Landscape and population drivers of ungulate-vehicle collisions in Portugal

Ungulate-vehicle collisions (UVC) have been steadily increasing throughout Europe, posing a risk to human safety, representing an extra factor of animals death. Here, we used information of a 2-year roadkill (2019–2020) monitoring of wild ungulates (wild boar, red deer and roe deer) to assess the drivers that influence the likelihood of UVC in Portugal. Our results support the contention that the variables promoting the collisions varied markedly between species, including the importance of land use and cover (wild boar and red deer), water availability and movement corridors (wild boar), ungulate population density (wild boar) and road topology (wild boar, red deer and roe deer) in the likelihood of UVC. The significant and positive interaction between urbanized and forest areas shows that regions sharing characteristics of both urban and natural environments represent a high-risk for the occurrence of collisions. The application of mitigation actions in these regions are welcome and should focus on reducing its attractiveness and/or the abundance of ungulate populations. Awareness campaigns and species-specific signalling may also contribute to a general decrease of casualties. We advocate that continued efforts of data collection are pivotal to assess the local relevance of fine-scale predictors amenable to manage.