Conservation of black bear (Ursus americanus) in Mexico through GPS tracking: crossing and roadkill sites

Abstract

Context Road networks are related to two global problems: habitat loss and degradation, and the decline of biodiversity. Wildlife roadkill is one of the most obvious and immediate impacts of linear infrastructure that affects all vertebrate groups, and some species, such as large carnivores, are more susceptible to fragmentation by roads due to their wide-ranging movements and home ranges. Aims Recently, black bear (Ursus americanus) sightings have increased in urban and suburban areas. The objectives of this study were: to identify and characterise road crossing sites used by black bears; to understand whether bears select specific landscape or road features for crossing; to compare crossing and roadkill sites; and to identify the most important variables in both groups to propose short-term mitigation strategies. Methods For the analysis of crossing sites, black bear individuals were captured from 2014 to 2018 and released with a GPS collar. We also calculated the dynamic model of Brownian motion to identify the road crossing sites. We obtained collision records from field work and government agencies. We performed Firth’s penalised-likelihood logistic regression models to identify the most important variables of highway or landscape in the probability of crossing or roadkill. Key results We captured 15 black bear individuals (11 males and four females), seven of which crossed a road at least once. Most of the crossings occurred during the night, which explains the results of the regression model between crossing and roadkill sites because crossings are a function of the percentage of buses and urban use. We also found that the speed at roadkill sites is significantly higher than at crossing sites. Conclusions This study contributed aspects necessary to understand the management of highways and reduce their impact on the black bear population in Mexico, such as the identification of priority mitigation sites. Systematic monitoring of roadkill in Mexico is required to propose specific mitigation sites that will benefit more vertebrate groups. Implications The information generated in this research forms the basis of identification of optimal sites for strategies to mitigate the bear–road conflict and help the conservation of the species.