Corridor function of a road verge for dispersal of stenotopic heathland ground beetles carabidae

Abstract

To reduce the effects of habitat isolation dispersal corridors between habitat fragments are often proposed. In this study the corridor function of a poor sandy roadside verge, adjacent to an open area of drift sand, was investigated for ground-dwelling arthropods. Three species of carabid beetles characteristic of this habitat, Pterostichus lepidus, Harpalus servus and Cymindis macularis, were marked and released at four different sites. Exchange of individuals of these species was recorded between the road verge and the open sandy area, and dispersal along the road verge was established. The rate of movement along the road verge was low compared to that in the open area. Sites with trees and narrow sites at the road verge had a barrier effect. Reproduction was recorded for two species at broad areas in the road verge. Under certain conditions (re) colonization of habitat areas by dispersal along a long, ribbon-like habitat might occur. For each species the specific features of such a corridor is discussed.