, they were graceful and perfectly well adapted creatures, hallmarks of their habitats as definitive as birds are today. While it is easy to think of them as an ancient and archaic group, Pterosaurs emerged at the same time as the ancestors of birds, and the only real difference is that they have not had the misfortune of meeting us. Thus, while they may no longer be with us today, it is important to understand their evolutionary history, in order to fully comprehend what role these amazing creatures played back in those days long past.</div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-23855091735543574742015-08-31T06:44:00.000-07:002015-11-09T01:02:33.665-08:00Life and death in the Wessex FormationThe Wessex Formation is a geological formation dating back to the early Cretaceous, 130 million years ago. It is a part of the Wealden Group, which in turn is part of the Wealden Supergroup. This Supergroup also houses the Weald Clay Group and Hastings Beds Group, which, along with the Wessex Formation, were home to some of the first dinosaurs discovered, such as Baryonyx and Iguanodon. During the early Cretaceous, the Wessex Formation, and Wealden Supergroup in general, was part of a large island in the Tethys, where Britain now is. It had a dry, fairly arid climate, with distinct wet and dry seasons, and where temperature differences between summer and winter were stark. Much of the Wessex lowlands during this period would have been mostly treeless, covered in shrubs and other low-lying plants. The uplands and floodplains on the other hand would have been much more verdant, at least for some parts of the year, and plausibly housed a greater diversity of species. Due to these differences in habitats, animals would probably have migrated across the island depending on the seasons, spending the fairly cool and wet winters in the lowlands, and the warm and dry summers in the uplands. In this post I will be covering several of the major groups present in this formation, from the smallest Crocodyliforms to the largest Sauropods.<br />
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<span style="font-size: x-small;"><i>Polacanthus at a creek, by John Sibbick</i></span></div>
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Like most British Fossil sites, the remains discovered in the Wessex Formation are numerous, spanning multiple lineages, but generally poorly preserved and fragmentary. Because of this, we have an excellent overaching view of the faunal diversity of the Formation, but lack information pertaining to the individual species and genera. Among these is Polacanthus, an early Ankylosaur that lived from approximately 130 to 125 million years ago. Restorations of this animal are typically based on Gastonia or other early Ankylosaurs, as they were probably closely related. Estimates put Polacanthus at around 5 meters in length, which would have made it a rather small herbivore for the time, but its thick plated and spiked armour would probably have been deterrent enough for most predators. Where exactly Polacanthus fits in Ankylosaur phylogeny is not certain, but some researchers have placed it as a basal Nodosaurid. Another Ankylosaur that may have coexisted with Polacanthus is Hylaeosaurus, a similarly sized animal from the same region, though it may have been extinct by the time of the Wessex Formation. </div>
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Alongside Ankylosaurs, the largest Ornithischians in the formation would have been Iguanodonts, both of the genera Iguanodon and Mantellisaurus. These were both far larger than Polacanthus, with the biggest species of Iguanodon reaching upwards of 10 meters, possibly even 13. Iguanodonts were a group of basal Hadrosauroids, more primitive than the true Hadrosaurs of the late Cretaceous. Probably the most abundant medium to large sized herbivores in their habitat, the smaller species and juveniles would have been one of the main prey items for the predators of the time, though the largest adults would have been virtually immune to predation. A well noted feature of the Iguanodonts is their peculiar thumb spike, which was probably used for intra-specific combat more so than self defense, as was previously thought. Famously originally misinterpreted as a nose horn, this was later corrected when more complete remains of Iguanodon were discovered. </div>
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<span style="font-size: x-small;"><i>A large herd of Iguanodon moving along the coast, from Walking With Dinosaurs</i></span></div>
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Five Sauropods are named from the Wessex Formation, but none are well known. Large animals generally do not fossilize well, and in the already poor conditions of the English fossil beds, Sauropods are typically only known from few and fragmentary remains, as is the case here. Three of the Wessex Sauropods, Eucamerotus, Luticosaurus, and Ornithopsis are classified as Titanosaurs, while of the other two, one is considered a Turiasaur, and the other not assigned to any specific group. The more well known species Pelorosaurus is known from the slightly earlier Hastings Beds, but some of the remains in the Wessex Formation may actually belong to this genus. The Wessex Sauropods were probably quite large, with the biggest possibly reaching 20 meters in length, as more complete fossils from earlier genera such as Cetiosaurus, a Jurassic animal, show that despite being an insular fauna, island dwarfism does not seem to have had a large affect on British dinosaurs, as while the species here are typically smaller, they are still often large in their own right. This is probably because Britain was part of one of the largest islands in the European archipelago, a so-called subcontinent. </div>
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<span style="font-size: x-small;"><i>Pelorosaurus, by Nobu Tamura</i></span></div>
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Of the Wessex Formation's non-Dinosaurian fauna several species of Pterosaurs are known, among these the large Ornithocheirus. While some species of this genus had wingspans of up to 5 meters, the remains known from Britain indicate a smaller animal, only reaching around 2.5 meters from wing tip to wing tip. While Ornithocheirus, like many Pterosaur genera, was previously speculated to be a piscivorous species, later research on Pterosaurs in general has made this unlikely. More plausibly, it would have hunted small terrestrial animals such as Mammals and lizards, though it would probably also have been an opportunistic scavenger. Another Pterosaur found in the Wessex Formation was Istiodactylus, a relatively large species, which with a wingspan of up to 4 meters may have been the biggest Pterosaur in its habitat, barring any yet undiscovered species. Sometimes called "Duck-billed" due to the shape of their jaws, though these were filled with small sharp teeth, adapted for slicing through flesh. </div>
