Schubert, piano sonata in B flat, D.960.
This popular science book is a very interesting read. It describes the ecological history of North America from the time of the meteor impact that is thought to have caused the extinction of the dinosaurs, to the modern day. Before the arrival of humanity, about 13000 years ago, millions of years are summarised in about three chapters. Flannery’s title makes sense because North America has been a frontier for many different waves of invaders. Almost all of these came from Asia, but Flannery also describes how a number of new species came to North America when it joined up with South America.
Though it’s reasonably interesting to read about weird and wonderful ancient species and their movements (the world's crows and ravens apparently all come from Australia, for example), things do get more interesting when humanity makes its appearance. Until reading this book, I thought it was generally accepted that the mass extinctions of America’s ‘mega-fauna’ were caused by the newly arrived immigrants from Asia. But Flannery spends quite some time contrasting this theory with one which contends that the extinctions were caused by climatic change. It seems a pretty clear case to me. Just as lots of big species died off just as humans arrived in North America, so too did they in Australia. Within New Zealand, the Maoris killed off all the moa species within a few hundred years of their arrival. Even within the North American area, Flannery cites the case of Cuba where the mega-fauna only becomes extinct when the people arrive, some 6500 years ago.
Flannery then discusses pre-1492 North American history, and describes the varying ecological adaptations made in different parts of the continent. For example, it was really only in Mexico that intensive agriculture developed. In the Great Plains area, American Indians survived through hunting buffalo, which caused the buffalo themselves to evolve different behaviour patterns (grouping themselves into huge herds), which in turn had quite an ecological effect.
Finally, the Europeans arrive, and they do their bit to do as much ecological damage as possible. The buffalo only just survive, but the passenger pigeon, which used to fly in flocks so huge that they darkened the sky, get killed off by the end of the 19th century. Flannery also documents the apalling way that the latest batch of invaders treat the existing American Indian populations. He finishes with an interesting concluding chapter. He says that North America is particularly vulnerable to climatic change: its wedge shape funnels Arctic air southwards, a progress that is not interrupted by any east-west mountain ranges. So, North America had the world’s biggest ice sheets when the glaciers last rolled through, and has bigger responses to temperature changes than the rest of the world. Flannery also criticises a number of generally unsustainable practices and claims that North America’s treatment of its fresh-water resources is particularly bad.
This is the general thrust of the book, but one of its real strengths is that it’s beautifully illustrated by examples, ranging across a wide range of species, from horses to squirrels to snakes to deciduous forests. A fascinating book and definitely recommended.
Ian Stewart, Flatterland: like Flatland only more so.
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