Sundell Janne, Ylönen Hannu
Metapopulation Research Group, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki, FinlandKonnevesi Research Station, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland.
Integr Zool. 2008 Mar;3(1):51-63. doi: 10.1111/j.1749-4877.2008.00077.x.
Dissimilar vulnerabilities of different prey types and preferences of predators are factors likely to contribute to community dynamics. This may happen via differential individual properties of prey animals (e.g. vigilance, escape) or via habitat effects making hunting by a predator easier and more rewarding in some habitats, or both. Furthermore, community dynamics may be influenced by predator mediated apparent competition, in which an increase in one prey type has negative effects on another prey type indirectly via the shared predator. We summarize the current knowledge from the field in a model predator-prey system consisting of sympatric boreal vole species and their common specialist predator and review field studies using predator manipulation and studies on the responses of individuals in the laboratory and in outdoor enclosures. The vole species studied represent different prey types that are thought to have different vulnerabilities. Our observations on the main resident specialist predator, the least weasel (Mustela nivalis nivalis L.), show that it hunts according to prey availability and suitability of the hunting habitat. Prey voles respond to the presence of the predator behaviorally in various ways to avoid predation. We conclude that even if the least weasel is a specialized predator of small rodents it acts like a generalist predator within the small rodent guild and may facilitate the coexistence of prey species via predator switching. This may lead to interspecific synchrony between prey populations, which has often been observed. We suggest that the processes determining the community impact of predator-prey interactions are driven by the behavioral arms race between the predator and the prey, together with the habitat-dependent density of prey and net gain for the predator.
不同猎物类型的不同脆弱性以及捕食者的偏好是可能影响群落动态的因素。这可能通过猎物动物的个体差异属性（如警觉性、逃跑能力）发生，或者通过栖息地效应，使捕食者在某些栖息地的捕猎更容易且更有收获，或者两者皆有。此外，群落动态可能受到捕食者介导的表观竞争的影响，即一种猎物类型的增加会通过共享的捕食者间接对另一种猎物类型产生负面影响。我们在一个由同域分布的北方田鼠物种及其常见的专一捕食者组成的捕食者 - 猎物模型系统中总结了该领域的现有知识，并回顾了使用捕食者操控的野外研究以及在实验室和室外围栏中对个体反应的研究。所研究的田鼠物种代表了被认为具有不同脆弱性的不同猎物类型。我们对主要的常驻专一捕食者伶鼬（Mustela nivalis nivalis L.）的观察表明，它根据猎物的可获得性和捕猎栖息地的适宜性进行捕猎。猎物田鼠会以各种行为方式对捕食者的存在做出反应以避免被捕食。我们得出结论，即使伶鼬是小型啮齿动物的专一捕食者，但在小型啮齿动物群落中它的行为类似于泛化捕食者，并且可能通过捕食者转换促进猎物物种的共存。这可能导致猎物种群之间的种间同步，这是经常被观察到的。我们认为，决定捕食者 - 猎物相互作用对群落影响的过程是由捕食者和猎物之间的行为军备竞赛，以及猎物的栖息地依赖密度和捕食者的净收益驱动的。
