DARWIN COMES TO TOWN

An appealing argument that “we must embrace and harness the evolutionary forces that are shaping novel ecosystems right here, right now, and work toward allowing nature to grow in the hearts of our cities.”

In this delightful account by Schilthuizen (Evolutionary Biology/Leiden Univ.; Nature's Nether Regions: What the Sex Lives of Bugs, Birds, and Beasts Tell Us About Evolution, Biodiversity, and Ourselves, 2014, etc.), the senior research scientist at Naturalis Biodiversity Center in the Netherlands, readers who assume that pigeons, cockroaches, and rats are the only representatives of city biology will learn that it is far more complex. Typical British mosquitoes feed on birds, mate in swarms, and hibernate during winter. When the London underground appeared 150 years ago, many moved down into the tunnels, adapted, and evolved into species that feed on humans, mate as individuals, and remain active throughout the year. Darwin believed that natural selection works too slowly to be observed, but this “drives home the fact the evolution is not only the stuff of dinosaurs and geological epochs. It can actually be observed here and now!” This is the first of a steady stream of ingenious examples and research results that bolster the author’s point that cities produce a unique, accelerated evolutionary environment. For example, birds adjust their calls to a higher pitch to be heard over the low-frequency roar of traffic. Awash with unfamiliar foods, shelters, and dangers, cities reward imagination, exploration, and problem-solving, so creatures normally shy in the wild become bold. The author points out urban ecosystems are becoming increasingly homogenized—e.g., 80 percent of herbs growing in the tiny islands of soil around street trees are identical to those in Europe.

An expert romp through urban natural history, which, despite the absence of glamorous megafauna, turns out to be a turbulent, hothouse ecosystem whose life is evolving before our eyes.