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Another common non-Dinosaurian part of the Wessex fauna was the Goniopholidids, Primitive and superficially Crocodile-like Neosuchians that died out at the end of the Mesozoic. They ranged from the diminutive Vectisuchus, which was only 1.2 meters long, to the large Anteophthalmosuchus, which could grow to up to 3.5 meters long. These would have filled essentially the same niches as modern Crocodiles do, hunting small Dinosaurs such as Hypsilophodon. One interesting thing to note however is that due to the extreme aridity of early Cretaceous Britain, many of the island's wetlands would almost entirely dry out during the summer. Due to this it is plausible that many of the larger Crurotarsans would have had to essentially hibernate through this period, subsisting on very low amounts of food for months at a time, while the smaller species would probably be capable of surviving in the muddy riverbeds and dried up lakes during these periods.</div>
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<span style="font-size: x-small;"><i>Ornithocheirus, by Julius Csotonyi</i></span></div>
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The last large part of the Wessex Formation's fauna that I have yet to talk about is the Theropods. While some of the larger Goniopholidids may have been keystone predators of smaller species, the Theropods were the undisputed top predators of their environment. Several famous Theropods are known from the Wessex Formation, including the Spinosaurid Baryonyx, a gracile and piscivorous animal that was nevertheless the largest predator in its habitat. Another significant animal from the area was Eotyrannus, a genus with a particularly convoluted history of classification. Originally thought to be a basal Tyrannosauroid, hence its name, it was later reclassified as a Megaraptorid. However, since Megaraptors have now also been reclassified as a group of derived Tyrannosauroids, this means that Eotyrannus is technically <i>still </i>a Tyrannosaur, albeit not a basal one. Eotyrannus itself was a fairly small animal, at only 4 meters in length, and would most likely have hunted small Mammals and dinosaurs. By far the largest predator(aside from Baryonyx) in the Wessex Formation would have been Neovenator, a genus of large Allosauroids. These impressive animals could reach almost 8 meters in length, and as such would have been more or less undisputed. Interesting to note is that some cladograms actually find it to be close to the Megaraptorans. However, the aforementioned and more recent findings placing the Megaraptorans within Tyrannosauroidae make this unlikely.<br />
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The Wessex Formation was also home to several small and diminutive Theropods, but most of these are still very poorly understood, and cannot be confidently confirmed to belong to any group. An exception to this is Aristosuchus, which despite its name is actually a Compsognathid, along with Calasmosaurus, another Compsognathid, which is estimated to possibly have reached upwards of 5 meters, making it one of the largest members of its group. The other, more poorly known small Theropods include Yaverlandia, originally identified as an Ornithischian but now known to be some form of Maniraptoran, Ornithodesmus, a small Dromaeosaurid, originally thought to be a Pterosaur, and Thecocoelurus, which may in fact be one of the earliest Ornithomimosaurs.<br />
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<span style="font-size: x-small;"><i>Eotyrannus hunting Hypsilophodons, by Luis V. Rey</i></span></div>
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The Wessex Formation is fascinating for the same reason that so many other British fossil beds are, namely the incredible diversity in species preserved there. Groups of many lineages, some newly emerged, others near the end of their existence, all seem to be present in these faunas. While this could perhaps be argued to be a result of the insular nature of the British faunas, it seems more likely that these Formations are merely more complete than most others, and that in reality, this diversity was present across most of the world during much of the Mesozoic. In this regard, the British faunas, the Wessex Formation included, give us a particularly clear view of just how lively and biodiverse Mesozoic ecosystems would have been, allowing us to more easily reconstruct the sort of interactions that would surely have taken place all those millions of years ago. </div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-23435396034905775592015-08-30T05:11:00.000-07:002015-11-09T01:03:10.466-08:00A brief guide to the Paleocene faunas of Europe66 million years ago, the world was dominated by dinosaurs. Great herds of Hadrosaurs and Ceratopsians migrated across the continents, stalked by hosts of Tyrannosaurs, Dromeosaurs, and in some places Abelisaurs. Then one fateful day, the Chicxulub asteroid smashed into Earth, and in an instant, the age of Dinosaurs was over. When the dust settled, all Dinosaurian lineages except the Avians were extinct, and along with them were the Pterosaurs, Plesiosaurs, Mosasaurs, and a large chunk of pretty much everything else. This event, the K-PG extinction, marked the end of the Cretaceous, and the beginning of the first period in the Cenozoic. The large animals were gone, and the planet was essentially empty. This was the setting of the Paleocene, an odd and depauperate world, in many ways owing more to the Cretaceous than the periods that would follow.<br />
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<span style="font-size: x-small;"><i>The Chicxulub asteroid impact, marking the end of the Cretaceous</i></span><br />
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<span style="text-align: left;">To understand understand the Paleocene world, one must first understand the concept of a </span><b style="text-align: left;">recovery fauna</b><span style="text-align: left;">. A recovery fauna is an assemblage of species that arises following a catastrophe of some sort. Local recovery faunas could include assemblages of pioneer species following a volcanic eruption, which form low-diversity ecosystems in the devastated areas. The Paleocene was a global case, in which every fauna on the planet was a recovery fauna. Nowhere was spared from the asteroid, and thus, during the Paleocene, the world would have appeared as an oddly empty place. The Mammal groups we know today had not yet evolved, so there were no Rodents, Carnivorans, Perissodactyls, or any other such animals, with the possible exception of Primates, which may have been present since the latest Cretaceous. Instead, the Paleocene was populated with leftover genera from the Cretaceous, making it seem more like a depleted extension of that period, rather than the first part of the age of mammals. Indeed, had one looked only at this period, one could be forgiven for getting the opposite idea, as giant flightless birds and other reptiles would have been by far the largest animals in these faunas, filling both the roles of large herbivores and apex predators. </span></div>
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<span style="font-size: x-small;"><i>Paleocene Europe would have been covered in dense rainforest, similar to this</i></span></div>
