BUTTERFLY MOVEMENTS AMONG ISOLATED PRAIRIE PATCHES: HABITAT EDGE, ISOLATION, AND FOREST-MATRIX EFFECTS

by Stasek, David Jon

The spatial structure of a population is often determined solely by the frequency of interpatch movements. Landscape structural features and the behavioral response of organisms to these features affect animal movements among suitable habitat patches, but these factors have not been applied to spatial population studies. I recorded the movements, abundance, and behavioral response to the habitat edge of two species of butterflies, the great-spangled fritillary (Speyeria cybele) and the pearl crescent (Phyciodes tharos), among remnant prairie patches in south-central Ohio to determine the spatial structure of the populations and the mechanistic basis of movements among patches. The great-spangled fritillary exhibited characteristics of a patchy population because of the relatively high number of interpatch movements and its greater abundance at the patch edge. The pearl crescent moved infrequently among patches and was isolated within patches by the patch edge and all forest-matrix types, suggesting a classic metapopulation structure.