A thought experiment in the Highlands

Much 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.

The British highlands as they appear today, beautiful but lifeless

Elephants 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.

Proboscidean cladogram, by Vladimir Nikolov

Exploring the natural land cover of Europe

How 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 here, 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.

Old-growth beech forest in Slovakia, often but mistakenly used as a model for all pristine European habitats

For All To See: Overgrazing apologists and regressive conservation

I have talked about the British highlands before, 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.

A picture of the desolate Scottish highlands, one of many in this post, with sheep in the foreground

Lands Pristine: Europe during the Eemian

Previously I have spoken about prehistoric Australia in great length, namely here and here, and recently wrote an in-depth post about ancient California. 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.

When people think of prehistoric Europe, they typically picture the early Holocene, covered here, 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.

Trafalgar Square, 130,000 years ago, by Roman Uchytel

A World In The Tar Pits: California before Humans

California 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.

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. 

Big cats of Europe - past and present

British 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.

An Eurasian lynx, the only real big cat left in Europe

Frozen in time: The illusion of stable ecological communities and the geological perspective

Evolution 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.

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.

Relict lineages and late surviving species

We 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.

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.

The early Holocene of Europe - from 11,000 to 6000 BP

The 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.

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.

Alien species and the future ecology of Australia

First 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.

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.

The Cattle egret, conqueror of the world

The world that we forgot

Humans 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.

The Cairngorms of eastern Scotland

Dawn of Dragons: The life and ecology of early Pterosaurs

Pterosaurs 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.

Hypothetical proto-pterosaur, by Mark Witton

Life and death in the Wessex Formation

The 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.

Polacanthus at a creek, by John Sibbick

A brief guide to the Paleocene faunas of Europe

66 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.

The Chicxulub asteroid impact, marking the end of the Cretaceous

Lizard Kings: The giant Monitors of prehistoric Australasia

Today, 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.

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.

Varanus priscus, by Vlad Konstantinov

The first Tyrannosaurs and how they lived

Everyone 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.

Coelurus by Nobu Tamura

On Hateg Island

Hateg 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.

The Location of Hateg Island 90 mio ago

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.

When Europe Was An Ocean

The 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.

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.

What the Solnhofen Archipelago would have looked like

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.

Archaeopteryx lithographica, from Matthew Martyniuk's fantastic book, Beasts of Antiquity: Stem-birds in the Solnhofen Limestone

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. 

A map of Cretaceous Europe, projected over a modern one

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.

The small Eocene mammal Leptictidium, from Walking With Beasts

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.

Diatryma, a North American relative of Gastornis, by Matthew Martyniuk

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.

Palaeotherium magnum, an archaeic Perissodactyl, related to tapirs and horses

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.