年龄、性别及季节因素对千岛湖岛屿社鼠最大活动距离的影响

2009年7-11月及2010年3-11月,在千岛湖2个岛屿上进行社鼠(Niviventer confucianus)的标志重捕,根据春、夏、秋3个季节将重捕4次以上的社鼠进行最大活动距离计算,分析年龄、性别及季节对岛屿社鼠最大活动距离的影响.结果显示,岛屿间无显著差异；将2岛数据合并后,幼年、亚成年、成年及老年4个年龄组社鼠最大活动距离之间差异极显著；雄性社鼠最大活动距离极显著地大于雌性,4个年龄组雌雄之间的最大活动距离均表现为雄性＞雌性,但仅成年组雌雄之间存在极显著差异；春、夏、秋3个季节之间的最大活动距离差异极显著,而仅亚成年组在3个季节之间存在极显著差异,雌性和雄性社鼠均表现春季＜夏季＜秋季,但只在春季表现出雌雄个体之间差异极显著,与以往巢区研究结果不一致,可能反映了岛屿环境下社鼠巢区活动的特殊性.显示岛屿隔离环境对小型哺乳动物巢区活动有影响,但这种岛屿效应仍有待深入研究.

Effects of age, sex and season on the maximum movement distance of Niviventer confucianus in Thousand Island Lake

Chinese white-bellied rats, Niviventer confucianus, were mark-recaptured from July to November, 2009 and from March to November, 2010 on two islands of the Thousand Island Lake region. The maximum movement distances of Chinese white-bellied rats that were recaptured 4 or more times were calculated in spring, summer and autumn by Biotas 2.0. Then we used independent sample T test, one-way ANOVA or Mann-Whitney U test to analyze the effects of age, sex and season on the maximum movement distance. We aim to explore movement and home range of Chinese white-bellied rats in isolated island environment, and to predict its behavioral responses to isolated island environment. The results showed that there was no significant difference in the maximum movement distance between two islands, and the data of the two islands could be pooled. There were highly significant differences in the maximum movement distance among four different age groups. The maximum movement distance of males was significantly longer than females in adults, but did not differ between the sexes in any other age groups. The maximum movement distance differed significantly among spring, summer and autumn in sub-adults, but not in other age groups. The maximum movement distance of both males and females was longest in autumn and shortest in spring. Our results indicate that the maximum movement distance is positively correlated with the age of Chinese white-bellied rats, and is significantly longer in males than females. Our results were inconsistent with some of the previous studies on home range size in rats. This inconsistency likely reflects the restriction of resources in isolated island environment and specificity of behavior in Chinese white-bellied rats. This study preliminarily displays the effects of island isolation on small mammals, and more studies are needed to examine the island effects in the future.