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The Mammalian faunas of the early Paleocene would have been almost identical to those of the late Cretaceous, but with far fewer species. Particularly hard hit were the marsupials, who in Europe were reduced from 9 to 1 genus. Placentals would have been common in this time, mostly consisting of small insectivores, primitive proto-Ungulates, and Primates or Primate-like animals. Another successful group was the Multituberculates, who, while now extinct, are in fact the group of Mammals that have existed the longest, spanning from the late Jurassic to the Oligocene, and thriving in Paleocene Europe. The Multituberculates did not belong to the same group as the Placentals and Marsupials, called the Therians, but instead seem to have been somewhere closer to the Monotremes, a group that today includes species such as the Platypus. The early Paleocene members of this group were superficially similar to rodents, but soon radiated into a variety of other forms, such as the North American Ptilodonts, which almost resembled squirrels. In Europe, a similar genus called Hainina would have filled roughly the same niche. </div>
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<span style="font-size: x-small;"><i>A Leptictid leaping into the air, from Walking With Beasts</i></span></div>
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Alongside the Multituberculates, Placentals were the other of the two most successful Mammal lineages in the early Paleocene of Europe. Already at the beginning of the period, Europe was home to a diverse assortment of Placentals, including the Pantolestids, an archaic group of semiaquatic piscivores. With powerful formlimbs and strong tails adapted for hunting in the water, they were a common group during this timeframe. Another successful group was the Leptictids, who had their origins in the Cretaceous, but survived the extinction and went on to become very abundant during the Paleocene. Small insectivores of the forest floor, the Leptictids' most unique trait was their bipedal gait, providing them with a method of locomotion similar to that of a Kangaroo. Probably the largest of the Paleocene Mammals were the primitive Ungulates of the time. Survivors of the K-PG extinction, these so-called "condylarths" were more basal than both the Artiodactyls and Perissodactyls, and possessed traits from both of them. As a testament to how odd some of the Paleocene fauna truly was, some Ungulates such as the Mesonychids were probably predators, though given their phylogeny, they were most likely actually omnivorous. </div>
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During the later parts of the Paleocene, several species entered the continent from North America, despite interspersal still being fairly limited at the time. Among these were the true Ptilodonts Liotomus and Neoplagiaulax, which joined the already present species Hainina. Condylarths continued to diversify, becoming some of the most common Mammals in Europe at the time. Primitive members of the group like the Arctocyonid Prolatidens, which were already present in the earlier parts of the period, diversified into a variety of forms, such as Landenodon, Mentoclaenodon, and Arctocyon. The latter in particular was an impressive animal, growing to be as large as a small bear. While an intimidating and powerful beast, Arctocyon was probably primarily herbivorous, only occasionally ingesting meat. </div>
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<span style="font-size: x-small;"><i>The Condylarth Arctocyon, from Wikipedia</i></span></div>
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While Mammals have been the focus of this post, this is a slight injustice, as they were not in fact the most common animals in the Paleocene of Europe. Reptiles of many lineages were far more numerous, and some even reached very large sizes. Amongst these were the Dyrosaurids, a group of archaic crocodiles which had survived from the Cretaceous, and were the largest marine predators in the Paleocene seas. On land, terrestrial crocodiles such as the Notosuchians were commonplace, arguably also leftovers from the Cretaceous. The most well known of the non-Mammalian inhabitants of Paleocene Europe however were the giant terrestrial birds, mostly belonging to the Gastornithidae, a group of large flightless Anseriformes. Chief among these was the bird Gastornis, While previously thought to have been a carnivore, Gastornis is now known to have had a primarily herbivorous diet, making it the largest herbivore in its habitat, probably only competing with other giant birds and the largest of Condylarths. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhFmODeuuN3thJs7Ytnp9oW_lLulw32fKa-M0vy8T-TZWr6g1a7rAzRKv2Hdrq3AC71bn8dQKe68_tABM6swFszfgORosVxceNhgnSMw0JJ8fNLjIE3TJhDJ8h099IQllGNT4YxN1hyK3qM/s1600/Gastornis.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhFmODeuuN3thJs7Ytnp9oW_lLulw32fKa-M0vy8T-TZWr6g1a7rAzRKv2Hdrq3AC71bn8dQKe68_tABM6swFszfgORosVxceNhgnSMw0JJ8fNLjIE3TJhDJ8h099IQllGNT4YxN1hyK3qM/s320/Gastornis.jpg" width="300" /></a></div>
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<span style="font-size: x-small;"><i>Gastornis and chicks by Charles R. Knight</i></span></div>
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Long as this post has been, I have still only covered a tiny fraction of the Paleocene fauna of Europe. While relatively empty compared to later periods, the ecosystems of the Cenozoic's first period were still rich and bustling in life, and describing them in their entirety in one post is neigh impossible. As there is so much more to learn about this fascinating lost world than I could ever hope to cover here, I will recommend a fantastic book on the subject: Mammoths, Sabertooths, and Hominids; 65 million years of Mammalian evolution in Europe, by Jordi Agusti and Mauricio Anton. You can get it on Amazon <a href="http://www.amazon.com/Mammoths-Sabertooths-Hominids-Mammalian-Evolution/dp/0231116411">here</a></div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com2tag:blogger.com,1999:blog-7897751509059623525.post-18488752932392487802015-08-29T02:39:00.001-07:002015-11-09T01:03:40.117-08:00Lizard Kings: The giant Monitors of prehistoric AustralasiaToday, the Komodo dragon is quite a well known animal. As the largest lizard in the world, it carries a prestigious title, and it is indeed an impressive creature. The Komodo dragon is however only one part of a greater puzzle, that being the giant Monitor lizards that once dominated much of Australasia. Not much is known of these enigmatic animals, but the bits and pieces we do have seem to reveal what was previously a widespread and successful group, now mostly extinct.<br />
