Effectiveness of Releasing Artificially-bred Chinese Giant Salamander (andrias Davidianus) Into the Wild in Zhangjiajie, Hunan

27 Mar Effectiveness of Releasing Artificially-bred Chinese Giant Salamander (andrias Davidianus) Into the Wild in Zhangjiajie, Hunan

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Abstract

大鲵(Andrias davidianus)是我国特有的两栖动物, 由于栖息地破坏和人类过度捕杀等, 种群数量急剧下降, 被列为我国II类保护野生动物。为探索大鲵人工放流的有效方法, 实现野生大鲵资源增殖, 作者对2002–2008年间 在湖南张家界大鲵国家级自然保护区内进行的大鲵人工放流活动与放流效果进行了评估, 并通过对放流点的隐蔽 物、水质及饵料生物等生境特点的分析, 探讨影响放流成败的因素。该保护区内共在9处大鲵原栖息地进行了11 次人工放流活动, 共放流各种规格大鲵995尾, 其中4次成功。成功放流的大鲵为1–4.5 kg的性成熟个体, 雌雄比在 1:1和1:1.5之间, 成功放流点均有良好的后期管理措施, 如建立保护站, 补充饵料等。虽然所选择的多数放流点生 境基本能满足大鲵生长和繁殖的要求, 但由于受水质、饵料或安全某一因素的制约, 野生大鲵资源增殖效果不明 显, 导致放流失败。因此我们认为依据野生大鲵繁殖的生境特征标准, 科学选择放流地点, 选择性成熟的大鲵在春 季放流, 并进行完善的后期跟踪保护, 可能是大鲵人工放流成功和实现资源增殖的有效途径。

English Abstract

Chinese giant salamander (Andrias davidianus) is a native amphibian to China. It was listed as
a Class II protected wildlife species under the state conservation law largely due to its sharply declined population size in the past two decades. Habitat destruction, habitat degradation and human over-exploitation
have been considered as the primary causes of the declination. Designed to boost the wild population, a captive breeding program has been successfully established and artificially bred individuals have been released
into the wild for many times in the Hunan Zhangjiajie Giant Salamander National Nature Reserve between 2002 and 2008. In 2007 and 2008, we examined these released salamanders to evaluate the effectiveness of the release. We also investigated covert, water quality and food organisms of the releasing
sites to explore factors that may determine the success of release. A total of 995 different sized salamanders
were identified as 11 cohorts at nine releasing sites. However, only four cohorts were identified as successful
in terms of wild population size increase. In all successful sites, released salamanders were mature, weighing
1–4.5 kg, and sex ratios were between 1:1 and 1:1.5. Moreover, some protection measures were taken including food supplementation in these sites. Most releasing sites appeared to satisfy the demands for growth
and reproduction of the salamander, however, most releases failed to boost the wild populations likely due to
the limitation of the factors such as water quality, food organisms and safety. In conclusion, habitat traits of
releasing sites and subsequent management measures, as well as individual size of salamanders were the major factors affecting the releasing effectiveness. In view of the habit of the salamanders, it is better to select
mature salamanders for release in spring.