Bowers Michael A, Dooley James L
Department of Environmental Sciences and Blandy Experimental Farm, University of Virginia, Clark Hall, 22903, Charlottesville, VA, USA.
Oecologia. 1993 May;94(2):247-254. doi: 10.1007/BF00341324.
Predator avoidance may involve response strategies of prey species that are time and space specific. Many studies have shown that foraging individuals avoid predators by altering microhabitat usage; alternatively, sites may be selected according to larger-scale features of the habitat mosaic. We measured seed removal by two small mammal species (Peromyscus leucopus, and Microtus pennsylvanicus) at 474 stations over an experimentally created landscape of 12 patches, and under conditions of relatively high (full moon) and low (new moon) predatory hazard. Our objective was to determine whether predator avoidance involved the selection of small-, medium-, or large-scale features of the landscape (i.e., at the scale of microhabitats, habitats, or habitat patches). We found rates of seed removal to vary more with features of whole patches than according to variation in structural microhabitats within patches. Specific responses included: under-utilization of patch edge habitats during full moon periods, and microhabitat effects that were only significant when considered in conjunction with larger-scale features of the landscape. Individuals residing on large patches altered use of microhabitats/habitats to a greater extent than those on smaller patches. Studies just focusing on patterns of microhabitat use will miss responses at the larger scales, and may underestimate the importance of predation to animal foraging behavior.
躲避捕食者可能涉及猎物物种在时间和空间上具有特异性的反应策略。许多研究表明，觅食个体通过改变微生境的使用来躲避捕食者；或者，栖息地可能会根据栖息地镶嵌体的更大尺度特征来选择。我们在一个由12个斑块组成的实验性景观中的474个站点，以及在相对高（满月）和低（新月）捕食风险的条件下，测量了两种小型哺乳动物（白足鼠和宾夕法尼亚田鼠）的种子移除情况。我们的目标是确定躲避捕食者是否涉及对景观中小尺度、中尺度或大尺度特征的选择（即微生境、栖息地或栖息地斑块的尺度）。我们发现，种子移除率随整个斑块的特征变化比斑块内结构微生境的变化更大。具体反应包括：在满月期间斑块边缘栖息地利用不足，以及微生境效应只有在与景观的更大尺度特征结合考虑时才显著。生活在大斑块上的个体比生活在小斑块上的个体更大程度地改变了微生境/栖息地的使用。仅关注微生境使用模式的研究将忽略更大尺度上的反应，并且可能低估捕食对动物觅食行为的重要性。
