Monday, December 29, 2014

Cities are brimming with wildlife worth studying

https://www.sciencenews.org/article/cities-are-brimming-wildlife-worth-studying


By Kate Baggaley
December 29, 2014

Stanley Gehrt took a late-night drive to the cemetery on Chicago’s South Side. Its gate was locked, so he jumped the fence. In the trap he had set earlier, Gehrt found a young male coyote. He drugged it and carried it away.

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Since 2000, Gehrt has equipped more than 850 Chicago-based coyotes with ear tags or microchips for identification. He follows the movements of more than 400 of these coyotes using radio and GPS collars.

“When we started, we didn’t think there was going to be much of a study there,” he says. Coyotes usually need large, natural areas to survive, so he expected they would be scarce on the streets of the Windy City. “We were wrong.” He puts Chicago’s coyote population at about 2,000, although he suspects that there are probably many more.

Gehrt is not the first scientist to be surprised by how wildlife can flourish in urban habitats. Most people associate living things with pristine lands far from subways and parking lots, and consider urban territory to be a degraded, beat-up version of nature. But cities are fully functioning ecosystems, and humans are not their only citizens.

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their research has revealed some unexpected creatures thriving on land that people consider their domain. A few even serve as model citizens, quietly contributing their cleaning services to the benefit of city dwellers.

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He has found coyotes navigating abandoned railway lines, waiting for a stoplight to change and traffic to pause at congested intersections before crossing, and raising kits on top of a parking garage in the shadow of Soldier Field, home of the Chicago Bears. Leery of humans, city coyotes must wait until night falls to venture out to forage. During those limited dark hours, they patrol home ranges more than four times larger than they would need in the suburbs. Clogged with human settlements, city land offers fewer spots to find food.

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Like coyotes, bats have managed to thrive in cities, at least in Central Texas. Han Li, an ecologist at Baylor University in Waco, is investigating how bats use the varied urban landscape across the city. He records the bats’ echolocation calls, films them, and occasionally catches them in skeins of fine mesh called mist nets. Within the one small metropolis of Waco, he has identified eight of the nine bat species that inhabit Central Texas.

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When most New Yorkers sit on a bench to enjoy a steaming hot dog or a bag of chestnuts, they don’t think about what happens to the crumbs they inadvertently scatter on the ground. But ants and rodents devour much of the food dropped across the city; they may be earning their keep as a mini garbage service.

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New York also has tenants that are even easier to miss than ants, but might offer a different type of utility. McGuire, of Barnard College, has found a surprisingly wide diversity of microscopic fungi and bacteria on New York City’s green roofs, where plants and soil insulate the buildings beneath them and absorb storm water before it becomes runoff.

Many of these microbes are beneficial to plants growing in stressful environments — such as the shallow, nutrient poor, sun-drenched soil on Manhattan rooftops. The beneficial fungi snuggle in and on plant roots, growing filaments that search the soil for nutrients the plants require. In turn, the plants provide their resident fungi with sugars from photosynthesis.

Some of the fungi that McGuire identified in the soil are also thought to protect plants from pathogens and drought. Other fungi she found, among them species of Penicillium and Aspergillus, have the capacity to degrade certain pollutants, such as the hydrocarbons in car and factory exhaust.

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