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The most famous of the giant Monitors is obviously Megalania, a huge lizard that inhabited southern Australia up until the arrival of humans, when it was wiped out in the Anthropogenic-extinction. Known only from fairly incomplete remains, despite being a very recent animal, Megalania has been the subject of much debate, chiefly over its size. Original estimates from when it was first discovered placed it at 7 meters in length, what that would have made it a truly enormous animal, but in 2002, Zoologist Stephen Wroe found it to be a great deal smaller, at only 4.5 meters in length. This was again changed in 2009, when Wroe himself along with other researchers upsized it to 5.5 meters. In truth, we have no idea how large Megalania really was, since we do not know of its proportions. Ralph Molnar said in 2004 that if it's proportions were like those of a Komodo dragon, it would have been 7 meters long, while if they were similar to a Lace monitor, it would be upwards of 8.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq77jbiTzkTcC4I2eoyL665wbFOTgXG-ssv3Q3uRLJF4m5M543DXDTamDzSTPhRGPUMOH8LSrSGH7o19qkd1EetwT5ff8xA5N65BbYAF3nuR607sTFxXtc9rQ9bx1Xj2vhIhUyIempRfPy/s1600/89bf494941731a8a34f58bbdadf4efa7-d8qvivh.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="170" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhq77jbiTzkTcC4I2eoyL665wbFOTgXG-ssv3Q3uRLJF4m5M543DXDTamDzSTPhRGPUMOH8LSrSGH7o19qkd1EetwT5ff8xA5N65BbYAF3nuR607sTFxXtc9rQ9bx1Xj2vhIhUyIempRfPy/s400/89bf494941731a8a34f58bbdadf4efa7-d8qvivh.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Varanus priscus, by Vlad Konstantinov</i></span><br />
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Another important thing to note about Megalania is that while it was certainly in a league of its own, far greater in size than any other known lizard, it still appears to have been a member of the genus Varanus, with its scientific name being Varanus priscus. This is a testament to the astounding diversity within Varanus, a genus which includes both the Komodo dragon and the Dampier Peninsula monitor. Because of this great diversity, it is also difficult to place V. priscus in the family tree, as while it looks superficially similar to the Komodo dragon, it may not have been particularly closely related to it at all. The fact that the Varanus keeps producing giants, many of which seem to have evolved independently of each other, means that there are probably many other species out there, waiting to be uncovered. Megalania was distributed across southern Australia, and the Komodo dragon once across the entirety of Flores, but the other islands in the archipelago most likely also hosted giant monitors at some point, even if we have not yet discovered them. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8sJ2YNVxsv2E-mCHw3KNLy4rfQrb5uV1MUy0vtvRvcrxMgMRGx4yzQv3Ne6EyyF_i0-rujK1YO-dXADYTkxWq33E3Kx9uxKUTxLUCNQKpdunXh3ZSDBQzrK-YhqEF8nN4UUmMqCgNxmm7/s1600/komodo-dragon.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="258" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi8sJ2YNVxsv2E-mCHw3KNLy4rfQrb5uV1MUy0vtvRvcrxMgMRGx4yzQv3Ne6EyyF_i0-rujK1YO-dXADYTkxWq33E3Kx9uxKUTxLUCNQKpdunXh3ZSDBQzrK-YhqEF8nN4UUmMqCgNxmm7/s400/komodo-dragon.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>A Komodo dragon, the largest extant lizard</i></span></div>
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A particularly interesting point about the Komodo dragon is that while it is often portrayed as a case of island gigantism, an animal which evolved large size due to insular conditions and a lack of competition, the opposite may in fact have been true. Fossil evidence shows that the ancestors of the Komodo dragon actually evolved on mainland Australia, only recently spreading to Indonesia. While the Australian dragons are extinct, the great size difference between mainland giants such as Megalania and the Komodo dragon show that it may in fact have been an island <i><b>dwarf</b></i>. </div>
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While Varanus seems to have a propensity for spawning giant lineages, the question still remains as to how they lived, and what role they played in the ecosystems they inhabited. Obviously we can still study the Komodo dragon, but it is an insular species, and lives in an ecosystem mostly devoid of other species. It was not always like this however. 13,000 years ago, Flores was a very different place from today, populated by dwarf mastodons, tiny humans, giant storks, and many other odd island endemics. In this ecosystem, it seems that the Komodo dragon may have been the apex predator. Today the only remaining dragons are from small islands such as Komodo, and are probably smaller than the inland dragons, but we can assume that their sizes were fairly similar, give or take a few meters. In this environment, Komodo dragons may actually have preyed on the dwarf mastodons and tiny humans, </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuyQ1Qgrgf_2N1ITRYP9wzr2hF-FGpzNz8r0G2uY_biw44aC1jKe0JX6TpMMbbA2QKxFggVMNGkY1NjE2Q7n2fVE3_rM28MDZMMYV2GYJvwe5KUt9F-7COe6VNwMlm7DkbNhRW49MePomZ/s1600/trusler-megalania-990x631.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="253" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiuyQ1Qgrgf_2N1ITRYP9wzr2hF-FGpzNz8r0G2uY_biw44aC1jKe0JX6TpMMbbA2QKxFggVMNGkY1NjE2Q7n2fVE3_rM28MDZMMYV2GYJvwe5KUt9F-7COe6VNwMlm7DkbNhRW49MePomZ/s400/trusler-megalania-990x631.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Megalania chasing a prehistoric Emu</i></span></div>
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While the Komodo dragons were sole rulers of their island kingdoms, mainland Australia was filled with predators of all shapes and sizes, some of which were larger than even Megalania. Thylacoleo, the marsupial lion, was, as the name suggests, a lion sized beast, and would have been one of the top predators at the time. Likewise, members of the now extinct Thylacine lineage would also have been abundant in prehistoric Australia, with some species significantly larger than the so-called "Tasmanian tiger" that was hunted to extinction in the early 20th century. But the true apex predators of Pleistocene Australia were not Mammals, but instead huge terrestrial crocodiles of the Mekosuchid lineage. While a predominantly small group for most of their history, they began rapidly increasing in size during the Pleistocene, eventually producing the genus Quinkana, which at 6 meters in length was possibly the largest fully terrestrial predator on the planet. Though possibly not as long as Megalania, this species would have been far heavier and more powerful, possibly even capable of chasing the giant Monitor away from its kills. While not the apex predator, Megalania would probably still have been one of the largest carnivores in its environment, dwarfing any of its contemporary Mammal predators. </div>
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But like all the other great Australian beasts, Megalania is now extinct, and has been so for 40,000 years. There has long been debate as to whether Megalania was driven to extinction by humans, or died out shortly before their arrival, but after a new study has firmly demonstrated that the early Aboriginals did coexist with them, it now seems likely that their demise was indeed at our hands. It has been suggested by some conservationists that Komodo dragons should be released onto mainland Australia to serve as ecological proxies for Megalania, which could in theory help heal the heavily depleted ecosystems of the continent. While I personally find this to be an interesting endeavor, I doubt it will happen anytime soon considering the country's current political climate. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYf6ZkF_ReaydKjo__chD1W5z0TCC5rJOsxkjuLvsUORYS-qxjJTCp5kROq9MwwJVnzwGYbYj51cY8HcmXRWWUVlrrYJPv4SOI0vu1CWha5iA4GoGUGKaX8SrFLsF1Vdf84kljp7N1Aayy/s1600/Komodo_Island_north_aerial.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="266" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgYf6ZkF_ReaydKjo__chD1W5z0TCC5rJOsxkjuLvsUORYS-qxjJTCp5kROq9MwwJVnzwGYbYj51cY8HcmXRWWUVlrrYJPv4SOI0vu1CWha5iA4GoGUGKaX8SrFLsF1Vdf84kljp7N1Aayy/s400/Komodo_Island_north_aerial.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Komodo, the island from which the Komodo dragon gets its name</i></span></div>
