以生物多樣性指標評估集水區崩塌地治理優選順序

The abundance of endemic species in Taiwan is a great natural treasure accomplished by a diverse altitude ranges due to violent tectonic activities and humid tropical weather conditions with ocean surrounded. With the characteristics of few flatlands, the slope lands are inevitable and have been developed for economic and social requirement gradually, which has caused habitation shrinking of animal and plant. Furthermore, Taiwan also suffers disasters such as striking of torrential rains and typhoons during summer season annually, and is vulnerable to landslide because of fragile geology which threats to the living things. Thus, to enhance the efficiency of vegetation recovery in landslide area can benefit the habitats of species. Typhoon Morakot induced landslides and vegetation recovery rate in Kao-Ping watershed can be quickly extracted and/or derived from the satellite images in this study. The biodiversity index established in the database of the watershed can then be applied to assess the treatment priority of landslides. The result shows that the highest landslide rate in Chi-Shan and Lao-Nong watersheds are Xiao-Lin and Ching-Shui Xi sub-watersheds respectively. For vegetation recovery rate, the downstream area is higher than upstream area. For treatment priority, the top 10 of sub-watersheds almost distribute in Lao-Nong watershed. It hopes that the result could provide the related authorities as the references of environmental restoration.台灣雖位處北回歸線，但因造山運動拱起4,000 公尺海拔落差，使台灣物種跨越熱帶、溫帶及寒帶，且四面環海及高溫多雨之島嶼氣候，孕育出許多台灣特有種生物，然台灣因高山多、平地少，在高人口密度下，居民為了生活不得不開發山坡地之原始森林，此舉壓縮了動、植物之生存空間，此外，台灣山高且地質破碎，夏季之暴雨或颱風易造成大規模之崩塌，除對當地居民造成威脅外，亦影響其他物種之生存環境，為此，如何加速崩塌地之植生復育，將有助於恢復各物種之棲地。本研究以莫拉克風災為事件，利用該事件前後期之衛星影像萃取集水區崩塌區位，另計算災後集水區植生復育良窳之熱點區位，最後以生物多樣性指數配合崩塌率及植生復育率評估集水區崩塌地治理之優選順序。研究結果顯示，旗山溪及荖濃溪集水區中崩塌率最高之子集水區分別為小林及清水溪；植生復育率則為下游高於上游區位；整體崩塌地治理優先順序中，得分最高之前10 處主要分布於荖濃溪集水區。期本研究之結果可作為相關生態保育單位於環境復育之參考