Submitted to: Landscape Ecology Symposium
Publication Type: Abstract Only
Publication Acceptance Date: March 26, 1996
Publication Date: N/A
Technical Abstract: Borders separating landscape patches filter the movement of organisms across them. Hard edges prevent organisms from moving across them, while soft edges allow organisms to move freely across them. Carabids are polyphagous predators of wheat crop pests and often move into wheat fields from contiguous grasslands. Carabids were captured at four different locations in pitfall traps positioned in grasslands, wheat fields, and along the grassland-wheat field borders. The traps were established in October 1993 and checked weekly through May 1994. Of 51 carabid species collected, the most abundant were Agonum punctiforme, Bembidion castor, B. nigripes, and Pterostichus chalcites. Some species of carabids moved without hindrance across the borders, while others were impeded by the borders. Carabids that moved freely across borders were classified as soft edge species. Carabids that were impeded by borders were classified as hard edge species. Carabid activity densities were higher near borders tha in the interior of wheat fields, suggesting that grasslands may serve as a reservoir for habitat generalist species to colonize wheat fields after planting.