The New Jungles; Think wildlife loves a country setting? Turns out that many animals, birds and plants now prefer the city.(Cover story)

Byline: Stefan Theil

A walk across the abandoned railyard in Berlin's Schoneberg district gives new meaning to the words "urban jungle." Between a noisy commuter train line on one side and apartment blocks on the other, a carpet of rare flowers with names like ladies' fingers and queen-devil hawkweed covers railroad ties and warehouse ruins. All sorts of endangered butterflies, spiders and bumblebees thrive, as does Europe's northernmost breeding colony of praying mantises. Goshawks and kestrels spy for prey overhead.

Nature has, of course, found its niches in towns and cities ever since humans built them. Pigeons and cockroaches have settled down with mankind. Escaped pets and their offspring, like the famed wild parrots of San Francisco's Telegraph Hill, have added an exotic touch to the urban fauna. Yet for some reason many of us continue to see cities as barren or worse, spreading biological destruction wherever they sprawl.

As they take a closer look, however, biologists in the nascent science of "urban ecology" are finding that cities are not just important habitats, but veritable hot spots of animal and plant life. "You can take any big city and find more species, more diverse habitats than in just about any national park or nature reserve," says Josef Reichholf, professor of ornithology at Munich's Technical University. Both in animal numbers as well as species diversity, he says, cities beat the countryside hands down.

Berlin, one of the best-studied cases, is home to two thirds of the 280 bird species existing in Germany, including peregrine falcons and ospreys--raptors that have disappeared from much of the country. What's more, biologists say, urban biodiversity seems to be on the rise--as our cities become cleaner, suburbs grow greener, and more and more species learn to adapt. These findings are challenging an old piece of orthodoxy--that urbanization is the planet's biggest environmental threat. On the contrary, it's in the open country that plants and animals have seen the most rapid decline. The main culprit, biologists say: a highly efficient but species-killing agriculture, now spreading from the developed world to southern countries like Brazil.

Vast "monocultures" of single-strain crops, maintained with powerful herbicides and insecticides, have decimated the older, more varied landscape. Many forests are now uniform tree farms supporting few species. An oversupply of fertilizers and animal wastes favors fast-growing greens that crowd out the wildflowers, grasses and weeds that were once a rich habitat for insects and animals. "The real wasteland isn't in the city, it's out in the country," says John Hadidian, head of the Urban Wildlife Program at the Humane Society in Washington, D.C. Today, biologists estimate that agriculture and forestry cause over 80 percent of explainable species deaths worldwide, versus just 15 percent caused by human settlement, pollution and sprawl.

Some biologists think flora and fauna are seeking refuge in cities, and the bigger the city, the better. For starters there are fewer guns (in general) and more sources of food in heavily settled areas, as suburban raccoons, deer and coyotes discovered long ago. In Zurich today, there are now up to ten times as many foxes, badgers and hedgehogs per square kilometer within the city as in the surrounding rural area, a recent Swiss survey found.