When you think of a great city like Chicago, you most likely think of its towering skyscrapers, its bronze sculptures like the Herald Square Monument, or perhaps its more than 4,000 miles of paved streets. But Menno Schilthuizen, Dutch ecologist and author of Darwin Comes to Town: How the Urban Jungle Drives Evolution, argues that there’s a lot more to a city than the parts built with steel and concrete; they are rife with thriving and quickly changing natural ecosystems that we are just beginning to understand.
To write his latest, Schilthuizen (Nature’s Nether Regions) traveled to cities around the world to learn more about how human activity is shaping the evolution of plants, animals, and insects that share our urban spaces. What he finds will amaze even the most knowledgeable of nature lovers. Human activity has changed the pitch of some birds’ calls, how some plants propagate, and even the color of one species of moth’s wings.
In this interview, Schilthuizen discusses the implications of our participation, often unwittingly, in natural selection, why it wouldn’t be wrong to think of cities as “natural” habitats, and what the future looks like for human and non-human species in the face of climate change.
What do you think will surprise your readers the most about how human activity has helped shape evolution?
What usually surprises people is that evolution can go that fast. But it’s simple really: if the “selection pressure” is strong (that is, if the benefit of being different is great), then evolution will go fast, especially in animals and plants that have short generation times like insects or herbs. And since humans tend to make huge changes in the environment, the evolutionary response is also likely to be swift.
I loved your assertion in the book that cities are “natural” habitats, that they aren’t as divorced from nature as many people seem to think. Can you expand on this idea for our readers?
It depends on how you define nature, of course. We often define nature as anything that goes on in the world without the intervention of people. In that sense, cities are divorced from nature by definition. But I don’t see any reason to define nature that way. Humans are one of the many animal species that inhabit Earth. Anything that these animal species do is natural, and the same applies to humans. If it is in our nature to build structures that house millions of individuals, then that makes cities just as natural a phenomenon as, say, coral reefs or ant nests.
Around the globe, city developers are beginning, somewhat, to consider sea-level rise and other effects of climate change as they design—and re-design—city landscapes. With their minds so focused on what might happen in the future, I wonder what will happen to the small ecosystems already thriving throughout our cities. Are these small, urban ecosystems at risk of being wiped out by developers who are more focused on the future than on the here and now?
I should think so. Nature planning is a contradiction in terms. Nature, whether urban or otherwise, usually thrives best if we refrain from any planning. The best urban ecosystems are the ones that assemble naturally in unmanaged, forgotten corners of the city, not in those parts of the city where urban greening is meticulously planned and monitored.
Your book seems to suggest that many non-human species will survive the Anthropocene by evolving to adapt to human activity. That’s a hopeful thought, but I wonder about the ethics of relying on nature to adapt to us. Shouldn’t we be thinking about how to limit the impact of our activity on wildlife? Why or why not?
Perhaps I am naive, but it always surprises me when I hear my book and its message described as “hopeful” or “optimistic.” To me, urban evolution is a fascinating biological process, worthy of more scientific attention than it has got until now. I don’t mean to suggest that we can “rely” on it for the preservation of biodiversity. A large majority of species will never be able to adapt to an urbanized environment and will go extinct or survive only in pockets of habitat that are not impacted by humans. To conserve those species we still need to preserve and expand those pockets of non-human environment.
How do you, a scientist, think about the future of human and non-human life on Earth, especially in the context of climate change? Are you generally hopeful? Or do you despair?
That very much depends on what we mean by “future.” On a timescale of centuries, Earth is going to see tremendous ecological changes due to global warming and habitat destruction. The latter is, I think, at least as disruptive as climate change. A considerable portion of the world’s biodiversity, especially rare and specialized species, will disappear. After that big wipe-out, it could well be that we reach some sort of new Anthropocene equilibrium with human populations steadily maintained at many billions and supported by managed, impoverished ecosystems. However, I doubt that such a steady-state can persist for many millennia. Normally, in ecosystems, species that become so dominant in such a short time go through boom-and-bust cycles. For us, the present boom may well be followed by a bust. Culture and knowledge may be lost, and we return to a pre-technological existence of small groups leading quiet hunter-gatherer lives in a world that has been restored to its former self. Personally, I find that a comforting thought. Although the bust-phase, in whatever form it may come, will be far from pleasant.
Darwin Comes to Town by Menno Schilthuizen
Published April 3, 2018
Menno Schilthuizen is a senior research scientist at Naturalis Biodiversity Center in the Netherlands and professor of evolutionary biology at Leiden University. He has written more than 250 stories, columns, and articles for publications including New Scientist, Time, and Science. He is also the author of three previous books: Frogs, Flies and Dandelions (2001), The Loom of Life (2008), and Nature’s Nether Regions (2014).
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Amy Brady is the Editor-in-Chief of the Chicago Review of Books and Deputy Publisher of Guernica Magazine. Her writing has appeared in Oprah, The Village Voice, Pacific Standard, The New Republic, McSweeney's, and elsewhere. Follow her on Twitter at @ingredient_x.