Temporal variation in hotspots and the effects of climate and landscape on wildlife roadkill along the BR-319: conservation challenges in a high-biodiversity area in the Amazon

Roads greatly impact wildlife, with roadkill posing a major threat to many species. In the Amazon, highways cut through biodiversity-rich ecosystems, exposing mammals, birds, reptiles, and amphibians to roadkill risks. Increasing traffic and expanding road networks drive population declines, influenced by environmental traits, traffic, and seasonal conditions. Temporal variation in these conditions can lead to shifting roadkill patterns over time, making it essential to understand how such changes affect wildlife mortality. Our study aims to identify temporal variation on roadkill hotspots and investigate their relationship with climatic (temperature and rainfall) and landscape (forest, agricultural, and wetland cover) factors. We used a roadkill database from the first 177.8 km of BR-319 (Manaus – Porto Velho) spanning 2017 to 2021 to evaluate variations in hotspots over time and investigate how those climate and landscape factors affect roadkills across different buffers (500 m, 1 km, 5 km, and 10 km). We recorded 673 roadkill incidents (107 mammals, 251 reptiles, 152 birds, and 163 amphibians). Hotspot patterns varied across years, with amphibians, reptiles, birds, and mammals showing distinct hotspot patterns. Climate and landscape factors significantly influenced roadkill rates, with higher temperatures correlating with more roadkill, while rainfall generally decreased incidents, and increased forest and water cover helped reduce roadkill across most groups. Our findings suggest that both climatic and landscape factors play crucial roles in shaping roadkill patterns, reinforcing the need to monitor changes over time and highlighting the need for context-specific conservation strategies along highways. In conclusion, mitigating roadkill along BR-319 will require integrated approaches that consider environmental variables, traffic management, and habitat protection to reduce wildlife mortality.