This qualifies as a milestone book that has genuinely transformed my opinion and understanding of an important topic. The perspective the author provides deviates from conventional stances
of conservation efforts, I am thoroughly convinced by his view, and nothing is more interesting than different opinions! It's a delicate topic, and really requires reading the whole book to understand the author's perspective. There is also a tone of optimism that has become rare as awareness increases on the impact of humanity on Earth. More importantly, while the topic may seem to be on the very specific aspect of ecological conservation, it in fact acts as a window into human nature, morality, and cognitive biases that shape more broadly other, seemingly unrelated views of the world. At the same time, this book is less about ecological interventions per se, and more about what nature really is and how it really works, and why are thinking about it have been all wrong.
If you disagree with my review, read the book. While it tends towards repetitiveness, the arguments are very thorough, and there are lovely descriptions of natural environments throughout that make it all very pleasant. You don't need to be a professional anything to understand his point or enjoy the book.
The core argument is that nature is all about change, and our conservation efforts have been ignoring this, instead trying to preserve or restore some idyllic past. I was struck by how this parallels strongly with other "moral" discussions regarding modern attempts to restore human lifestyle (diets, exercise, cityscapes, etc) to some lost idyllic past, regarded as the "natural" and preferred state of humanity. The idea that the modern age is a corruption of the past is pervasive, and it turns out the same bias that leads us to imagine an optimal past state is extended to the nature surrounding us.
The fact is, nature is dynamic, evolution IS change, and we have been fighting it. The battlefront of this war on change comes in the form of defending areas from "alien" species. While the argument has always been that the arrival of these other species risks the extinction of the natives, this has only verified itself in a tiny percentage of cases; the vast majority of the time, the new and the old live side by side. While we might be struck by the devastation of a parasite imported from abroad on a local population of chestnut trees in North America, we can easily loose perspective on how many other species have gone on entirely unnoticed as they creeped into the continent.
The book is optimistic, because it looks at nature differently. When you stop seeing alien species as intrinsically negative and invasive, especially when imported from humans, you realize that globally, things are doing all right; while we do loose many species to other human causes, nature is overall resilient to imports in a way that shouldn't be ignored.
The author argues that our tendency to spread other species all over the place recreates the conditions of archipelagos: lots of species get moved around, but end up in locations where they don't interact much, and yet aren't totally isolated from each other. This results in each "island" evolving their own characteristic species, but not so isolated that they don't feel the evolutionary pressure to maintain defenses against diseases, competition, and predation, thus resulting in biologically successful species. While at the moment we might perceive this spread of species as a tendency towards uniformity, the reality in the future will be an increase in species evolved for their new environment.
Not only should we not fight the movement of species, we could also consider actively moving endangered species to new locations where we suspect they thrive. This happens all the time, both with and without human involvement; a species that was close to extinction in some areas manage to spread to some new distant region where they thrive, thus avoiding extinction. Historically, humans actively trying to shape an ecosystem have failed spectacularly (e.g. introducing toads in Australia to eat bugs), or at least not had the desired consequences. This is different however from moving species to save them from extinction; they are less likely to be "invasive" given that they were close to extinction anyway, and presumably humans would try to save them because they liked them intrinsically, and whether they adorn American forests or Australian ones shouldn't much matter. I do not however consider myself qualified to make this judgement, I just would like biologists and ecologists to consider the possibility.
The only real quibble I have with the author is his attempt to redefine the term "natural". He argues that because humans evolved from nature, that makes everything they do "natural". The problem with this is that the reason we have the words "natural" and "unatural" at all is to very simply distinguish between things that were caused by mankind vs not. This is not the same as trying to argue that humans are in fact animals; animals are defined by their biological characteristics, and thus humans are animals. "naturalness" is defined as things not caused by human kind. While the line gets blurry, especially when moving back in time or when considering secondary consequences of human action, that doesn't mean the distinction is meaningless, just like distinguishing between species isn't meaningless just because there's a gradient of differences. A cement dam is "unnatural" and a beaver dam is "natural", just because humans did one, and non humans did the other. That's how language works, as well as cognitive categories.
Overall, this book gives you a new perspective on how to consider conservation efforts. It highlights the importance of defending actions that are sustainable in the long run (unlike saving disease prone flightless birds) and don't require constant intervention (such as leaving natural parks untouched). It over-stresses the point that animals moving around is a good thing, and the fact that we are behind it doesn't make it intrinsically negative.
halfway through the book, I thought this argument was a bit rich coming from a British landowner, a peoples with historical tendency to favor invasions; but unlike the Old British Empire, species that populate new places don't in fact make it a point of exterminating all the locals.
I was also struck by how the debate on migrant species paralleled the debate with handling migrant humans. Ironically, "liberal" ecologists tend towards defending native flora and fauna from invaders but cheerfully accept human immigrants, whereas their "conservative" counterparts tend to not care much at all if foreign plants and animals enter their borders, but do make a point of keeping out their human equivalent. The actual pros and cons of human movements vs animal and plants are quite different, and the same solution won't work for all, but it's still interesting that the debate isn't completely disconnected, and sometimes eerily similar stances crop up (albeit from different people in different times). For example, apparently there are attempts to cull bison around the Grand Canyon that have too many cow genes (how to go about this was not specified) because they are less "pure", which in my view got uncomfortably close to arguments of eugenics from Nazi Germany. It turns out, when we aren't paying too much attention, the same way of thinking crops up again and again, even if we should know better.
My other concern is that there is a little cherry picking going on. On the one hand, the author is specifically going over perspectives and information that is neglected by most ecologists, but it would have been more complete to paint an accurate picture of where the world stands. My only hint that there was such a bias came from when he mentioned Flanders, one of the most densely populated and agricultured region in the world, and where I happen to live at this moment. He used it as an example to say that he found just as many species in Flanders as he did in some part of the "wild" world, but he went to a veeeery limited spot here; the vast majority of this area is in fact farmland with only a handful of "wild" species finding any place at all to live. He also specifically mentioned bird species, which are in fact the only type of "nature" you can really see around here. There aren't even stray dogs or cats for how tightly controlled things are.