Estimating density of an elusive carnivore in urban areas: use of spatially explicit capture-recapture models for city-dwelling bobcats
An important first step in managing urban carnivores or the habitat in which they live to reduce risk of conflicts with humans is to understand their basic ecology and population dynamics. Traditional density estimators may be inappropriate in urban areas because of extensive areas of impermeable development but new techniques that include spatial structure could be useful within large urban metropolitan areas. Yet to date, these techniques have largely remained untested. We evaluated whether spatially explicit capture-recapture models (SECR) could provide a reliable density estimate of bobcats (Lynx rufus) in the Dallas Fort-Worth metroplex, Texas, USA. We obtained 1003 photographs of bobcats in an urbanized landscape from June–November 2014, using 41 double camera stations spaced approximately 1.05 km apart. We individually identified bobcats from their distinct pelage patterns and used SECR to predict density throughout the study area. The overall density was at least one bobcat per km2, which calculated to approximately 43 independent-aged bobcats across the entire camera grid, an estimate higher than documented bobcat densities in both rural and peri-urban studies in Texas. Our study revealed a high density of bobcats in an urban landscape despite most assumptions that bobcats require large areas of habitat and are sensitive to fragmentation.
KeywordsCamera trap Carnivore ecology Lynx rufus Population estimate SECR model
We thank the many technicians and volunteers who helped collect data and J. Draper for assistance with statistics and figures. We thank the editor and two anonymous reviewers for comments on earlier drafts. This study was funded by USDA-National Wildlife Research Center, Utah State University, the Welder Wildlife Foundation, Texas Parks & Wildlife Department, and in part, by USFWS Wildlife Restoration Grant W139 T2-4 and by in-kind contributions of Texas Parks & Wildlife Department volunteers. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the US government.
Compliance with ethical standards
This study was conducted in accordance with the USDA’s National Wildlife Research Center’s Institutional Animal Care and Use Committee (IACUC) regulations (QA-2211).
Conflict of interest
The authors have no conflict of interest.
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