Vegetation preference at multiple scales: Do small scale movement decisions shape landscape level distribution of butterflies

Background/Question/Methods   A central question in landscape ecology is how organisms are distributed in fragmented landscapes. To answer this, we need to determine the relative abundance of organisms across different vegetation types and understand how they behave at vegetation borders. While it is likely that large scale patterns of animal distribution and movement are determined by mechanisms acting at local scales; the degree to which behavior at vegetation borders scales up to overall vegetation preference is unknown. Butterflies are ideal organisms to answer questions related to movement behavior, as their behavioral decisions are often less complicated than vertebrates. Further, the majority of species move distances that are amenable to landscape level studies of fragmentation. This study focuses on a guild of fruit feeding nymphalid butterflies and how they react to fragmentation in a post agricultural landscape, with emphasis on the behavior and distribution of the Hackberry Emperor Asterocampa celtis and the Question Mark Polygonia interrogationis. This work was conducted at the University of Virginia's Blandy Experimental Farm. Using a combination of observations at habitat edges and large scale trapping across different vegetation types, we measured fruit feeding nymphalid vegetation preference at habitat-matrix borders and how this preference scaled up to landscape level butterfly distribution.

Results/Conclusions   A formal inventory of fruit feeding nymphalid butterflies allowed us to confirm a pattern that had not been previously quantified; that fruit feeding Nymphalids are closely tied to late successional vegetation. By comparing these inventory data to edge circle data designed to measure vegetation preference, we determined that vegetation preference at the 5-10 meter scale was representative of vegetation preference at the landscape level. This suggests that these small scale decisions being made at vegetation borders likely play a key role in determining the distribution of these species in a landscape.