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While it is a great shame that the giant Monitors of yore are now gone, the remains they have left behind allow us to gain a glimpse of the world they inhabited. Still poorly understood, and lacking any complete fossils, there is yet much to be learned about them. In time however, if we continue looking, we may very well begin to uncover more of their secrets, and bolster our understanding of these fascinating animals. I look forward to the day when our understanding has progressed to the point where I can confidently declare this post obsolete.</div>
Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com5tag:blogger.com,1999:blog-7897751509059623525.post-84776777482838132972015-08-28T11:37:00.000-07:002015-09-05T08:26:53.410-07:00The first Tyrannosaurs and how they livedEveryone knows Tyrannosaurus rex, the most famous dinosaur of all time. It is the only dinosaur commonly referred to by its scientific name(T. rex), the only dinosaur that you can be almost completely certain everyone you ask will have heard of, and one of the most well known large Theropods specimen-wise. But as famous as T. rex is, far fewer people have heard of its ancestors. Indeed, while Tyrannosaurus was a late Cretaceous genus, the Tyrannosaurids go back to the early cretaceous, and the Tyrannosauroid superfamily all the way to the mid Jurassic. It is the latter that we will be talking about today.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0oW4dxQcTGmDitUgX9WYtDr-ppLZi9Ig79yFdMpi2I-lrMxitS3xceV5R_J6nkQ9Yl02CvhujZM9pa_4BvpuMLwS0f9Z2D8KNibTuLr3j5C_J-rmro5HSNorWopOBvM3gUZEGP8Ta8vWj/s1600/Coelurus_BW.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="172" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh0oW4dxQcTGmDitUgX9WYtDr-ppLZi9Ig79yFdMpi2I-lrMxitS3xceV5R_J6nkQ9Yl02CvhujZM9pa_4BvpuMLwS0f9Z2D8KNibTuLr3j5C_J-rmro5HSNorWopOBvM3gUZEGP8Ta8vWj/s400/Coelurus_BW.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Coelurus by Nobu Tamura</i></span></div>
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The Tyrannosauroids were a wide group, containing many different lineages, among them the more derived late Cretaceous Tyrannosaurids. In this post however I will be covering only the earliest and most basal members of the group, the ones who are either directly ancestral to later species such as T.rex, or at least close to the ancestry. One of these species was Coelurus. While not a particularly impressive dinosaur in its own right, and only known from partial remains, Coelurus has the honor of giving name to the large group called the Coelurosaurids, which includes animals as diverse as Therizinosaurus and the Golden Eagle. Coelurus itself lived in the late Jurassic of North America, 150 million years ago. It inhabited the Morrison formation, where it shared its habitat not only with stars such as Allosaurus and Brachiosaurus, but also another early Tyrannosauroid, Stokesosaurus, which we will get to later. Given it's small size, at only around 2 meters in length, Coelurus would have been a diminutive part of the Morrison fauna, with a diet most likely consisting of Arthropods and other small animals such as Mammals.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKsn8ruvLHdmxz4z3BcjjGE6L-lVjBVrJ-E7egWhuxs3B82VWX-5joJA3qE7ioAUU6KPwsYTliq2eJ6QdKD6JTI88j61pisiWU8aXlyXSokjzYAoGaB5Lr9qWBkxT_IIYZiPPk5bcRXsmf/s1600/5326228016_ae63d1fe65_b.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="152" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjKsn8ruvLHdmxz4z3BcjjGE6L-lVjBVrJ-E7egWhuxs3B82VWX-5joJA3qE7ioAUU6KPwsYTliq2eJ6QdKD6JTI88j61pisiWU8aXlyXSokjzYAoGaB5Lr9qWBkxT_IIYZiPPk5bcRXsmf/s400/5326228016_ae63d1fe65_b.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Scene from the Morrison Formation, where Coelurus lived, by Doug Henderson</i></span></div>
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Another basal Tyrannosauroid was Aviatyrannis, a tiny animal, at less than two meters in length. Its fossils were originally referred to Stokesosaurus, but later made into their own genus when they were found to be distinct. Exactly where Aviatyrannis fits in the phylogeny of the Tyrannosauroids is uncertain, but it is currently viewed as a basal member. The genus is known from very few fossils, with the holotype consisting only of an ilium, which may have belonged to a juvenile. Another possible early Tyrannosauroid is Iliosuchus, though this is controversial, as it's bones are very similar to those of small Megalosaurids. If it was a Tyrannosauroid, it would have been the earliest one yet known.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVWYCExHIcZztxt1jtWT7xZ0FWUcv8kEAy5znYywGtTWeDD3ZNSWgEjgljdEQxoeoStBl6ED9r7PBzvaKnv2lLL1s4TQcHPYSO23b8qf-anZoHugeXYO45OWcVFpca-i3OMjOSQ6KdHID3/s1600/proceratosaurus_bradleyi_by_alexanderlovegrove-d919vzg.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="281" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgVWYCExHIcZztxt1jtWT7xZ0FWUcv8kEAy5znYywGtTWeDD3ZNSWgEjgljdEQxoeoStBl6ED9r7PBzvaKnv2lLL1s4TQcHPYSO23b8qf-anZoHugeXYO45OWcVFpca-i3OMjOSQ6KdHID3/s400/proceratosaurus_bradleyi_by_alexanderlovegrove-d919vzg.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>A pair of Proceratosaurs hunting, by Alexander Lovegrove</i></span></div>
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Moving on to another lineage of early Tyrannosauroids, the confusingly named Proceratosaurids were a group of primarily small animals, which contained Proceratosaurus, the earliest confirmed Tyrannosauroid. The Proceratosaurids were not in fact ancestral to the later Tyrannosaurids, but instead represent a side branch diverging near the base of the Tyrannosauroid tree. During the mid to late Jurassic they were the most successful Tyrannosauroids we know of, but shortly after reaching truly gigantic sizes with species such as Sinotyrannus, they finally went extinct in the early Cretaceous. The Proceratosaurids were interesting in that they all appear to have possessed elaborate head ornaments, a feature which was either ancestral to all Tyrannosauroids but then lost in most lineages early on, or more probably independently evolved in the Proceratosaurid lineage.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5SJlKRjmrEyMXX1RmGduwyqEzWPD0iN0dT2hZzvjk3QY3HcjnzDsJKK6ENXqw59Q9lORVI4ffJwYdixx-ApRWO8t_1pLY2Yv6TflsKfxF5KJms1ezaAxc16gVaxeP3D6nh8rqmcDmiewj/s1600/Guanlong_raul_martin.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="161" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg5SJlKRjmrEyMXX1RmGduwyqEzWPD0iN0dT2hZzvjk3QY3HcjnzDsJKK6ENXqw59Q9lORVI4ffJwYdixx-ApRWO8t_1pLY2Yv6TflsKfxF5KJms1ezaAxc16gVaxeP3D6nh8rqmcDmiewj/s400/Guanlong_raul_martin.jpg" width="400" /></a></div>
