Document: TAY-3-65-5

The matrix matters: Effective isolation in fragmented landscapes.

RICKETTS, T.H.*

Stanford University, Stanford, CA 94305-5020 ¹

Abstract:
Habitat fragmentation threatens biodiversity by isolating populations in remnant patches, thereby increasing their extinction risk. The classical theories applied to such landscapes assume that the matrix surrounding the fragments is uniform; isolation is measured by distance alone. I conducted a mark-release-recapture study on 21 species of butterflies in 14 meadow patches and found that the type of surrounding matrix can significantly influence patch isolation. I used maximum likelihood techniques to estimate the relative resistances to butterfly movement of the two matrix types in the landscape: conifer and willow. For the majority of taxa studied, conifer was 2.5-11 times more resistant than willow. For the remaining taxa, resistance estimates were not significantly different, suggesting that responses to matrix differ even among closely related taxa. Modification of the matrix may provide opportunities for reducing the "effective isolation" of habitat patches and the extinction risk of populations in fragmented landscapes.

Keywords: fragmentation, matrix, landscape ecology, dispersal

This abstract is being presented at: 3:30 PM in session:
Oral Session #53: Terrestrial Invertebrate Ecology.