关键词: 小型啮齿动物, 种群系统, 复合因子理论, 食物可利用性, 捕食, 根田鼠, 空间行为

Abstract: The effect pattern of food and predation on spacing behaviour of root voles(Microtus oeconomus)reported in this paper is one part of the multifactorial hypothesis of population regulation for small rodents．The two specific hypotheses tested are:1)greater availability of high quality food reduces aggression and movement of root voles;and 2) exposure to predators reduces movement of root voles．
The results showed that food availability could act directly or indirectly on spacing behaviour of root voles．Mean densities increased and mean home range size decreased in populations with supplemental food.Food acted indirectly on home range size via the effect of food on population density. Compared with other treatments,voles with supplemental food were less aggressive toward one another and showed fewer long movements between trapping sessions．Exposure to predation did not affact aggression among voles，but it appeared to reduce long movements between trapping sessions．This reduced long movement was probably a direct behavioural response of voles to the presence of predators．We conclude that factors extrinsic to the vole populations can influence behaviour directly or indirectly．Such interactions should be consideredcarefully when explaining the population dynamics of voles．

Key words: Small rodents, Population system, Multifactorial hypothsis, Food availability, Predation, Root voles, Spacing behaviour