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<span style="font-size: x-small;"><i>The Proceratosaurid Guanlong by Raul Martin</i></span></div>
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Proceratosaurus was the earliest known member of its group, and may have represented the basal form of all Proceratosaurids. It was a fairly small animal, about the size of a wolf, and lived in the mid Jurassic of England, 165 million years ago. The reason for the species, and subsequently group's name is that it was initially thought to have been ancestral to the Carnosaur Ceratosaurus, due to what appeared to be a similar nasal crest. More complete finds from other Proceratosaurid species have since showed that the crest was probably much more elongated than that of Ceratosaurus, stretching from the tip of the snout to the back of the head. Proceratosaurus was closely related to another genus named Kileskus, which was a contemporary living in Russia. It probably possessed a similar crest, and was about the same size. More significant was Guanlong, a Chinese relative from the late Jurassic. This animal is known from far better remains than its two relatives, to the point where we have even found fossils of animals from various stages of growth, showing the development of the crest over time, and the age at which the animals matured. </div>
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<span style="font-size: x-small;"><i>Juratyrant by Nobu Tamura</i></span></div>
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The last two Jurassic Proceratosaurids were Juratyrant and Stokesosaurus. The former was a relatively large animal from the late Jurassic of England, 149 mio ago. It may have reached around 5 meters in length, which would have made it a medium sized predator for its time. It may have shared its habitat with Ceratosaurus, which is known from the nearby islands of Portugal. Stokesosaurus was, as mentioned earlier in this post, a North American animal, living in the Morrison formation in what is now Utah, alongside Allosaurus, Stegosaurus, and Coelurus. At the time it lived, Utah had a climate vaguely similar to today, with distinct wet and dry seasons. Many of the bones of larger animals in the formation were carried from the drier uplands into the swampy lowlands by streams and rivers, where they were preserved. Considering its size and the other animals of it's time, Stokesosaurus may have hunted small dinosaurs and primitive birds, which were beginning to appear by then.</div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com0tag:blogger.com,1999:blog-7897751509059623525.post-43337049607853546702015-08-27T12:24:00.000-07:002015-09-05T08:27:15.937-07:00On Hateg IslandHateg Island is undoubtedly one of the most important European faunas from the Cretaceous. Many well preserved remains have been found here, and the animals which lived on the isle are textbook examples of how odd insular ecosystems can be. It can be difficult to predict just how life on the island was, as there are no analogous locations today, but in this post I will do my best to try and explain just how the ecosystems of Hateg Island may have worked.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAARYPgdg2mw8Q5npDmF0kiQ61AAu944ztl_aBUEqtmPUG8GO9cSua4_c5nnrU4IAwb1I0vPFXcVZbr1EAg0WbEb2mbX-LWIl_D2n-b7bMK5Sod4ODGiH_qUEkm2jd1Amyjim410Vnl6C9/s1600/Hateg.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="241" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAARYPgdg2mw8Q5npDmF0kiQ61AAu944ztl_aBUEqtmPUG8GO9cSua4_c5nnrU4IAwb1I0vPFXcVZbr1EAg0WbEb2mbX-LWIl_D2n-b7bMK5Sod4ODGiH_qUEkm2jd1Amyjim410Vnl6C9/s400/Hateg.png" width="400" /></a></div>
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<span style="font-size: x-small;"><i>The Location of Hateg Island 90 mio ago</i></span></div>
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Hateg Island existed from approximately 100 to 66 million years ago, though it may still have been present in the earliest Paleocene. It was surrounded by the Tethys ocean, which covered most of Europe at the time. There is some uncertainty concerning the size of the island, but current estimates put it at 80,000 square kilometers. It was quite geographically isolated, more than 200 kilometers from the nearest coasts, which to the north was the Bohemian Massif, and to the south an island corresponding to the Balkan massif, meaning that interaction with the outside world would be minimal for any animals not capable of flight. The climate of Hateg was sub-tropical, with marked dry and rainy seasons, and an average temperature in the twenties. Lot's of material for seeds and berries has been found in the Hateg sediments, as has pollen for Birch, Walnut and Beech, giving us a good idea of the island's forest structure.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFyE7gghkpqxrCnDzWsP77vCmq_lzlflogzg6qXzOh6J6Fs5o5HUTF2ptP1_iraKcJg-P7ia4Tcrp2QizxgqIpieg4IYcfx60hKiPEVI-M-a3iI8UVxOt59R7Rx7BaW3FTA_hPrcFNW2Vf/s1600/21121532.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiFyE7gghkpqxrCnDzWsP77vCmq_lzlflogzg6qXzOh6J6Fs5o5HUTF2ptP1_iraKcJg-P7ia4Tcrp2QizxgqIpieg4IYcfx60hKiPEVI-M-a3iI8UVxOt59R7Rx7BaW3FTA_hPrcFNW2Vf/s320/21121532.jpg" width="320" /></a></div>
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<span style="font-size: x-small;"><i>Dry woodland similar to this would have covered much of Hateg Island</i></span></div>
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The most interesting part of Hateg, at least in my opinion, is however the fauna. While the initial animals from which the Hateg faunas descended from were probably quite typical for the time, the insular conditions caused them to develop in a very different direction from their mainland cousins. Much like the way Dwarf Elephants were once found on many islands, the terrestrial fauna of Hateg almost entirely consisted of island dwarfs. Probably the largest animal on the island was a Titanosaur named Magyarosaurus dacus, at 6 meters in length. Another large animal on the island was a Hadrosaur named Telmatosaurus, which could reach up to 5 meters. Both of these animals are still large compared to modern mammals, but downright tiny compared to their mainland counterparts, with some Titanosaurs being able to reach 30 meters. Other herbivores on Hateg included the Nodosaur Struthiosaurus and the two Rhabdodontids, Zalmoxes and Rhabdodon, with the later being particularly interesting in that it was also found on other European islands. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgB0EfCOCFkTDvkkYOeL0L33nqjbgmFD9R9cWBHUTdaGynwZTl_2OFSPGzsHT7DP6rXMq6t47TK9g9d5Q-QsrLAtPbu4hM9MB-1fvrMwg3gKXmvO6bNW6AKv5TJr2TQs1EblRjimEO12b_j/s1600/Rhabdodon_priscus.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="137" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgB0EfCOCFkTDvkkYOeL0L33nqjbgmFD9R9cWBHUTdaGynwZTl_2OFSPGzsHT7DP6rXMq6t47TK9g9d5Q-QsrLAtPbu4hM9MB-1fvrMwg3gKXmvO6bNW6AKv5TJr2TQs1EblRjimEO12b_j/s400/Rhabdodon_priscus.JPG" width="400" /></a></div>
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<span style="font-size: x-small;"><i>Wall mounted fossils of Rhabdodon</i></span></div>
