Movement and spatial organization of small mammals following vertebrate predator exclusion.

Predation directly changes the demographics of prey, generally through a numerical decrease. An indirect effect of predators is alteration of movements and spatial patterns of prey. The relationship between these direct and indirect effects can be tested by excluding predators. Home range size of white-footed mice (Peromyscus leucopus) decreased and home range overlaps increased in the absence of predators. Home range size and overlaps of meadow voles (Microtus pennsylvanicus) did not change despite an increase in vole density. P. leucopus had significantly lower interspecific home range overlaps with M. pennsylvanicus than intraspecific overlaps. The changes in P. leucopus spatial behavior may be an indirect effect of predator exclusion resulting from the increase in M. pennsylvanicus densities.