Effects of roads on animals and mitigation measures in Asia

Asia, the world's largest continent, boasts extensive road networks and rich biodiversity. However, the significant threats that roads pose to Asian ecosystems remain largely unaddressed. This study aims to provide a broad overview and insights into the research status regarding the effects of roads on animals and the implementation of mitigation measures in Asia through a comprehensive literature review, thereby filling a critical gap in global road ecology research. Following a systematic literature search and the establishment of inclusion and exclusion criteria, we included 589 publications, encompassing 36 Asian countries, while an additional 12 countries had no relevant publications included. From the included studies, we identified seven types of effects of roads on animals in Asia: road mortality, barriers to movement, road avoidance, various behavioral and physiological responses, habitat effects, illegal hunting, and road attraction. We compiled all documented roadkill data from pertinent research, resulting in approximately 208,291 roadkill records, including 1048 species, with 148 species classified as above Least Concern (LC) by the International Union for Conservation of Nature (IUCN). Asia has also implemented various mitigation measures. At least 155 species utilized wildlife crossing structures, with 39 species classified as above LC. Despite a considerable body of research in this field, there exists a notable imbalance in the geographical distribution of research across Asian countries and among the species that are the focus of research and mitigation. We propose several recommendations for future research directions in Asia, with many of these also relevant to future studies globally. • This study provides a groundbreaking comprehensive review of road ecology in Asia. • A total of 589 relevant publications were reviewed, encompassing 36 Asian countries. • Approximately 1048 species have been killed on Asian roads. • At least 155 species utilize wildlife crossing structures.