Urban ecology, evolution, and racism

Occasionally, while reading the literature, you stumble across a paper that is so eloquent and beautiful that you are awestruck. Since that happened to me this weekend, today’s post is a call to you to go read the incredible synthesis and call to action written by Schell et al. in Science (2020) – The ecological and evolutionary consequences of systemic racism in urban environments. In this paper, the authors affirm that biologists working in urban environments must consider how racial oppression affects the biological change they study.

Lead author Dr. Christopher Schell.
For more info, visit his webpage – https://faculty.washington.edu/cjschell/wordpress/people/

Evolutionary biologists have increasingly become interested in how the environmental change due to urbanization leads to changes in the phenotypic, genetic, and species make-up of urban ecosystems. Indeed, between 1965 and 1989, only 124 papers with the words “Urban ecology” in the abstract were published according to a quick non-exhaustive search of Web of Science (mean = 5.0 papers per year; performed 8-31-2020). However, from 1990 until 2019, the rate of publication increased exponentially to over 1,000 papers in 2019 alone.

Scientists have begun studying urban environments for their own sake and also as a proxy for studying biological and evolutionary responses to novel, rapid environmental change. Urbanization modifies land surfaces, habitat connectivity, microclimates, food webs, species diversity, species composition, ecological networks, and ultimately ecosystem functions in the form of nutrient cycling, pollination, seed dispersal, food production, and air and water purification. The novel ecological conditions that result from human activity, like urban heat islands, environmental pollution, and trash-related food subsidies, drive changes in behavior, phenotype, genotype, demography, life history, species distribution, and ultimately community organization. To understand any of these aspects of a population, species, or community, we must understand what forces are structuring these urban conditions. The breathtaking Figure 1 from the paper illustrates this connectivity and the importance of understanding socio-cultural dynamics.

Conscious and unconscious systemic biases and stereotypes contribute to shaping institutional policies that drive and exacerbate racist and classist structures in urban systems (e.g., law enforcement, residential segregation, and gentrification). The emergent properties of these structural inequalities have profound impacts on multiple attributes across the urban landscape, including impervious surface cover, urban heat islands, green space and tree cover, environmental pollutants, resource distribution, and disease dynamics. These physical and biological characteristics have known impacts on the ecological patterns and evolutionary processes of urban organisms.

Researchers generally use socioeconomic status as a proxy for understanding how social factors, especially wealth, but also occupation, education, race, culture, and societal power influence ecology and evolution. The authors spend several sections discussing the pros and cons of using household and neighborhood wealth to explain ecological conditions. But this variable fails to explain many of the heterogeneity of urban environments and fails to account for the ways in which social inequality and inequity affect the people who are the primary influencers of the urban ecosystem. For example, racial make-up of a community can be a stronger predictor of the distribution of vegetation and canopy cover, environmental pollution levels and types, water quality and access, urban heat island effects, and proportions of native to introduced species. The authors then use the example of residential segregation globally and redlining in the USA to explore how ecological conditions are shaped by forces that cannot be characterized by measures like wealth. If you don’t know what redlining is, here is an excellent resource to get you started – https://www.npr.org/sections/thetwo-way/2016/10/19/498536077/interactive-redlining-map-zooms-in-on-americas-history-of-discrimination. See Figure 3 for understanding how racial segregation can affect ecology and evolution of individuals and species.

Critically for the time we are in, the authors discuss how racist practices in the drivers of urban ecosystem dynamics might drive links between pest population density and subsequent zoonotic disease transmission, compounded by the disproportionate negative health effects of environmental pollutants. Further, ecologists, biologists, environmentalists, and conservationists must re-imagine what we consider an environmental, conservation, or biological issue. To solve issues of climate change or environmental degradation, we must center racial and environmental justice because issues of racism are inextricably linked to the structure and make-up of the urban ecosystem (emphasis added).

To me, this the message of this paper was both radical and obvious, as it seems the best unifying principles often are. Radical because the largely white scientific connection has not made this connection before now, and obvious because if you’ve been paying attention to biological phenomena and principles and to the events of the last 6 months, the inclusion of societal inequality as a variable in urban ecology is a clear necessity. I am nowhere near as eloquent as the authors, so I leave you with the last paragraph and urge you to read the entire piece:

“Our capacity to understand urban ecosystems and non-human organisms necessitates a more thorough integration of the natural and social parameters of our cities. We cannot generalize human behavior in urban ecosystems without dealing with systemic racism and other inequities. Further, incorporating environmental justice principles into how we perform and interpret urban ecology and evolution research will be essential, with restorative and environmental justice serving as the foundation for effective ecological restoration and conservation. Doing so is both our civic responsibility and conservation imperative for advancing urban resiliency in the face of unrelenting global environmental change.”


Schell et al. 2020. The ecological and evolutionary consequences of systemic racism in urban environments. Science. DOI: 10.1126/science.aay4497

To read more about the lead author and his work, this is a great piece as well – https://magazine.washington.edu/feature/ecologist-christopher-schell-sees-himself-in-the-science/

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