PATCH ISOLATION, CORRIDOR EFFECTS, AND COLONIZATION BY A RESIDENT SPARROW IN A MANAGED PINE WOODLAND

The isolation of habitat patches is often cited as having a major impa ct on the dynamics of small populations occupying patches in a complex landscape. Few studies, however, have provided field data demonstrati ng that isolation has an identifiable effect on specific populations i ndependent of other factors such as local habitat quality or that land scape factors such as corridors can alleviate such effects. We conduct ed field surveys of Bachman's Sparrow (Aimophila aestivalis) populatio ns in regions, which we call linear landscapes where suitable habitat patches were isolated to varying degrees from potential sources of dis persing birds. In these linear landscapes isolated patches of habitat were less likely to be colonized than were nonisolated patches. We als o found that corridor configuration; of habitat patches improved the a bility of sparrows to find and settle in newly created patches. These results suggest that for species that do not disperse easily through i nhospitable landscapes, habitat occupancy at a regional scale can be e nhanced by careful landscape design and planning.