Urban ecosystems provide a wide variety of resources, and urban wildlife populations must successfully navigate these complex environments for survival. Raccoons (Procyon lotor) have been one of the most successful animals in navigating this complex, anthropogenically-altered landscape. Like many metropolitan areas throughout the United States, Saint Louis, Missouri, has a long history of race-based human segregation, which has included redlining-enforced housing access and has shaped the urban ecosystem into what it is today. The urban ecosystem of Saint Louis is cleaved into two distinct sub-ecosystems – North Saint Louis (NSTL) and South Saint Louis (SSTL) – separated by one major street – Delmar Boulevard. This ‘Delmar Divide’ divides the city, separating black from white, poverty from wealth, and resource-rich communities from resource-poor communities. Here, we use this segregation as a model system for examining the population dynamics of the urban raccoon and their parasites, the raccoon roundworm (Baylisascaris procyonis). To do this, we non-invasively sampled raccoons both north and south of the Delmar Divide, measuring the population genetic structure and quantifying the prevalence and mean intensity of infection before comparing these metrics across the city, using socioeconomic valuation as a proxy for race.
Results/Conclusions
We collected hair and fecal samples from more than 300 raccoons across the Saint Louis metropolitan area, from six parks north of and six parks south of the Delmar Divide. We found several surprising patterns. Allelic diversity suggests two largely non-overlapping populations of raccoons, with alleles present unique to the SSTL and unique to NSTL. Moreover, significant pairwise FST values suggest a lack of gene flow between most large parks and between parks in NSTL and SSTL, with a Mantel test showing no evidence of isolation by distance as a driving mechanism of this pattern, suggesting that racial segregation results in segregation between raccoon populations. This pattern of segregation extends to infection dynamics of the raccoon roundworm as well, with no significant differences in the prevalence and intensity among raccoon populations within city boundaries but significant differences in the prevalence and intensity between NSTL and SSTL raccoon populations. Much more work remains to fully evaluate the disparity between urban ecosystems and wildlife in NSTL and SSTL, and to examine the depths of environmental racism in this system, but our findings suggest that racism can shape landscapes and significantly alter population dynamics of urban wildlife.