台灣特有亞種猛禽之空間潛在威脅度評估

Spatial assessments of potential threats to endemic raptor subspecies in Taiwan

猛禽常出沒於人類活動範圍及周邊，為一種頗能適應人為環境的物種，但相對也承受著相當的人為干擾壓力。本研究選擇台灣特有亞種猛禽做為研究案例，包括鳳頭蒼鷹（Accipiter trivirgatus）、松雀鷹（Accipiter virgatus）、領角鴞（Otus bakkamoena）、黃嘴角鴞（Otus spilocephalus）及蛇鵰（Spilornis cheela）等，運用物種調查資料與最大熵（Maxent 模式）模擬各種猛禽之空間分布，另透過主成分分析整合人為干擾因子，即距離道路、建地及農地等最近距離，以及人口密度等變項，用以推估棲地威脅度，最終，再將以上結果進行套疊分析，可獲取各特有亞種猛禽所受到的潛在威脅度。研究結果顯示，領角鴞與鳳頭蒼鷹的分布面積，有超過 30%受到嚴重的潛在威脅，而本研究建構之流程，未來亦可應用於其他瀕臨絕種及珍貴稀有之生物，以提供物種的保育與經營管理之參考。 Raptors are able to adapt to a human-dominated landscape, but are often sensitive to direct human disturbances. We used the maximum entropy (Maxent) software to generate species distribution models of five endemic raptor subspecies using presence-only data for Accipiter trivirgatus, Accipiter virgatus, Otus bakkamoena, Otus spilocephalus and Spilornis cheela in Taiwan. We then combined anthropogenic disturbance factors such as distance to roads, built-up land, farmland, and population density to create a habitat threat map using principal component analysis. Finally, we mapped potential threats to each species through overlay analysis. The results showed that more than 30% of the distributions of A. trivirgatus and O. bakkamoena were located in ranges of a high threat level. Our methodology could be applied to any endangered and vulnerable species which requires impact assessment for future protection and management.

Raptors are able to adapt to a human-dominated landscape, but are often sensitive to direct human disturbances. We used the maximum entropy (Maxent) software to generate species distribution models of five endemic raptor subspecies using presence-only data for Accipiter trivirgatus, Accipiter virgatus, Otus bakkamoena, Otus spilocephalus and Spilornis cheela in Taiwan. We then combined anthropogenic disturbance factors such as distance to roads, built-up land, farmland, and population density to create a habitat threat map using principal component analysis. Finally, we mapped potential threats to each species through overlay analysis. The results showed that more than 30% of the distributions of A. trivirgatus and O. bakkamoena were located in ranges of a high threat level. Our methodology could be applied to any endangered and vulnerable species which requires impact assessment for future protection and management.