Value of Semi‐Open Corridors for Simultaneously Connecting Open and Wooded Habitats: a Case Study with Ground Beetles

Abstract

To counteract habitat fragmentation, the connectivity of a landscape should be enhanced. Corridors are thought to facilitate movement between disconnected patches of habitat, and linear strips of habitat connecting isolated patches are a popular type of corridor. On the other hand, the creation of new corridors can lead to fragmentation of the surrounding habitat. For example, heathland corridors connect patches of heathland and alternatively hedgerows connect patches of woodland. Nevertheless, these corridors themselves also break up previously connected patches of their surrounding habitat and in so doing fragment another type of habitat (heathland corridors fragment woodlands and woodland strips or hedgerows fragment heathlands). To overcome this challenge we propose the use of semi-open habitats (a mixture of heathland and woodland vegetation) as conservation corridors to enable dispersal of both stenotopic heathland and woodland species. We used two semi-open corridors with a mosaic of heathland and woody vegetation to investigate the efficiency of semi-open corridors for species dispersal and to assess whether these corridors might be a suitable approach for nature conservation. We conducted a mark-recapture study on three stenotopic flightless carabid beetles of heathlands and woodlands and took an inventory of all the carabid species in two semi-open corridors. Both methodological approaches showed simultaneous immigration of woodland and heathland species in the semi-open corridor. Detrended correspondence analysis showed a clear separation of the given habitats and affirmed that semi-open corridors are a good strategy for connecting woodlands and heathlands. The best means of creating and preserving semi-open corridors is probably through extensive grazing.

Genetic erosion in a stenotopic heathland ground beetle (Coleoptera: Carabidae): a matter of habitat size?

“…Two different types of ecological corridors have been shown to be effective for P. lepidus: open habitats with sparse vegetations, e.g. road side verges (Vermeulen 1994) and semi-open corridors (Eggers et al 2009) the latter of which have the advantage not to isolate woodland patches at the same time and which may therefore be a promising tool for connecting heathland patches.…”

Forty years of carabid beetle research in Europe – from taxonomy, biology, ecology and population studies to bioindication, habitat assessment and conservation

“…Dirt roads in forested landscapes may serve as dispersal corridors for open habitat species (Koivula 2002a), and roadsides overgrown with poplars have been suggested to serve as corridors for forest species with low dispersal power (Dymitryszyn et al 2003). Attempts to improve the connectivity of landscape elements by means of corridors may have contrasting effects on different carabid species according to their habitat requirements and, hence, new approaches regarding this matter are now under evaluation, such as semi-open corridors (Eggers et al 2010) and innovative, small scale forest harvesting techniques (Koivula et al 2002, see also Carabid conservation, protection and habitat management above).…”

Genetic erosion in habitat specialist shows need to protect large peat bogs

“…Also corridors intensively studied and discussed for ground beetles (e.g. Eggers et al 2010) as a surrogate for continuous habitats cannot be used due to the highly sensitive water table and nutrient conditions of peat bogs (Nick and Weber 2001;van Duinen et al 2003). The only possibility to preserve the populations of A. ericeti in the long run is the conservation of natural like peat bogs which should be large.…”