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As with the herbivores, the Theropods of Hateg were also clearly insular species, with oddities such as Balaur bondoc, a possibly herbivorous dromeosaur-like flightless bird, Elopteryx, a nomen dubium known only from a few bones, probably from some form of Maniraptoran, Bradycneme draculae, an alvarezsaurid, and a Carnosaur who's relations are currently unknown. The apex predators of Hateg were not however Theropods, but rather members of another lineage of Archosaurs, the Pterosaurs. Hatzegopteryx thambema, a giant Azhdarchid, was by far the largest predator on the island, at around the size of a Giraffe. While probably unable to take down the adults of the larger herbivores, they would almost certainly have been deadly predators of juvenile animals and smaller species. Another species of Azhdarchid, Eurazdarcho, is also known from Hateg, along with a very peculiar short-necked genus that is currently unnamed. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgD-mzftkb26wL3Za-LcWa5mGaWmn-r66RBckhD6THDKMpmPng5szmcgQzZP6kzGPawHK15JFDPcvSwVm5L22Pjp7vaL04hqv6Ednj8IrSXCkle0yCQzmDtRT_dS8lfyC405C6Y64R19pIi/s1600/hatzegopteryx-m-witton-12-5-20081.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgD-mzftkb26wL3Za-LcWa5mGaWmn-r66RBckhD6THDKMpmPng5szmcgQzZP6kzGPawHK15JFDPcvSwVm5L22Pjp7vaL04hqv6Ednj8IrSXCkle0yCQzmDtRT_dS8lfyC405C6Y64R19pIi/s320/hatzegopteryx-m-witton-12-5-20081.jpg" width="193" /></a></div>
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<span style="font-size: x-small;"><i>Hatzegopteryx thambema by Mark Witton</i></span></div>
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In summary, Hateg Island really was a particularly odd and spectacular location, even by the standards of the Mesozoic. The concept of dwarf dinosaurs is a fascinating one, and with an island as large as Hateg, what we have is an entire ecosystem populated by them. Insular dwarfism is a familiar concept that we know occurs in modern animals, but Hateg Island played a key role in proving that these same evolutionary pressures also shaped dinosaurs and other prehistoric animals living on ancient islands. Our current knowledge of Hateg is still quite limited, and there are probably many more species waiting to be discovered, but even with our current understanding, what we find is an astounding lost world, unlike any other.</div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com1tag:blogger.com,1999:blog-7897751509059623525.post-30290880569782882912015-08-27T10:29:00.002-07:002015-08-27T14:42:07.236-07:00When Europe Was An OceanThe first post on this blog, let's see if this goes anywhere. When Europe Was An Ocean is both the name of the blog and this post, but it also refers to a specific span of time, namely between the mid Jurassic and Eocene. This is a time-span of approximately 120 million years, two times as much as the distance between the Holocene and the late Cretaceous. The world has obviously changed dramatically through this era, with the European archipelago being home to countless species, it's character drastically shifting over time. This post will be a short summary of the history of ocean-Europe, from it's inception to it's ultimate demise.<br />
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Our story begins in the late Jurassic of Germany, in the area now known as Solnhofen. The Solnhofen Limestone is renowned for it's well preserved late Jurassic fossils, giving us a fantastic insight into the area at the time. 150 million years ago, in the latest Jurassic, Solnhofen was part on an archipelago that stretched across much of Western Europe. A Shallow sea covered most of the area, dotted with small atolls and other islands.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjIkY86wQYs_WtP4TKl9GYuDVZyYdoYWPshzpwW2Q4cv0DgSk97_8E4DRWz4mpb0NhFpbbR29nNd7Xogf98Ig0toYzVCProQMSaZnd8M6oYbIy8GQqeEh8fd3BVIjJWLbIMLM3wjxL7aLD/s1600/BaaAtoll_DE-DE7307014258_1366x768.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="221" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgjIkY86wQYs_WtP4TKl9GYuDVZyYdoYWPshzpwW2Q4cv0DgSk97_8E4DRWz4mpb0NhFpbbR29nNd7Xogf98Ig0toYzVCProQMSaZnd8M6oYbIy8GQqeEh8fd3BVIjJWLbIMLM3wjxL7aLD/s400/BaaAtoll_DE-DE7307014258_1366x768.png" width="400" /></a></div>
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<i><span style="font-family: inherit; font-size: x-small;">What the Solnhofen Archipelago would have looked like</span></i></div>
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These islands were home to a diverse fauna, but one which included surprisingly few dinosaurs, probably due to their insular nature, and the flying birds not having evolved yet. In turn, they were inhabited by an incredible diversity of Pterosaurs, including animals such as Rhamphorhynchus, Aerodactylus, and even Pterodactylus, the first Pterosaur to be discovered. Two dinosaurs were present in the faunas however, both of them quite famous. One was Compsognathus, and another the perhaps more surprising Archaeopteryx, which while often portrayed as living in dense jungles alongside Allosaurus and Brachiosaurus, was actually an inhabitant of the European archipelago. Also present were several species of Crocodylomorphs, such as the small and terrestrial Alligatorellus, an Atoposaurid, and Geosaurus, a marine crocodile of the Metriorhynchid family.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjetiIOxY94SIXd1OBaxn509uUFdenBWVVIC3Iwnh427aiI8z6x6nWHqIUfwtU4LNp4uMVEaHLkNjlAvGOp1XNsrcuUXcojafL3k6G8FS2aJvQWvNeSi6fLIiDIHvZdMePbrV2r6hoST03J/s1600/Archeopteryx.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="292" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjetiIOxY94SIXd1OBaxn509uUFdenBWVVIC3Iwnh427aiI8z6x6nWHqIUfwtU4LNp4uMVEaHLkNjlAvGOp1XNsrcuUXcojafL3k6G8FS2aJvQWvNeSi6fLIiDIHvZdMePbrV2r6hoST03J/s320/Archeopteryx.png" width="320" /></a></div>
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<span style="font-size: x-small;"><i>Archaeopteryx lithographica, from Matthew Martyniuk's fantastic book, Beasts of Antiquity: Stem-birds in the Solnhofen Limestone</i></span></div>
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During the cretaceous, even as the continents were beginning to approach their current state, Europe continued to be a series of islands and microcontinents. While the smaller islands continued to resemble the Solnhofen archipelago, many of the larger ones had faunas more similar to those of the continents. One example of this is Britain, which was one of the larger isles at the time. All of the first dinosaurs discovered were from here, including Iguanodon, Megalosaurus, and Hylaeosaurus. Other well known british dinosaurs include animals such as the Spinosaurid Baryonyx and the Ornithopod Hypsilophodon. </div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKQf23dLMAiNB6dIANz_KDNgalpouRDMIQfNhrjr8j6i2NZGWCo76KgJWlmOa8S0k8PqRTOzaLYciU-K9oJHCOMODBiTda4Gs4cPgF9k3z5fojAYm-7oUyFt3ZBV6Kfd_hZAqbCuOTg2iw/s1600/post-10955-0-14887000-1410548766.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="266" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKQf23dLMAiNB6dIANz_KDNgalpouRDMIQfNhrjr8j6i2NZGWCo76KgJWlmOa8S0k8PqRTOzaLYciU-K9oJHCOMODBiTda4Gs4cPgF9k3z5fojAYm-7oUyFt3ZBV6Kfd_hZAqbCuOTg2iw/s320/post-10955-0-14887000-1410548766.jpg" width="320" /></a></div>
