Roadkill risk model of black bear (Ursus americanus) in Mexico.

ABSTRACT

One of the most obvious impacts of roads is roadkill, a problem that is recently being addressed in Mexico. However, there are economic and human resource limitations to monitor the entire road network, assess its impacts, and propose mitigation measures. The black bear (Ursus americanus) is a top predator and the largest terrestrial mammal distributed in Mexico, currently the only of the Ursidae family. In recent years, its presence near human settlements and incidents on roads has increased. We generated a single MaxEnt model to identify characteristics of sites with high black bear roadkill risk and to identify these areas within protected natural areas. We obtained 83 bear roadkill records between 2008 and 2022, and we used a set of 16 variables that included landscape, road variables, and human variables. The model had an area under curve value of 0.96 indicating good performance and the Jacknife analysis identified influence on the roadkill risk of the distance to water bodies, protected areas, scrubland, drainages, and speed limit. We identified 3883.25 km of roads at high roadkill risk for black bears of which, 373.10 (9.6%) km were inside protected areas. We suggest placing speed bumps and effective signage on high-risk sections as a short-term, low-cost strategy. The results help to focus conservation efforts to specific sections of the road network, as roadkill is an increasing source of mortality that has not been evaluated for black bear in Mexico. This information is applicable for mitigating the impacts of existing roads and for planning new projects that have less impact on wild black bear populations and, at the same time, increase the safety of vehicle drivers.