Death in the Fast Lane: Assessing the Variables Surrounding Vehicle Caused Wildlife Mortality

Abstract

Roads segment Earth’s land surface into ~600,000 fragments. This habitat fragmentation leads to, unsurprisingly, frequent collisions with wildlife. Vehicle collisions are second only to legal harvesting in regards to anthropogenic mortality for numerous vertebrate species. In addition to increased mortality, roads can affect local hydrology, sediment and debris transport, water and air chemistry, microclimate and pollution. Variation in speed limits, road characteristics, weather conditions and fragmentation of existing contiguous habitats are expected to influence wildlife mortality. We hypothesized increased speed limits and roads bisecting developed and undeveloped land cover would lead to increased mortality. We used online data gathering application ArcGIS Survey123 to document and catalog instances of vehicle-caused wildlife mortality in Northern New York and Vermont. For 2023, two routes were driven regularly representing primarily forested and agricultural areas respectively. This was combined with a pre-existing dataset containing observations from across the country. Statistical analysis was undertaken in order to determine species distribution as well as how land cover type, speed limit, and road characteristics relate to wildlife mortality. Our study concluded that mammals accounted for the majority of animals killed on roads. Roadkill events occurred primarily in areas of low intensity development and mixed forests. Increased road speed appeared to correlate with increased mortality. Data from our 2023 sampling regimen parallels that of the national dataset. The most frequently found animals were the common raccoon (Procyon lotor), striped skunk (Mephetis mephetis), and Virginia opossum (Didelphis virginiana). This research allows us to see how continued development and habitat fragmentation is directly affecting wildlife populations in areas of human development.