In the era of the Anthropocene, the environmental factors controlling the distribution and abundance of wildlife populations are increasingly complicated by historical and ongoing urban development and industrialization. The legacy of industrialization has enduring impacts on contemporary environmental quality, with additional downstream consequences for wildlife that reside in cities. However, industrial contaminants are not evenly distributed across or within cities. Further, while the long-term fitness consequences of environmental contamination are well-documented for most taxa, their effects on free-ranging wildlife at the population and community levels remain poorly understood. Here, we investigated whether environmental contamination risk from industrial pollutants was associated with mammalian diversity and mesocarnivore activity in the Seattle-Tacoma metropolitan area, Washington, USA, a historically industrialized region. Using camera trap data collected across 74 sites and pre-existing data from the Washington Environmental Health Disparities Map, we modeled environmental contamination risk, natural land cover, and human population density against mammalian community diversity, richness, and evenness. We also modeled activity rates of three common mesocarnivore species (coyotes, raccoons, and Virginia opossums) via the number of detections. We found that mammalian diversity and evenness decreased as contamination risk increased, especially in Seattle. Among mesocarnivores in Seattle, coyote activity was negatively associated with contamination risk, while raccoon activity was positively associated with contamination risk; opossums showed no response. However, in Tacoma, contaminant risk was not significantly associated with mammalian biodiversity or activity; instead, human population density emerged as the most important predictor, with a negative influence on coyote activity and a positive influence on opossum activity. Our results highlight the importance of considering the legacy effects of industrialization and their impact on environmental quality in urban wildlife camera trap studies, and the need for species- and city-specific approaches in understanding the role environmental quality plays in shaping urban wildlife communities.

Linear barriers pose significant challenges for wildlife gene flow, impacting species persistence, adaptation, and evolution. While numerous studies have examined the effects of linear barriers (e.g., fences, roadways) on partitioning urban and non-urban areas, understanding their influence on gene flow within cities remains limited. Here, we investigated the impact of linear barriers on coyote (Canis latrans) population structure in Seattle, Washington, where major barriers (i.e., interstate highways and bodies of water) divide the city into distinct quadrants. Notably, private allele analysis underscored limited interbreeding among quadrants. When comparing one quadrant to the next, there were up to 16 private alleles within a single quadrant, representing nearly 22% of the population allelic diversity. Our analysis revealed weak isolation by distance, and despite being a highly mobile species, genetic structuring was apparent between quadrants even with extremely short geographic distance between individual coyotes, implying that Interstate 5 and the Ship Canal act as major barriers. Lack of gene flow may stem from the perceived risk of crossing these barriers, as even despite the presence of structural connectivity features (e.g., bridges and underpasses), functional connectivity may remain limited. Urban areas provide refuge and resources for wildlife but come with tradeoffs, as evidenced by restricted gene flow and potential long-term impacts on population viability and evolution. This study advances our understanding of gene flow and its consequences in cities, a crucial component for bolstering wildlife conservation and management in rapidly urbanizing environments.