关键词: 小型啮齿动物, 种群系统, 复合因子理论, 食物可食用性, 捕食, 根田鼠, 种群动态

Abstract: This study determines the effects of nutrition，predation，and spacing behaviour interactions on the population demography of root voles，Microtus oeconomus，using a iactorial experiment design under enelosures in field．The effect patterns of food availability and predation on the population dynamics of the voles reported in this paper is the first part of the muhifaetorial hypothesis of population system regulation for small rodents.The specific hypothesis tested is that the availability of high-quality food and predation act independently and additively to limit the population densities Qf small rodents．
The results from four experimental treatments generally suppotted the hypothesis that food availability and predation have independent and additive effects on the vole populations．The predictions that the populations with supplemental food and no predation would reach the highest densities，those with no supplemental food and predator access (control)show the lowest densities，and those with single treatment have intermediate densities have been confirmed.A two—way AN0VA indicated that both food and predation treatments had significant effects on densities during 1— 20W K ．Prevention of predator accessing significantly affected the recruitments during 4— 20W K，but the effects of additional food on recruitments was somewhat less and only marginally signlficant．
The effects of both food and predation treatments on the densities and recruitments appeared to be additive (no significant interaction)and different in magnitude.Also as expected the patterns of recruitment and the instantaneous rate of population increase under four different treatments paralleled the observed density patterns．

Key words: Small rodents, Population system, Muhifaetorial hypothesis, Food availability, Predation, Root voles, Population dynamics