There are myriad approaches to invasive species ¨C reflected in a similar number of terms, including ¡°alien¡±, ¡°non-native¡±, ¡°naturalised¡± and the like. At one pole is the notion that all non-native and invasive species are ¡°bad¡± for native biodiversity. Yet several recent books have taken the opposite line, that invasion has always occurred and is part of how ecological communities are formed, and so (within certain limits) we should celebrate the positives that new members can bring to our local patch. You have probably noticed the similarity to debates about national identity and immigration: we tend to be divided on whether the incomer should be celebrated or critiqued as likely to rock the familiarity boat.

The history of species invasion in the assembly and evolution of ecological communities is the topic of Tim Flannery¡¯s book. The introduction sets the narrative: Europe is special in that its position meant that it played a significant role in the evolution of ecosystems such as coral reefs and the cultures of man. The author appeals to the sci-fi enthusiast in all of us when he invites us to fly our Tardis back 100 million years to a series of islands ¡°east of Greenland, west of Asia¡±, sitting north of Africa and surrounded by ocean. (It¡¯s Europe, Jim, but not as we know it.) So we arrive in ancient eastern Europe, then a tropical island known as Hateg with white sand beaches, where, because of its isolated nature, it could support only dwarf herbivorous dinosaurs. Giant predatory flying pterosaurs were able to hop between islands feasting on miniature brachiosaurs, their ability to forage over larger areas enabling the evolution of their much larger bodies.

The island archipelago of ancient post-Jurassic Europe was not a geological hypothesis until it was proposed by someone Flannery would argue was one of the first palaeobiologists: Franz Nopcsa, a self-educated Hungarian polymath (1877-1933). We learn about the emergence of the study of ancient natural history and how nations have always been keen on publicly declaring the size of their dinosaur bones. Flannery weaves geology and biology into the history of developing societies and the emergence of conflict, both personal and militarised. He also conveys how annoying Nopcsa must have been while giving a clear sense of his intellectual brilliance and emotional fragility.

In chapter 5, we start to focus on the role of invaders in populating and diversifying Europe. Flannery paints a realistic picture, with tens of thousands of unsuccessful drowned island-hopping propagules for every success story of an ancient shrew or a cousin of a velociraptor gaining its red passport. When we think of ancient connections to the south, it is easy to restrict ourselves to the great rivers opening corridors across land masses before and during the retreat of ice from Europe, but this book pushes your event horizon further back to when great rivers flowed from Africa, bringing exotic fishes, the first amphibians, snakes and turtles to our shores.

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As the southern flow ebbed, movement along the northern De Greer corridor from the North American continent opened up. Flannery describes how Darwin¡¯s contribution to the theory of asymmetric competition (competition between individuals or species that are not equal, usually because one is larger than the other) explains how Europe¡¯s biodiversity was driven by donors and did not tend to donate species to other continents. This is because Europe¡¯s harsh conditions and small land masses and islands did not facilitate the evolution of large-bodied competitive species, although we are treated to the idea of such large dynamic species travelling across the globe using Europe as a set of stepping stones en route.

After the ¡°dinosaurotopia¡± of the Eocene epoch, we see a flurry of rather furrier invaders ¨C some large and some small, but mostly from the Americas. Fifty-four million years ago, the imprint of mammals on what will become our continent starts to take hold, although Europe also lost an important group that most likely evolved here: the elephant shrews. Flannery again describes not only the natural historical narrative but the lives of the people who helped to reveal our ancestral environments. He also draws on the work of Jerry Hooker at the Natural History Museum to describe the later Eocene invasions, when marsupials and early primates travelled into and across Europe from the Americas, while horses, camels and dogs crossed Europe on their way to the Americas ¨C none of which ended up in modern Europe without our later intervention.

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Europe: A Natural History?switches between fairly descriptive chapters about groups or species moving from here to there and there to where ¨C salamanders, toads, turtles, shrews, squirrels and various other reptiles are mentioned often ¨C interspersed with chapters concerning people and places to which we can more easily relate, such as the river in Nopcsa¡¯s Romanian estate. This switch is not only welcome but necessary. Indeed, the book would flow better if there were more personal stories and interjections of Flannery¡¯s own experiences and humour in each chapter.

