Most people think of segregation as a social phenomenon. But a Cary-led special feature in the journal Proceedings of the National Academy of Sciences examines how segregation also has deep ecological legacies that shape things like access to water, safety from floods, and exposure to extreme heat. To foster equitable cities, Segregation and Urban Ecology emphasizes the importance of understanding urban spaces as social-ecological systems to break cycles that reinforce segregation and its harms.
Urban ecologist Steward Pickett , a scientist emeritus at Cary Institute of Ecosystem Studies , organized the special feature together with Cary Research Fellow and NYU professor Timon McPhearson . Pickett explains, "Segregation affects who has access to safe housing, green spaces, climate protections, and other environmental benefits. While these inequalities are deeply rooted in historical and ongoing patterns of segregation, they are not inevitable. There are steps we can take to help ensure that ecological improvements benefit all communities — not just those who are already advantaged."
McPhearson added, "If you're doing work in urban systems, you can't ignore segregation because it's a big part of the social, economic, spatial, and power structures in any place where people live."
The special issue brings together ecologists, sociologists, planners, and other urban professionals. In an introduction and seven accompanying papers, they unravel how segregation takes root and evolves over time, the forms it takes in different environments, how its legacies and current forces impact modern communities, and how to begin repairing its damages. The authors hope the series of papers will help to set a research agenda for incorporating segregation as a factor in urban ecology and related fields, as well as spur novel solutions that break the cycle of segregation and support more equitable, biodiverse, and resilient cities.
Segregation: Alive and well, but ecologically understudied
Urban ecologists must consider segregation because of its impacts on environmental quality, human wellbeing, and power dynamics, Pickett and McPhearson note in the introductory paper. Segregated communities are more likely to be located near landfills, polluting facilities, industrial waste storage, and similar hazards, but less likely to have easy access to parks and the benefits of urban nature . They are often at greater risk of landslides, flooding, or severe impacts from hurricanes.
Furthermore, the authors note that segregation continues to affect policies and planning around climate adaptation, urban greening, and disaster risk reduction. When the legacies of segregation are ignored, decision making and urban planning measures can worsen existing inequities .
"Despite significant research in the last decade or so on social and environmental justice," said McPhearson, "some researchers in ecology, geography, sustainability, and related disciplines have yet to fully engage with the historical and present-day segregation processes that continue to drive social and ecological life in cities."
According to Pickett, segregation and its impacts are largely overlooked in favor of more measurable factors such as the physical and biological environment. "In an ecology class, they might talk about air, water, soils, nutrient cycling, and energy flow. But what's not often on that syllabus is power — and power differentials are driven by race and class, access to opportunities that generate wealth, and other social hierarchies. This stuff needs to be included in ecology textbooks. Because if we don't understand how something works, then we can't begin to repair it."
The tangled web of segregation
The papers in the special feature — detailed below — highlight how segregation is deeply entangled in the political, economic, and ecological processes of modern cities. They show that segregation influences flood exposure, biodiversity, infrastructure resilience, and sustainability decision making. The papers also emphasize the need for more inclusive planning, integrated infrastructure governance, equity-oriented climate adaptation, and knowledge co-production with marginalized communities.
Conceptualizing Racial Inequalities and Injustice in Social-Ecological Systems: A Foundation for Ecology of Segregation , by J. Morgan Grove and Steward T.A. Pickett
This paper explains how ecology can help us understand why racial inequities persist over time. The scientists use examples from Baltimore, Maryland, to show how zoning decisions, tree planting, and the siting of undesirable facilities shape and reinforce environmental inequalities. Segregation functions as a dynamic and resilient social-ecological system , the authors note, with lags and legacies that maintain inequity.
From Past, Persisting, and Consolidating Ecologies of Segregation to Ecologies of Repair , by Isabelle Anguelovski, James J.T. Connolly, Esteve Corbera, David N. Pellow, Fushcia-Ann Hoover, Jacqueline L. Scott, Marccus D. Hendricks, and Christopher J Schell
This team identifies five interconnected pathways — including under-greening, nature dispossession, and green gentrification — through which marginalized groups are systematically denied ecological benefits while being disproportionately exposed to hazards. The authors posit that degraded environments are both a result and a driver of segregation, reinforcing social exclusion, ecological harm, and disinvestment. They advocate for planning practices that integrate reparations, community-led solutions, and equitable green infrastructure.
