Unveiling patterns of roadkill of a migratory amphibian in Hong Kong with implications for mitigation

Road-related mortality, particularly wildlife-vehicle collisions, poses a significant threat to amphibian populations, with billions of individuals falling victim annually. The rapid urban development in Hong Kong, China, including the forthcoming construction of a "Northern Metropolis" area, is expected to bring over 2.5 million new residents, potentially increasing traffic and posing a heightened threat to local amphibians during their migration periods. To help prevent future biodiversity loss, our study focuses on the near-threatened newt species Paramesotriton hongkongensis in Hong Kong, investigating the spatiotemporal distribution of roadkill during migration seasons. Weekly surveys at four hotspots revealed 1,563 animal carcasses, the majority of which were P. hongkongensis. Factors triggering mass mortality events were explored, although no significant correlations were found. Prediction models demonstrated moderate accuracy in detecting mass mortality events, indicating a need for further refinement. Recommendations for site-specific mitigation measures to protect amphibians during their migrations are discussed, with an emphasis on the importance of conducting fine-scale surveys for effective conservation strategies.