PREDATION HAZARD AND SEED REMOVAL BY SMALL MAMMALS - MICROHABITAT VERSUS PATCH SCALE EFFECTS

Predator avoidance may involve response strategies of prey species tha t are time and space specific. Many studies have shown that foraging i ndividuals avoid predators by altering microhabitat usage; alternative ly, sites may be selected according to larger-scale features of the ha bitat mosaic. We measured seed removal by two small mammal species (Pe romyscus leucopus, and Microtus pennsylvanicus) at 474 stations over a n experimentally created landscape of 12 patches. and under conditions of relatively high (full moon) and low (new moon) predatory hazard. O ur 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 pat ches than according to variation in structural microhabitats within pa tches. Specific responses included: under-utilization of patch edge ha bitats during full moon periods, and microhabitat effects that were on ly significant when considered in conjunction with larger-scale featur es of the landscape. Individuals residing on large patches altered use of microhabitats/habitats to a greater extent than those on smaller p atches. Studies just focusing on patterns of microhabitat use will mis s responses at the larger scales, and may underestimate the importance of predation to animal foraging behavior.