We don’t typically think of the city as a likely habitat for natural life — save rats, roaches and pigeons (but more on them later) — let alone as a hiding place for an undiscovered species of bird. But a new paper, published last week in the Proceedings of the Royal Society B, belies that notion. A team of 24 researchers has surveyed birds and plants in 147 cities, and found that cities much more closely resemble their native habitats than they resemble each other. The flora and fauna of East London, for example, would be more familiar to a farmer who had lived on the Thames a thousand years ago than to a modern-day visitor from Brooklyn or Hong Kong. While this might seem like a minor discovery to some, it’s one that actually forces us to reconsider the environmental impact of the city.
The idea for the study was simple: Compare urban data on plant and bird species with range maps to see how closely a city reflects its ecological birthright. (Anything intentionally planted doesn’t count.) With help from University of California Santa Barbara’s National Center for Ecological Analysis and Synthesis, the researchers compiled the largest-ever global data set of urban birds and plants, from cities in 36 countries and on six continents.
What the researchers found was a stunning level of native diversity in cities. The median city in the study has about 110 species of birds, of which over 95 percent are considered native; and 766 species of plant, 70 percent of which would have been growing there before urbanization. Ecologically speaking, cities are not replicable, concrete monoliths. Rather, each has a unique “bioprofile” — a kind of ecological fingerprint — that belies the notion of an environmental dead zone.