Spatial dynamics of ground beetle (Coleoptera: Carabidae) assemblage in a forest and open habitat mosaic landscape

• Main Author: Bertoncelj, Irena
• Published: University of East Anglia 2009
• Subjects: 595.76
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.569296

This thesis explores the relative importance of within-patch habitat quality, the temporal persistence and spatial connectivity of habitat patches, for heathland ground beetle assemblages in a forested and open habitat landscape mosaic of Breckland, Eastern England. Comparison of the carabid fauna of two distinct landscape elements: remnants of once extensive lowland heathland and the pine plantations of Thetford Forest managed by rotational clear-felling, showed the high value of the forest landscape for carabid species restricted to grassland, heathland and sandy habitats (GHS). Within the forest landscape, temporal changes in carabid community in planted stands are determined by management and succession, with conditions suitable for GHS species persisting for just seven years after replanting. For persistence of GHS species within Thetford Forest permanent open space, representing approximately ten percent of the area, is essential. Habitat quality, particularly greater cover of bare sand, lower sward and shallow soil litter, were more important predictors of patch suitability for GHS species than patch size. Suitability of linear trackway elements within the plantation was determined by the surrounding matrix, with high GHS species richness in trackways surrounded by younger plantations (<20 years) and very few GHS in those surrounded by older plantations. Behaviour of the model arenicolous species Harpalus rufipalpis differed between these two types of trackways, with greater levels of activity and more leakage in poor quality trackways surrounded by older trees; thus only a subset of trackway elements will serve as corridors for conduit. Despite the interrupted nature of this network, colonisation of newly created clear-fells by GHS species was not affected by their isolation, at least at the current scale of management. Almost all GHS species recorded in permanent open habitats were shown to successfully colonise ephemeral open patches: colonists did not represent a subset of GHS species and were not filtered by dispersal ability.