野生扬子鳄种群及栖息地现状研究

1999年7～8月及2000年8～9月，利用GPS、激光测距仪等，采用夜间灯光照射计数方法，对 有野生扬子鳄(Alligator sinensis)存在的安徽省宣州、泾县、广德、郎溪、南陵等5 县市的26个地点进行了调查，包括扬子鳄国家级自然保护区的13个指定保护点。结果发现： 目前野生扬子鳄主要生存在第一类栖息地（1999年50.7%、2000年40.0%），面积为17.38 hm²；其他两类栖息地的野生扬子鳄分布比率较小（各为1999年24.0%、2000年30.9%、1999 年25.3% 、2000年29.1%），面积分别为22.04hm²、19.03hm²。两年的平均生态密度分别为1.28条/hm²和1.79条/hm²，野生扬子鳄种群数量为145条。其种群已明显分为至少18个数 量不等且相互隔离的地方种群。建议恢复足够大的栖息地，并放饲养鳄于其中以重新 建立有效野生种群。

Study on the currentpopulation and habitat of the wild Chinese alligator (Alligator sinensis)

A survey of wild Chinese Alligator was conducted from July to August 1999 and from August to September 2000 by direct counting after dark (2000pm) using headlamps or a 12v portable spotlight. At each site visited, the authors mapped the ponds using laser rangefinder and compass, characterized the physical nature of the ponds and vegetation, and conducted interviews with local residents. The location of all sites was recorded using a hand-held GPS. There are 26 sites in 5 counties that were surveyed where wild Chinese Alligators still exist in Anhui province, including 13 designated conservation sites of the National Chinese Alligator Reserve. The current wild alligator populations mainly exist in the best type of habitat, which totals 17.4 ha with estimated populations of 50.7% in 1999 and 40.0% in 2000. This can be compared with the other two types of habitat, which total 22.0 ha and 19.0 ha, with their estimated population numbers of 24.0% in 1999 and 30.9% in 2000, and 25.3% in 1999 and 29.1% in 2000 respectively. The average ecological densities of the alligators in the two years were 1.3 ind./ha and 1.8 ind./ha, with an estimated population of 145 individuals. However, the population has been evidently divided into 18 isolated small local populations with different numbers of individuals. We suggest that habitat should be restored and captive-reared alligators should be reintroduced into the area to rebuild a viable population.