台灣狐蝠的野外族群現況

On the Current Status of Field Population of Formosan Fruit Bat）Pteropus dasymallus formosus%

台灣狐蝠（Pteropus dasymallus formosus）為臺灣地區唯一屬於大翼手亞目的食珎蝠類，主要分布於綠島，民國78年起依野生動物保育法已列為瀕臨絕種動物。惟自保護以來，有關狐蝠的野外族群生存現狀仍甚為不詳。本研究乃於綠島地區進行全島性的普查，探究台灣狐蝠的族群量與分布情形，並針對當地28位成年人及1位獵人進行訪查，以了解本種瀕危之原因。自民國82年12月至85年6月止二年半的野外調查，在共計8條的勘察路線中，於過去狐蝠的四個棲所處並未發現任何台灣狐蝠的族群。20年前綠島的狐蝠族群數量可能超過2000隻，而過去最主要棲所處－－龜灣的族群卻不復存在，但在整個調查期間，此處除了有2次單隻個體來自他人的觀察記錄外，研究者曾於傍晚時發現1隻疑似台灣狐蝠飛翔於天際。訪查結果顯示，有39%的人認為狐蝠已絕種，有61%的人認為狐蝠的族群量已甚為稀少，僅有5位明確回答出見過狐蝠的時間，約1年半前至15年前。獵人過去捕捉台灣狐蝠是採用能獲得較多個體的鳥網方式，咸信過度捕捉是造成本種稀少或近絕種的主要原因。另外，林相改變使狐蝠的食物來源樹種（榕樹屬為主）減少，亦影響狐蝠的生存狀況。持續追蹤綠島地區狐蝠的生存狀況及規劃本種的復育工作將是未來台灣狐蝠保育的主要工作。 1Laboratory of Wildlife Ecology, Department of Biology, Tunghai University, Taichung, Taiwan, 407 2Department of Wildlife Conservation, National Pingtung University of Science and Technology, Neipu, Pingtung, Taiwan, 912 The Formosan fruit bat (Pteropus dasymallus formosus) is the only known species of Megachiroptera in Taiwan. It mainly inhabits on Green Island southeast of Taiwan. The fruit bat was listed as an endangered species by the Wildlife Conservation Law (1989) but its actual populations was unknown. Interviews with 28 local residents and one hunter were made to document the causes of population decline. From December 1993 to June 1996, eight surveys were made, and failed to find any colony of the fruit bat at the four major roosting areas. In the early 1960s_ there might be over 2,000 bats on Green Island. Since then, the largest roosting area at Guei-Uan, has completely collapsed. Aside from two possible sightings by other people at Guei-Uan, this study has an unverified sighting of a fruit bat flying in the sky at dusk. According to the interview results, 39% of the interviewees believed that the fruit bat was extincted, and 61% thought the population had declined dramatically. Five interviewees reported seeing the fruit bat in recent years. The decline of the fruit bat was due to overhunting suggested by one hunter who used mist nets. Creation of plantation forests and the destruction of native forest (Figus sp.) accelerated the decline of the fruit bat on Green Island. Monitoring and restoration of the fruit bat population on Green Island is essential for its conservation.