小型啮齿动物种群系统调节复合因子理论的野外实验研究：食物可利用性和捕食对根田鼠种群动态作用的分析

本研究在野外围栏条件下采用析因实验设计，测定营养、捕食及空间行为对根田鼠（Ｍｉ－ｃｒｏｔｕｓｏｅｃｏｎｏｍｕｓ）种群统计特征的影响。本文旨在检验下述特定假设：高质量食物可利用性和捕食对限制小型啮齿动物种群密度具有独立的和累加的效应。３年期间，４种野外实验处理６个重复的研究结果表明，附加食物并预防捕食者处理的种群具有最高密度；未附加食物及不预防捕食者处理（对照）的种群密度最低；而单一处理的种群，其密度居中。不同处理条件下，新生个体在种群的补充模式以及种群瞬时增长率的变化均与种群密度的变动相应一致。双因素ＡＮＯＶＡ的结果证明，附加高质量食物能明显地提高根田鼠的种群密度，而对种群补充量的作用则较弱，仅接近显著水平；预防捕食者不仅能显著地作用于种群密度，更能强烈地影响种群补充量。高质量食物和捕食者的作用具有累加的性质，两者的交互作用对种群密度和补充量均无显著影响。

FIELD EXPERIMENTAL STUDIES ON THE MULTIFA-CTORIAL HYPOTHESIS OF POPULATION SYSTEM REGULATION FOR SMALL RODENTS:AN ANALYSISOF EFFECTS OF FOOD AVAILABILITY AND PREDATION ON POPULATION DYNAMICS OF ROOT VOLE

This study determines the effects of nutrition , predation, and spacing behaviour in-teractions on the population demography of root voles,Microtus economus,using a facto-rial experiment design under enclosures in field. The effect patterns of food availabilityand predation on the population dynamics of the voles reported in this paper is the firstpart of the multifactorial hypothesis of population system regulation for small rodents.The specific hypothesis tested is that the availability of high-quality food and predationact independently and additively to limit the population densities of small rodents. The results from four experimental treatments generally supported the hypothesisthat food availability and predation have independent and additive effects on the volepopulations. The predictions that the populations with supplemental food and no preda-tion would reach the highest densities, those with no supplemental food and predator ac-cess(control)show the lowest densitie:,and those with single treatment have intermedi-ate densities have been confirmed. A two-way ANOVA indicated that both food andpredation treatments had significant effects on densities during 1-20WK. Prevention ofpredator accessing significantly affected the recruitments during 4-20WK , but the ef-fects of additional food on recruitments was somewhat less and only marginally signifi-cant. The effects of both food and predation treatments on the densities and recruitmentsappeared to be additive(no significant interaction)and different in magnitude. Also asexpected, the patterns of recruitment and the instantaneous rate of population increaseunder four different treatments paralleled the observed density patterns.