Conservation and Trapping News

Predicting coyote/coon/possum interactions in the Portland metropolitan area
Mar 7, 2022 16:27 ET

Abstract

Mesopredators—medium-sized predators such as coyote (Canis latrans), common raccoon (Procyon lotor), and Virginia opossum (Didelphis virginiana)—are common in urban spaces and live closely with humans. Recent studies in many parts of the world have found that mesopredator populations are expanding. The mesopredator release hypothesis has been used to explain this phenomenon, relating mesopredator expansion with declining apex predator populations. One top predator, the mountain lion (Puma concolor), has been steadily in decline in the western US as a result of urbanization and habitat fragmentation. Concurrently, the species richness and range size of many mesopredators has increased. To monitor mesopredators and other wildlife species in coordination with the nationwide Urban Wildlife Information Network (UWIN), we established 25 monitoring sites along a trans-Portland transect extending 50 kilometers from Hillsboro to Gresham. Motion-triggered camera traps were installed at each site. Site selection and data collection were both established in accordance with the UWIN camera trap protocol. During preliminary data collection from spring 2019 to spring 2021 we acquired occupancy results for three non-domestic mesopredator species: coyote (268 detections), common raccoon (218 detections), and Virginia opossum (406 detections). In this study, we will model the spatial occupancy of each of these three species in spring, summer, and fall 2021 as a function of landcover characteristics, sociodemographic factors, and other mesopredator occupancies. This analysis will allow us to determine which factors are most predictive of spatial occupancy for each species across the metropolitan region, supporting urban wildlife management and habitat connectivity goals.

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