小型哺乳动物种群周期性波动的外因调节假说

The role of extrinsic factors in the regulation of periodic population dynamics in small mammals

对小型哺乳动物种群数量周期性波动的外因调节假说进行介绍 ,概述了食物假说、捕食假说和复合因子假说的主要内容和研究进展。在少数生存环境严酷的小型哺乳动物种群中 ,食物假说能解释它们的周期性数量波动现象 ,可能作为调节因子起作用 ,但难以说明低数量期的确切机制 ,对于大多数小型哺乳动物而言 ,它更可能作为限制因子。捕食假说解释了北欧芬诺斯坎底亚地区某些种群的周期性波动 ,尤其是捕食的间接效应已引起许多学者的关注 ,但也有不支持该假说的证据。对于复合因子假说 ,近年颇受学者重视 ,其中验证食物和捕食交互及累加作用的实验证据较多 ,有的研究还包括气候、种间竞争、空间或社会行为等因素。有关复合因子的实验研究 ,尽管工作是困难和艰巨的 ,花费也是巨大的 ,但所得结果却极有价值 。

This paper reviewed the new progress in the theory and hypothesis of population regulation in small mammals, focusing on the food hypothesis, predation hypothesis and multi-factorial hypothesis. The food hypothesis includes the role of food quantity, food quality and plant secondary compound in the regulation of population dynamics. In some species that lived in extreme environments, food might be a regulatory factor of the periodic population dynamics. However, food may very likely act as a limiting factor for most small mammals. The predation hypothesis has been considered to be a hopeful hypothesis for explaining the population cycles of some small mammals,with a particular emphasis on some voles and lemmings in the Scandinavian region. The predation hypothesis states that the direct and/or indirect effects of specialist predators on reproductive and physiological activities of northern arvicoline rodents are the cause of the periodic population fluctuation. There is also some evidence against the predation hypothesis. For the multi-factor hypothesis, some experimental manipulation demonstrated that the independent and additive effects of food availability and predation could cause the population cycles in some small mammals, sometimes combining with climate, interspecific competition, space and/or social behaviors. Though the multi-factor hypothesis has been considered as a most promising approach to study the population cycles of small mammals, due to logistic difficulties in the field and excessive expenditure, there is still not enough evidence to support this hypothesis. Additionally, it is difficult to identify the dominant factor(s) that could cause the periodic population fluctuations of small mammals. In spite of these difficulties, the multi-factor hypothesis should be an effective and reasonable way to solve the enigma. At last, we made some suggestions on how to advance the research on the population regulation of small mammals in China.