Beyond Redlining: Gentrification, Displacement, Disadvantages, and Exclusivity Predict Urban Environmental and Health Inequities , by Idowu Ajibade, Kevan B. Moffett, Jason Maxfield, Kate Gregory, Axcelle Bell, Jackson Voelkel, Todd Rosenstiel, and Aaron R. Ramirez
Combining historical redlining maps and modern day market forces, this study looks at how neighborhoods in Portland, Oregon have evolved over time. Neighborhoods that have remained persistently privileged had more tree canopy, less dense development, lower disaster risks, better preventive care, and fewer diseases. Persistently disadvantaged areas faced the most severe conditions, including minimal access to nature, aging infrastructure, the highest pollution and hazard exposure, and the worst health outcomes and disability rates. Other neighborhoods experiencing gentrification and displacement had mixed outcomes. The study shows that segregation is dynamic, shaped by modern market forces, and not always aligned with past redlining maps, underscoring the need to examine how urban areas change over time.
Multiple Drivers and Long-term Patterns of Ecology of Segregation in Latin America , by Elizabeth M. Cook , Jason Sauer, Karin Weil González, and Olga Barbosa
Cary Institute's Elizabeth Cook and coauthors explore how the ecology of segregation can be applied in the Global South, specifically in Latin America, using Valdivia, Chile as a case study.
"Valdivia is a city of wetlands located in a biodiversity hotspot. It has a complex history that makes the access to and value of those wetlands and other green spaces very inequitable," Cook explained. With colleagues, she examined three different historic social and ecological drivers of segregation in Valdivia, starting with colonization and the displacement of Indigenous Mapuche communities. They observe that a 9.5-magnitude earthquake locked in the patterns of segregation, and describe how the neoliberal policies from the 1970s Pinochet dictatorship, along with formal and informal development, continue to influence access and management of urban green spaces in the city.
To mitigate entrenched inequalities and foster sustainable development, the authors call for inclusive urban planning, with community-driven approaches and the acknowledgment of Indigenous perspectives.
Expanding Frameworks: Integrating Vulnerability, Exposure, and Critical Infrastructure to Assess Pluvial Flood Risks in New York City , by Pablo Herreros-Cantis, Timon McPhearson , Bernice Rosenzweig, Malgosia Madajewicz, Elizabeth M. Cook , Veronica Olivotto, Evan Dennis, Franco Montalto, and Jennifer Cherrier
This paper demonstrates how segregation amplifies climate-related risks. Whereas most flood risk studies focus narrowly on the direct impacts of flooding and demographic exposures, this study incorporates social vulnerability and critical infrastructure. The authors identify multiple locations in New York City where there is both high flood exposure and high social vulnerability, emphasizing the need for equity-centered climate adaptation strategies in dense urban settings.
Housing Tenure, Climate Resilience, and Ecological Segregation , by Natalie M. Gulsrud, Oriol Garcia-Antúnez, Anton S. Olafsson, and Marina Bergen Jensen
Using a case study of a stigmatized neighborhood in Copenhagen, Denmark, this study demonstrates how climate adaptation policies applied as a one-size-fits-all solution ultimately exacerbate urban injustices. They show that stormwater management costs and risks fall disproportionately on residents in social housing, despite the city's reputation for equity.
Historic Residential Segregation Impacts Biodiversity Data Availability Disparately Across the Tree of Life , by Diego Ellis-Soto and Melissa Chapman
Historical redlining has produced enduring inequities in biodiversity data, according to this study. Analyzing nearly 60 million volunteer science observations across 195 U.S. cities, the authors find consistently lower sampling for plants, animals, and fungi in formerly redlined neighborhoods. The findings indicate that segregation shapes not only ecological conditions but also creates data blind spots that could potentially bias scientific conclusions and conservation decisions.
Diego Ellis-Soto spoke about this research at Cary Institute. Watch the video.
Future directions
The ecology of segregation as a coherent field is still in its early phases of development, and the authors of this special feature hope that it will inspire other researchers and scholars to move the theory forward. According to Pickett, there is still much work to be done. Among the outstanding questions put forward in the special feature are: Where have systems of segregation been broken or replaced, and how? What feedbacks could be shifted to break the vicious cycle of segregation and replace it with a more equitable system? And how can ecology as a field address segregation more directly and overtly?
"Much of the scholarship on segregation emphasizes its social and historical roots, but neglects how it affects ecological contributions to sustainability and environmental justice," said Pickett. "We hope our feature spurs additional research, innovation, and ultimately, practice, so we can expose and dismantle these previously invisible aspects of segregation."
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Cary Institute of Ecosystem Studies is an independent nonprofit center for environmental research. Since 1983, our scientists have been investigating the complex interactions that govern the natural world and the impacts of climate change on these systems. Our findings lead to more effective resource management, policy actions, and environmental literacy. Staff are global experts in the ecology of: forests, soils, freshwater, disease, and cities.
