Coastal fauna under threat from roadkills: A case study in southeastern Brazil

Animal collisions serve as key indicators of the impacts of roads on biodiversity. However, existing records and predictions of roadkill susceptibility predominantly focus on large inland roads and terrestrial species, overlooking its broader impacts on diverse ecosystems and coastal fauna. The objective of this study was to evaluate whether spatial and temporal factors influence the risk of animals being road-killed on a coastal road in Southeastern Brazil. The road was monitored from August 2021 to January 2024 over a stretch of approximately 8 km. The search for animals on the road was conducted at night using a vehicle traveling at ∼20 km/h. Each animal encounter was georeferenced to measure satellite-based variables including the level of urbanization, artificial light, shoreline tree coverage, beach width, coastline retreat tendency, tide range, air temperature, precipitation, and wave height. A total of 250 animals were found, including nine opossums, six birds, three snakes, one bat, 47 sea turtle hatchlings, and 184 ghost crabs. According to the Generalized Linear Model with binomial distribution, the risk of ghost crabs being road-killed was significantly higher in areas more affected by erosion, and during storm wave events. These results provide evidence that coastal roadkills are intensified by the loss of refuge habitats, a key characteristic of the coastal squeeze phenomenon. To minimize wildlife collisions on coastal roads, it is recommended to close roads during storms mainly in areas affected by erosion, build wildlife crossings, install signs indicating the presence of fauna, and implement public awareness programs in the region.