Scientists must recognize social inequality as a foundational ecological concern

For too long, ecologists and evolutionary biologists have not explored the relevant impacts of historical and current social inequalities on their field, thus inhibiting the possibilities for a justice-oriented approach towards conservation and restoration

Reviewed by Penny Sun


Cities are important ecosystems shaped by dynamic and interdependent biological, physical and social influences. However, Schell et al. note that few studies link research on urban ecological and evolutionary studies to that of social inequality. They argue it is integral to integrate these disciplines as human-created systems of power create uneven impacts on non-human ecosystems. And, ultimately, unequal distribution of green spaces and “blue spaces,” in addition to harmful practices, impact human health and well-being.

Historic and current social inequality is a particularly significant factor in urban ecology and evolution. Mechanisms of structural racism and classism including redlining and gentrification result from, and sustain, unequal distribution of resources and power. Unequal representation and power in decision-making impact the entirety of urban management, including development, governance, and infrastructure. The physical manifestations of these social inequalities also influence the distribution of biodiversity and evolutionary stressors, which affects the equilibrium of urban plant, animal, and microbe communities. Thus, research on ecological and evolutionary outcomes in urban settings must incorporate a social and environmental justice lens to adequately account for the drivers behind environmental change  and to advance goals of equitable urban conservation and climate resilience. 

Dr. Christopher J. Schell, PhD is an Assistant Professor in the UC Berkeley Department of Environmental Science, Policy, and Management. Dr. Karen Dyson, PhD is an urban ecologist at the University of Washington, the founder and director of Research and Design for Integrated Ecology, and Senior Scientist at Dendrolytics. Dr. Tracy L. Fuentes, PhD is a terrestrial ecologist and botanist and urban plant ecologist at the University of Washington. Dr. Simone Des Roches, PhD is a research scientist  at the University of Washington. Dr. Nyeema C. Harris, PhD is an Associate Professor of Wildlife and Land Conservation at the Yale School of the Environment. Dr. Danica Sterud Miller, PhD is an Associate Professor in the Culture, Arts and Communication division of the School of Interdisciplinary Arts and Sciences at the University of Washington. Dr. Cleo A. Woelfle-Erskine, PhD is an Assistant Professor at the University of Washington School of Marine & Environmental Affairs. Dr. Max R. Lambert, PhD is the Aquatic Research Section Manager at the Washington State Department of Fish & Wildlife.

Methods and Findings

To test several epistemological hypotheses, the authors summarize current cross-disciplinary findings on the socio-ecological implications of wealth disparities in cities, the impact of structural racism on urban structures and ecology, and the need for justice-oriented urban conservation approaches.

One of the key hypotheses is that household and neighborhood wealth – specifically median household income – correlates positively with urban biodiversity. This “luxury effect” is believed to occur because humans with greater resources available for non-essential needs have greater likelihood to facilitate growth and abundance of plant species in their neighborhoods. The luxury effect scales from the household to neighborhood and city level, with wealthier residential neighborhoods generally having more vegetation and canopy cover, plant diversity, and public park spaces than less affluent neighborhoods. Importantly, the distribution of plants within cities is inversely correlated with the concentration of heat and air pollution, resulting in urban heat islands and greater risk of exposure to air pollutants in lower-income neighborhoods. 

Wealth alone, however, does not completely predict urban ecosystem patterns. Structural racism, community norms, and local policies, are also predictors of urban socio-ecological patterns. Residential segregation policies based on racial prejudice, including redlining, have well-documented, measurable, and sustained harmful effects on urban ecological patterns that remain after official policies are dissolved. As a consequence, ecological and evolutionary stressors including heat, pollution exposure, and risk of zoonotic disease spread are not only distributed along economic lines, but also along minoritized racial and ethnic populations. Thus, the authors argue that urban conservation plans need to be tailored to the historical and contextual needs of the impacted communities, rather than applied uniformly across and within cities. 

The authors note that further research is necessary to better articulate the relationship between systemic racism, ecology, and evolution and to capture the intersectional effects of structural racism and classism on evolutionary outcomes. In addition, the authors identify a need to center Black, Indigenous, Latinx, and non-white immigrant communities in ecological and evolutionary research and justice movements due to their disproportionate vulnerability to the climate crisis and environmental exposure risk. These racialized groups experience the duality of environmental harm and social harm in public spaces including state-sanctioned police brutality. In addition, communities of color possess distinct environmental rights and relationships, cultural knowledge, and effective practices for ecological revitalization that have been historically, and detrimentally, excluded from urban environmental decision-making.


Ecologists, biologists, and environmentalists must expand the scope of their research and practice to include a social justice lens. Economic opportunity, public infrastructure, affordable housing, access to healthcare, and voting rights, are all powerful levers for promoting environmental justice, conservation, and local stewardship of urban ecosystems.

Centering social inequity in ecological and evolutionary research also enables equitable distribution of conservation and restoration resources and ultimately, urban biodiversity, according to community need. Researchers have a responsibility to integrate justice into their research process itself. This includes involving local communities in knowledge generation, increasing access to decision making, and eradicating practices of exploitation of community labor to produce academic discourse.

As the urgency of climate change grows, it is more important than ever to actively and radically dismantle systems of racial and economic oppression, within cities and outside their borders. Environmental and evolutionary biology research requires a thorough re-understanding and integration of the social factors impacting ecosystems to advance equitable urban resilience.


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