Science Is Revealing the Social Disparities at the Root of Urban Ecosystems

When it comes to biodiversity, research shows not all neighborhoods are created equal. They鈥檙e defined by injustices past and present.
People with binoculars walking in an urban park.
Front, from right: NYU researchers Rafael Baez, Emerald Lin, and Valentina Alaasam collect data with birders in Prospect Park. Photo: Sydney Walsh/约炮视频

On a cloudy September morning in Prospect Park, a massive swath of greenery amid Brooklyn鈥檚 concrete sprawl, the fall migrants are flying fast and furious. A group of birders spin excitedly in a clearing, calling out as new species appear. 鈥淲hat a hotspot,鈥 says Valentina Alaasam as she scribbles down each name in rapid succession: American Redstart, Scarlet Tanager, Black-and-white Warbler.

Alaasam will add the morning鈥檚 counts to a biodiversity database that she and her colleagues at New York University have been compiling for more than a year. The goal: to figure out whether parks in richer areas are also richer in wildlife. 鈥淚鈥檝e always been really interested in this concept of luxury effects, where neighborhoods that are wealthier tend to get more investment from the city, and more trees, and more green spaces,鈥 Alaasam says. To test how that may play out in New York, the team has been counting birds, bugs, frogs, and more across 11 city parks, including relatively well-maintained oases like Prospect Park and others that receive less upkeep.

The project will add to a growing body of research that鈥檚 revealing how economic and racial inequities shape urban ecosystems. In many cities, money has proven to be a major ecological boon: Wealthier neighborhoods host more of the street trees and that attract wildlife, while poorer areas have more uninterrupted concrete, leaving residents less likely to spot a flitting vireo or loping coyote. Yet such disparities didn鈥檛 pop up overnight, and in recent years, scientists have been peeling back the deeper layers that create these patchworks. 鈥淭he injustices that have shaped what we are today鈥攁s a nation, as a society鈥攁re shaping the entirety of the planet,鈥 says Christopher Schell, an urban ecologist at the University of California, Berkeley.

In 2020 Schell and his co-authors published an suggesting that biodiversity in cities was strongly tied to systemic racism. In particular, they argued, discriminatory federal housing policies known as redlining, though long abandoned, still shape local ecology today. Starting in the 1930s, federal housing agencies graded neighborhoods to inform whether banks should offer loans there鈥攁nd assigned lower grades to places where racial minorities lived. Residents in these areas, which were delineated in red ink to mark them as 鈥渉azardous,鈥 were then less likely to receive mortgages or local funding and more likely to watch their neighborhoods get torn up by highways or saddled with toxic pollution. 

Though the practice was outlawed in 1968, that legacy of segregation and disinvestment still echoes through American cities. 鈥淭hey鈥檙e no longer graded,鈥 says Chlo茅 Schmidt, an evolutionary ecologist at the German Centre for Integrative Biodiversity Research who has researched the effects of U.S. redlining. 鈥淏ut those environmental differences persist.鈥

Still, the patterns around wealth, segregation, and nature are not always simple.

Studies across multiple cities have found that areas deemed most desirable on the color-coded maps are greener today: They have nearly as redlined areas and are home to a of animal species. have shown that forest birds such as warblers flock to more affluent areas, while historically redlined communities mainly host classic urban dwellers like pigeons and sparrows. Meanwhile, Schmidt鈥檚 work has found that animal populations in minority neighborhoods have , suggesting they鈥檝e been fragmented by barriers like highways and may have more trouble adapting to environmental change.

Still, the patterns around wealth, segregation, and nature are not always simple, says Diego Ellis Soto, a conservation research fellow at UC Berkeley. His work has found that redlined areas tend to have in crowdsourced databases like eBird and iNaturalist. Scientists often use those tools to estimate biodiversity, so it鈥檚 possible they are overlooking species-rich hotspots. 鈥淚n some of these redlined neighborhoods, we have so little data that we can鈥檛 even talk about what lives there,鈥 he says.

Plus, the manicured habitats typical of areas deemed more desirable on old housing maps may even be less inviting for certain species, says Rafael Baez, a biology graduate student who is helping lead the New York project. Prospect Park is great for birds, but it鈥檚 Highbridge Park in Manhattan鈥檚 Washington Heights鈥攁 stretch of green along the largely Hispanic neighborhood, where Baez often finds park entrances blocked off and forest floor left untended鈥攖hat offers the rich layers of leaf litter and rotting logs that salamanders love.

As the team teases out these threads, Baez and Alaasam hope their findings can help inform park management and conservation efforts in New York, whether it鈥檚 developing green spaces in areas that haven鈥檛 gotten their fair share or recognizing and protecting rich habitats that have flown under the radar. In cities around the country, reckoning with our unequal history will be crucial to solving the biodiversity crisis and building a better path forward for people and animals alike, scientists say. 鈥淲e can鈥檛 just sweep everything under the rug,鈥 Schell says. 鈥淲e鈥檝e got to face our past if we want to have a future.鈥

This piece originally ran in the Winter 2024 issue as 鈥淭he Green Gap.鈥 To receive our print magazine, become a member by .