From beavers and bats to pocket forests and wetlands, the creative ways 6 cities are embracing nature

In London, beavers have been reintroduced after 400 years. In the Dutch city of Utrecht, the roofs of bus stops are now planted with moss to help support bees. In Delhi, India, multiple biodiversity parks are restoring small tropical forests within the city, home to wild boar, deer, and even leopards. In Haikou, China, a polluted river was freed from a concrete channel and the banks were replanted with mangroves and constructed wetlands.



Urban rewilding—reintegrating nature into cities—is growing quickly. At a time when more than a million species are on the brink of extinction, both because of habitat loss and climate change, adding greenery in cities obviously can’t solve the biodiversity challenge on its own. But inserting nature in concrete spaces can help, especially if cities plan broader green corridors that help wildlife move. And it can also help cities adapt to extreme heat and other climate impacts like flooding.



As megacities grow in Asia and Africa, there’s potential to better integrate nature from the beginning. “There doesn’t need to be a binary thing here, in terms of development or nature—I think there are ways to do both,” says Ben Smith, director for energy and climate change consulting at Arup, which just released a report with C40, a network of mayors, about rewilding in cities. Here are a few examples of projects shared in the report.



[Photo: Frédérique Ménard-Aubin]



Montreal: Frédéric-Back Park



In Montreal, a former limestone quarry and landfill is turning into a 378-acre park. The transformation, which started in 1995 and will be fully complete in two years, involved filling the space with thousands of tons of leaves and wood chips collected from the city and planting hundreds of trees and thousands of other plants. Birds, insects, and small mammals have returned to the site.



Medellín, Columbia: 30 Green Corridors



To help fight urban heat in Medellín, which sits in a valley next to the Andes Mountains, the city planted tens of thousands of native trees and other plants along a network of routes that cross between neighborhoods. The shade in these “green corridors” makes it more comfortable to walk, and also helps rebuild biodiversity in an area where green spaces have become disconnected.



[Photo: ©Wild West End/courtesy Arup]



London: Wild West End



In the middle of London, dozens of buildings have added green roofs, green walls, planters, and pocket parks over the last eight years, aimed at helping bring more birds, butterflies, and bats back to the area. Since the green spaces were added, species like the black redstart—a rare bird—have been spotted in the city.



[Image: Turenscape]



Qian’an, China: Sanlihe River Ecological Corridor Project



After decades of building new factories and a fast-growing population, the Sanlihe River in China’s Hebei Province was polluted. A new ecological corridor, which is 8.3 miles long, crosses the city of Qian’an. Concrete barriers were removed around the river, and a wetland was restored on the riverbanks.



Durban, South Africa: Buffelsdraai Reforestation Project



On the degraded land around a landfill in the South African city of Durban, the government paid unemployed residents to remove trash and invasive species and then plant more than 750,000 native trees and restore grasslands and wetlands. Birds and pollinators have returned to the area, and the project has also helped keep temperatures lower and prevent flooding.



[Photo: courtesy Cardim Arquitetura Paisagística]



São Paulo, Brazil: Floresta de Bolso



In São Paulo, landscape architect Ricardo Cardim planted a “pocket forest” in a backyard a decade ago, filling the space with native species in a pattern that mimics the way natural forests once grew in the area. Multiple other pocket forests have followed in other parts of the city, as volunteers clear concrete and trash, detoxify soil, and carefully plant trees like the giant jequitibá-rosa and grumixama, a fruit tree.



Arup says that certain factors help projects like these succeed, including governmental policies that support rewilding and partnerships between cities, community groups, businesses, and other stakeholders. If it’s possible to demonstrate that a project can help make a city more resilient to flooding or other impacts, more funding may be available. And it’s important to engage residents, the report says. “It’s not just about a single intervention,” Smith says. “It’s about building a community of people who care for this place for the long term.”