Are small-scale landscape features important factors for field studies of small mammal dispersal sinks?

Interest in the influence of landscape features on animal movement has been widespread; however, few field studies of the emigration of small mammals from patches of habitat directly consider the effects of the small-scale landscape features. The simulation models of Stamps et al. (1987a, b) and Buechner (1987a, b) suggest that the size of a dispersal sink relative to the size of the source patch, the average distance traveled by dispersers in the sink, the ease with which dispersers cross the edge between the sink and a source patch, and source patch perimeter: area ratio may all be important influences on emigration rates. A review of field studies of small mammal dispersal into sinks suggests that in a substantial fraction of such studies the values of these factors fall within the ranges that the simulation models indicate have the greatest potential effect on emigration rates. New field studies of dispersal sinks that include a consideration of these factors are necessary in order to evaluate the magnitude of the impact of these factors on natural populations.