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<span style="font-size: x-small;"><i>A map of Cretaceous Europe, projected over a modern one</i></span></div>
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Another part of Cretaceous Europe that must be mentioned is Hateg Island, located in present day Romania. This large offshore isle was home to an incredibly unique insular fauna, such as the dwarf Sauropod Magyarosaurus and the Hadrosaur Telmatosaurus. The island was also home to at least a dozen species of small Theropods, but the primary predators on Hateg were in fact giant Azdarchid Pterosaurs of the genus Hatzegopteryx. These giraffe-sized animals would have been more or less uncontested, dwarfing all other animals on the island, including the sauropods. The Hateg faunas existed in the late Cretaceous, up until the K-PG extinction event.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQSdAYr6kt1u_SXyOzrVNnISLLcbp-8ycXzxAAtcZLxQZjnxZcusizVwcQwXGGxyka0qEgtIedUrUNCsOYPOwKIPMmpKNF2NXMxIt4OGHqKgXSS-8e6Fc5Yctd6vjGGH8H9LXhLE4jpd_V/s1600/Leptictidium.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjQSdAYr6kt1u_SXyOzrVNnISLLcbp-8ycXzxAAtcZLxQZjnxZcusizVwcQwXGGxyka0qEgtIedUrUNCsOYPOwKIPMmpKNF2NXMxIt4OGHqKgXSS-8e6Fc5Yctd6vjGGH8H9LXhLE4jpd_V/s320/Leptictidium.jpg" width="320" /></a></div>
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<span style="font-size: x-small;"><i>The small Eocene mammal Leptictidium, from Walking With Beasts</i></span></div>
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The Paleocene of Europe was a rather dim and poorly known time. Relatively few fossil remains are found from this period, but from what we know, it seems to have been populated by a very low diversity of species, a so-called recovery fauna, which slowly adapted and diversified in the time up until the Eocene. These early faunas were essentially composed of late Cretaceous species, but lacking any animals larger than a cat. For the first 10 million years, the orders of Artiodactyla and Carnivora had not yet appeared, though primitive primates were already present. When the modern groups first started to appear in the early Eocene, they would scarcely have been recognizable, as they had not yet settled into their modern roles. Hoofed, predatory Artiodactyls such as Dissacus stalked the undergrowth, along with other archaic groups such as the Condylarths. Interestingly, many of the larger animals during the Paleocene and Eocene of Europe were not in fact mammals, but instead members of multiple other lineages. Dinosaurs such as Gastornis, a large herbivorous bird, would have been some of the biggest animals in the faunas, and crocodiles would have been keystone predators.</div>
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpnGDG6s5XbJWMBeU0DGhYnocT4FerFA7ksh_dq6XQsOKvN3d9I6aluVNEgATTQ8ic3vDNpxLhYmzbeOD8wEzfzrPBeI168cfgHbEn1lgm0RLa0kAS_EOjJ50usdTTpeCsuoiACj1oUgDg/s1600/diatryma_gigantea_by_mattmart-d74yz22.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgpnGDG6s5XbJWMBeU0DGhYnocT4FerFA7ksh_dq6XQsOKvN3d9I6aluVNEgATTQ8ic3vDNpxLhYmzbeOD8wEzfzrPBeI168cfgHbEn1lgm0RLa0kAS_EOjJ50usdTTpeCsuoiACj1oUgDg/s320/diatryma_gigantea_by_mattmart-d74yz22.jpg" width="320" /></a></div>
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<span style="font-size: x-small;"><i>Diatryma, a North American relative of Gastornis, by Matthew Martyniuk</i></span></div>
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The Eocene saw a great diversification of mammals, as the faunas of the world finally recovered after the K-PG extinction event. In Europe, early Carnivorans such as Parodectes became widespread, though they remained small throughout the period. Other familiar animals, such as Bats and Pangolins also appeared, becoming common parts of the Eocene faunas. Other, far stranger animals were also present, and made up most of the megafauna at the time. Creatures such as the hippo-like Coryphodon and the first Perissodactyls arrived on the continent, due to a connection to North America through a land-bridge with Greenland. These early Perissodactyls were more primitive than either horses or rhinos, possessing features ancestral to both. The early Perissodactyls such as Hallensia were only the size of dogs, but increased substantially in size over the course of the Eocene. The first true horses to arrive in Europe were members of the genus Pliolophous, which may in fact have been a descendant of Hallensia. The mid Eocene was a very peculiar time, in which Europe was home to several lineages not typically though of as European, including Marsupials and the aforementioned Pangolins.<br />
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<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioIJVcC0C0aAg7S9xz-mrOLLecjTA0PtsNHIDWFwyFmiiX_4R0O0-Qxi3BV1nfsIMMk-TsOfIG9YmOOzrDdjYkuE7s_d6KQjJehZlm323OMImJ-YTMlKkfR-mPl0vdLGrTD63zHbclcT18/s1600/palaeotherium-magnum.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioIJVcC0C0aAg7S9xz-mrOLLecjTA0PtsNHIDWFwyFmiiX_4R0O0-Qxi3BV1nfsIMMk-TsOfIG9YmOOzrDdjYkuE7s_d6KQjJehZlm323OMImJ-YTMlKkfR-mPl0vdLGrTD63zHbclcT18/s1600/palaeotherium-magnum.jpg" /></a></div>
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<span style="font-size: x-small;"><i>Palaeotherium magnum, an archaeic Perissodactyl, related to tapirs and horses</i></span></div>
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By the late Eocene, the European archipelago was reaching it's end. The development of the first arctic glaciations was slowly causing the sea levels to lower, and the climate was getting colder. The dense, tropical jungles of the early to mid Eocene were gradually being replaced by more open, subtropical woods. Many surviving Paleocene lineages died out, and a faunal turnover began. Among the winners were animals such as Palaeotherium and Hyaenodon, and among the losers were groups like the Leptictids, which died out, leaving no descendants. The Gastornithid birds and terrestrial Crocodiles died out in Europe, and the Artiodactyls became one of the most successful groups. Then finally came the Oligocene, marking the end for the European archipelago, as a landbridge was established with mainland Eurasia, and masses of new species entered Europe. Many of these species had evolved in the more arid inland conditions of Asia, and were more well adapted to the drying climate than the insular faunas of Europe. Thus, a huge number of the endemic European lineages died out and were replaced by Asian immigrants, in an event sometimes called "La Grand Coupre". True Rhinos and Tapirs entered Europe, outcompeting many European herbivores, and several species of Hyaenodon went extinct, though a new species arrived from Asia, ensuring the genus' continued existence in Europe. Arboreal Primates disappeared from Europe, and the Creodonts, which had previously been top predators, steeply declined. Thus ended ocean Europe, and the continent began to take the shape we know today, though it would continue to look quite different for several million years to come. </div>
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Tristanhttp://www.blogger.com/profile/13451580709894555958noreply@blogger.com3