水温对大鲵野外放流的影响初探

Study on the Impact of Water Temperature on the Artificial Releasing of Chinese Giant Salamander(Andrias davidanus)

大鲵是我国特有的两栖纲有尾目隐鳃鲵科动物。然而由于生境破坏、环境污染和人为捕杀等原因,该物种数量锐减,被列为国家Ⅱ类重点保护野生动物。为恢复大鲵野生资源数量,进一步评估水温、水质、饵料生物和两岸植被类型等生境因子对大鲵人工放流结果的影响,作者于2013年4月在秦岭山脉南麓(宁陕东河)、北麓(周至黑河)选择放流点分别人工放流16尾和15尾健康大鲵个体。利用PIT芯片进行标记追踪,实时监测水温变化,定期采集周边生境因子数据,一年后南、北麓回捕标记个体8尾和0尾,回捕率分别为50%和0。结果显示,南麓放流点日平均水温显著高于北麓放流点(p<0.01),最高温度较北麓放流点高3.85℃,最低温度较北麓放流点高4.26℃,且南麓放流点水温日均温差变化较小。我们认为水温是影响放流成功与否的重要因子,因此,依据野生大鲵的生境特征标准,选择水温更加适宜的放流点,可能是大鲵人工放流成功和实现野生资源增殖的有效途径。

Chinese giant salamander（Andrias davidanus） is a specific amphibian belonging to the general accounts of Amphibia Gymnophiona and Urodela.However,due to habitat destruction,environmental pollution,and over-exploitations,the species has suffered a sharply declined population size and was listed as a Class H protected wildlife species under the national conservation laws.In order to increase the wild population and evaluate the effect of the water temperature,water quality,food organisms and the vegetation along the releasing sites on the result of Giant salamander artificial releasing,the authors have been released 16 and 15 healthy artificial stocking individuals into the Donghe River（south slope of the Qinling Mountains） and Heihe River（north slope of the Qinling Mountains） in April,2013,respectively.Tracking by PIT chip tags,monitoring the changes of the water temperature and collecting the other environmental factors for one year,we examined recapture individuals were 8 and 0,respectively,and the recapture rate was 50%and 0,respectively.The results showed that the day average water temperature at Donghe River was significantly higher than Heihe River（p〈0.01）.The maximum and minimum water temperature at Donghe River was 3.85℃ and 4.26℃,and water temperature variation at Donghe River was smaller.In conclusion,water temperature was the major factor which affected the releasing effectiveness.Therefore,we believed that based on standard wild giant salamander habitat characteristics,choosing a more suitable temperature releasing sites may be an effective way to achieve success and proliferation of wildlife resources.