Role of Predation and Plant-Small Mammal Interactions in theChilean Mediterranean Scrub Zone.

该项目的目的是研究生物相互作用在智利小型哺乳动物组合中的作用。捕食、植物与小型哺乳动物的相互作用和种间竞争正在被研究，实验中排除了捕食者，以及最丰富的小型食草哺乳动物——大鼠。每月将对小型哺乳动物的数量进行普查，并通过粪便/颗粒收集和分析、嗅觉线和呼叫回放来监测捕食者的饮食和活动。每隔4个月进行点截采样，全年生长期每月采样；每4个月采集一次土壤样本，追踪种子密度。自1989年5月实验开始以来，存在类似的初始条件，植物物种覆盖、组成或种子密度几乎没有变化。在春季（1989年9 - 11月），捕食者排除样地的degus数量较多，全年存活时间和存活率均显著较高。其他小型哺乳动物对捕食者/degu排斥的反应不一。由于小型哺乳动物群落和植物群落的变化可能是长期的，因此要求继续提供三年的支持。这个大规模的项目代表了温带新热带脊椎动物群落中生物相互作用的第一个长期研究。

The objective of this project are to examine the role of biotic interactions in a Chilean small mammal assemblage. Predation, plant-small mammal interactions, and interspecific competition are being studied with experimental exclusions of predators, and the most abundant small mammal herbivore, the degu rat, from fenced exclosures. Small mammal populations will be censused monthly, and predator diets and activity monitored by scat/pellet collections and analysis, and olfactory lines and call playbacks. Plant community changes are followed with point intercept sampling each 4 months, and monthly sampling during the annual growing season; soil samples every 4 months track seed densities. Similar initial conditions were present, and few changes in plant species cover, composition or seed densities have occurred since experiment initiation in May 1989. Numbers of degus in predator exclusion plots were higher during spring (September-November 1989): survival times and rates were significantly higher throughout the year. Responses of other small mammal species to predator/degu exclusions have been mixed. Continued support is requested for three years since changes in the small mammal assemblage and plant community are likely to be long-term. This large scale project represents the first long- term study of biotic interactions in a temperate Neotropical vertebrate assemblage.