Following two of the most fascinating sections on Europe as the ancient birthplace of modern coral reefs and gigantic marine gastropods revealed in sewer excavations in what is now Paris, Flannery leaves the smaller islands behind and we enter the much less fragmented landscape of continental Europe no more than 34 million years ago. Perhaps reflecting the success of science in elucidating less ancient history, the level of detail on invasion and speciation, as well as the pace of the text, now improves. Ancient pigs were top predators (and, given Europe¡¯s current lack of a range of extant carnivores, the same could perhaps be said of today¡¯s wild pigs). The giant forests of the Miocene lead us to the emergence of apes, although it seems strange to think that our continent was once much richer in primates other than ourselves. Ancient upright apes and hominids are supplanted by yet more invasions. The evolution of man is a most important element in understanding the formation, disassembly and reassembly of ecological communities in Europe ¨C and thus vital to the themes of this book.

Before we are halfway through, however, we shift from millions to tens of thousands of years ago and pass through the ice ages to the history of Europe that we think we all know ¨C that of wolves, bears, mammoths, Neanderthals and retreating ice sheets. But there is so much more, and anyone interested in natural history or wild Europe should enjoy, benefit from and be challenged by these latter chapters. Although the book was difficult to start with, it now gets very exciting. Perhaps this is from a combination of Flannery¡¯s writing skills and his reliance on the work of Luigi Boitani on how nature and humans can coexist on vast European landscapes. Some parts surprised me. Why, for example, is the loss of some species and the gain of others portrayed with such negativity in relation to modern agriculture when extinction and invasion are clearly part of the development of Europe throughout its otherwise very natural history?

Flannery was always planning to challenge us as he completes his final journey in his Tardis. Despite my own bias about rewilding ¨C ¡°aversion¡± might be a better word ¨C I found this challenge positive and suitably optimistic. I won¡¯t spoil the details of his vision for you, but they certainly suggest that we may be missing out on much more exciting opportunities by framing the future of Europe¡¯s natural history solely in terms of whether to have more lynx or wolves.

Tom Cameron is an animal ecologist who lectures at the University of Essex and seeks to understand how animals and the ecosystems they live in respond to change ¨C whether fishing, harvesting or climate variability. He tweets @ecoevoenviro.

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Europe: A Natural History
By Tim Flannery
Allen Lane
368pp, ?25.00
ISBN 9780241358078
Published 4 October 2018

The author

Tim Flannery, a professorial fellow in the University of Melbourne¡¯s Sustainable Society Institute, is a leading mammalogist, palaeontologist, explorer and conservationist who was voted Australian of the Year in 2007.

He was born in Melbourne in 1956 and studied English and history at La Trobe University and then earth sciences at Monash. He went on to a PhD at the University of New South Wales, where he described a number of new kangaroo species.

Yet his ¡°real education¡±, he says, ¡°came from the tribal elders I worked with over 20 years¡±, which led to his landmark book, Mammals of New Guinea (1990). ¡°These knowledgeable and generous ¡®professors¡¯¡±, he adds, ¡°taught me as much about leadership and compassion as about the unique mammals of their forests.¡±

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The author of books such as The?Weather Makers: The History and Future Impact of Climate Change (2005) and Atmosphere of Hope: Searching for Solutions to the Climate Crisis (2015), Flannery has in recent years divided his time between academia and activism.

¡°One informs the other,¡± he explains. ¡°In academia, you gain knowledge. But I have a strong urge to apply it to better my society, and this leads to activism. I am now comfortable in the role of ¡®public academic¡¯ that this entails.¡±

So what are the links between the very long view he has developed in his new book and the need for urgent action to address climate change?

In the long term, says Flannery, ¡°every trace of us as individuals (unless we are the lucky one in a billion to become a fossil) will be obliterated and the evolutionary process will restore nature¡¯s balance. But in the short term, as we upset that balance, we call down catastrophes upon our heads. The speed and scale of current climatic changes exceed anything faced by our species in its history. Unless we act to slow it, we as individuals will face severe consequences.¡±

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Matthew Reisz