Environmental contamination predicts mammal diversity and mesocarnivore activity in the Seattle- Tacoma metro area

Environmental factors controlling the distribution and abundance of wildlife populations in the Anthropocene are increasingly complicated by historical and ongoing industrialization. The legacy of industrialization has enduring impacts on environmental quality, with downstream consequences for wildlife. However, industrial contaminants are not evenly distributed across or within cities, and their effects on free-ranging wildlife at the population and community levels remain poorly understood. We investigated whether environmental contamination risk from industrial pollutants was associated with mammalian diversity and carnivore activity in the Seattle-Tacoma metropolitan area, Washington, USA, a historically industrialized region. Using camera trap data collected across 78 sites, we modeled environmental contamination risk, natural land cover, and human population density against several mammal community metrics and against activity rates of carnivore species. We found that mammalian diversity and evenness decreased as contamination risk increased, especially in Seattle. Across the metro area and within Seattle, coyote activity was negatively associated with contamination risk, while raccoon activity was positively associated with contamination risk; opossums showed no response. Within Tacoma, contaminant risk was not significantly associated with mammal community metrics or carnivore activity, but human population density had a negative influence on coyote activity and a positive influence on opossum activity. Our results highlight the impacts of industrialization in ecological processes, and the need for species- and city-specific approaches in understanding the role they play in shaping urban wildlife communities. Ecological studies that incorporate these impacts can inform urban planning and conservation strategies that improve environmental quality for urban wildlife populations.