Landscape Versus Local Determinants of Butterfly Movement Behaviors.

Abstract

A thorough understanding of the mechanisms driving larger scale consequences of movement first requires an understanding of whether movement behaviors are related to local or landscape scale determinants. I studied the movement behaviors of four species of bottomland-dwelling butterflies in a natural setting to examine the determinants of movement behavior across different scales. Across spatial scales, I tested the relative importance and predictive value of three landscape attributes: topography, boundary contrast, and stream proximity, and two local habitat attributes: host plant cover and comprehensive vegetative structure. Across species, I tested the relative importance of organism size and habitat specificity to explain response variation. In general, butterfly responses to landscape features were stronger and more universal while responses to local features were weaker and more variable by species. Specifically, results from this study showed that topography does not influence movement behaviors but boundary contrast, stream proximity, and host plant abundance all contributed to movement patterns. Orientation to these features was not related to organism size, but did vary in accordance with habitat specificity. These results suggest that studies on dispersal in fragmented landscapes should consider the effects of that fragmentation on multiple scales. This consideration is particularly important in the management of rare species, when specific behaviors may ultimately affect the success of conservation efforts.