Extinction, shrinking habitats spur Yale researchers’ ‘rewilding’ project in cities

DETROIT — In a bustling metro area of 4.3 million people, Yale University wildlife biologist Nyeema Harris ventures into isolated thickets to study Detroit's most elusive residents — coyotes, foxes, raccoons and skunks among them.

Harris and colleagues have placed trail cameras in woodsy sections of 25 city parks for the past five years. They've recorded thousands of images of animals that emerge mostly at night to roam and forage, revealing a wild side many locals might not know exists.

“We're getting more and more exposure to wildlife in urban environments,” Harris said recently while checking several of the devices fastened to trees with steel cables near the ground. “As we're changing their habitats, as we're expanding the footprint of urbanization, ... we'll increasingly come in contact with them.”

Animal and plant species are dying off at an alarming rate, with up to 1 million threatened with extinction, according to a 2019 United Nations report. Their plight is stirring calls for “rewilding” places where they thrived until driven out by development, pollution and climate change.

Rewilding generally means reviving natural systems in degraded locations — sometimes with a helping hand. That might mean removing dams, building tunnels to reconnect migration pathways severed by roads, or reintroducing predators such as wolves to help balance ecosystems. But after initial assists, there's little human involvement.

The idea might seem best suited to remote areas where nature is freer to heal without interference. But rewilding also happens in some of the world's biggest urban centers, as people find mutually beneficial ways to coexist with nature.

The U.S. Forest Service estimates 6,000 acres of open space are lost daily as cities and suburbs expand. More than two-thirds of the global population will live in urban areas by 2050, the U.N. says.

“Climate change is coming, and we are facing an equally important biodiversity crisis,” said Nathalie Pettorelli, senior scientist with the Zoological Society of London. “There's no better place to engage people on these matters than in cities."

In a September report, the society noted rewilding in metropolises such as Singapore, where a 1.7-mile stretch of the Kallang River has been converted from a concrete-lined channel into a twisting waterway lined with plants, rocks and other natural materials and flanked by green parkland.

Treating urban rivers like natural waters instead of drainage ditches can boost fish passage and let adjacent lands absorb floodwaters as global warming brings more extreme weather, the report says.

The German cities of Hannover, Frankfurt and Dessau-Rosslau designated vacant lots, parks, lawns and urban waterways where nature could take its course. As native wildflowers have sprung up, they've attracted birds, butterflies, bees, even hedgehogs.