Impact of Injury Caused by Snare Traps on the Space Use of Endangered Asiatic Black Bears in Taiwan

Abstract

Anthropogenic impacts, such as habitat degradation and overhunting, pose significant threats to wildlife populations globally. In Taiwan, alongside habitat loss due to urban development, the proliferation of snare traps has escalated threats to the locally endangered Formosan black bear (Ursus thibetanus formosanus), leading to increased bear mortalities and physical injuries. Despite the severity of these issues, there is limited information that can inform conservation strategies regarding the preferred habitat characteristics of the bears and the long-term behavioral impacts of snare-induced injuries. In this study, I evaluated movement rates, home range sizes, and habitat selection patterns of 15 bears (6 injured, 9 healthy) inhabiting Yushan National Park, Taiwan, to examine the impact of snare-derived injuries on bear space use. Further, I spatially predicted habitat quality across the system and compared quality within home ranges between healthy bears and injured bears. I did not find significant differences in diffusion rates and home range sizes, while I found that injured and healthy bears had different habitat selection patterns. Healthy bears preferred rugged terrain and greener areas, while injured bears exhibited no preferences for vegetation greenness and terrain ruggedness. Injured bears also showed stronger spatial avoidance of areas closer to roads with higher human activities, yet they did not temporally avoid human activities to the same degree that healthy bears did. These results suggest that injuries caused by snare traps could alter bears’ space use and possibly change the way bears react to human disturbances like roads. This behavioral impact potentially increases the encounters and risks from humans and impacts their energy gain in the long term. This study highlights that the impacts of snare traps extend beyond mortality and physical injury, possibly influencing the behavioral and energetic dynamics of bear populations, and necessitates strong regulations on snare trap usage to protect this locally endangered species.