旅游干扰的水质模拟对繁殖前期中国大鲵夜间活动节律的影响

动物的日活动节律是它们对各种环境条件昼夜变化的综合适应。研究旅游干扰对繁殖前期中国大鲵(Andrias davidianus)的夜间活动节律影响,有助于探明旅游干扰是否以及如何影响大鲵繁殖行为的机理。前期研究发现旅游干扰程度与水中溶解氧(Dissolved Oxygen,DO)含量显著负相关。在大鲵繁殖前期,通过控制大鲵生态繁育池水中的进水量(主要影响DO含量)来模拟重度与轻度旅游干扰下大鲵水环境,通过监测大鲵夜间出洞与进洞时间、水温(Water Temperature,WT)、DO和大肠菌群的动态变化,比较不同旅游干扰强度下大鲵夜间活动节律的差异,以明确旅游干扰导致的水质变化对大鲵夜间活动节律的影响。结果表明,雌/雄鲵出洞时间在模拟重度旅游干扰水质下显著晚于轻度水质中,雌鲵分别为19:10±0:22与18:53±0:24,雄鲵分别在18:29±0:20与18:13±0:18。重度干扰导致水质变化分别推迟了雌/雄大鲵出洞时间约17 min与16 min。但是,雌雄大鲵进洞时间在模拟重度与轻度旅游干扰水质下,差异不显著,雌鲵分别为24:10±0:13与24:18±0:17,雄鲵分别为6:44±0:23与6:40±0:29。此外,该研究还发现,雌/雄鲵出洞时间与三种因子(WT、DO与大肠菌群)显著相关,然而,雌/雄鲵进洞时间与以上3因子不相关,可能主要由其生物钟决定。重度旅游干扰导致的水质变化对大鲵繁殖前期活动节律影响小,仅对出洞时间有一定影响。

Effects of the water quality simulation of tourism disturbance on nocturnal activity rhythm of Chinese giant salamander (Andrias davidianus) during its pre-reproduction period

The diurnal rhythm of an animal indicates a comprehensive adaptation to various circumstances. Study on the relationship of tourism disturbance and the nocturnal rhythm of Chinese giant salamanders (CGS, Andrias davidianus) could shed lights on whether and how tourism disturbances affect its breeding behaviors. Previous studies have shown a significantly negative correlation between the intensity of tourism disturbance and the content of dissolved oxygen (DO) in water. In this study, we simulated the water environment as high and low tourism disturbances by controlling the influent volume (mainly affecting DO content) in the ecological breeding ponds of CGS. By monitoring the dens exit and entry time of CGS, measuring the dynamic changes of water temperature (WT), DO, and the contents of coliforms, we compared the changes of nocturnal rhythm under different factors of water quality, and discussed the patterns of nocturnal rhythm in response to different tourism disturbances. The results showed that the dens exit time of both female and male CGS in the simulated high tourism disturbance waters were significantly later than that in the low tourist disturbance waters. Under these two water conditions, the dens exit time for females were 19:10±0:22 and 18:53±0:24, and for males were 18:29±0:20 and 18:13±0:18, respectively. The time that female and male CGS in the high disturbance water exited from the dens were delayed for about 17 min and 16 min, respectively. However, there were no significant differences between the dens entry time of CGS (including both males and females) under two simulated tourism disturbance waters. Under these two water conditions, the dens entry time for females were 24:10±0:13 and 24:18±0:17, and for males were 6:44±0:23 and 6.40±0:29, respectively. In addition, we also found that the dens exit time of CGS had significant correlations with three factors (WT, DO and coliforms). However, there were no significant correlations between the dens entry time of CGS and WT, DO and coliforms, which may indicate that the dens entry time was mainly determined by the circadian clock. In summary, changes in water quality under high tourism disturbance had a moderate impact on the nocturnal rhythm of CGS during the pre-reproduction period, which was mainly reflected from the dens exit time.