Conservation potential for heathland carabid beetle fauna of linear trackways within a plantation forest

Exploring conservation and connectivity potential of landscape linkages implies studies on the level of population and community structure. We examined carabid beetle communities within a network of open linear trackways embedded in a plantation forest, in a region where conservation interest focuses on heathland associated species. The relative importance of environmental characteristics such as width, orientation, age of surrounding plantations and vegetation height on species associated with grassland, heathland and sandy habitats (GHS species) was explored in 36 trackway elements. A total of 3554 individuals were collected of which 1465 were GHS specialists. Linear trackways supported important carabid beetle diversity including 17 GHS species of which six are nationally scarce within the UK. The age of adjacent plantations was the most important factor determining community composition of carabids with GHS species favouring trackways surrounded by younger plantations. For predicting number and abundance of GHS species within a subset of trackways surrounded by younger plantations, models incorporating sward height in verges showed the strongest relationships. But results were statistically significant only for predicting abundance of the dominant GHS species Harpalus rufipalpis, which favoured wider trackways with lower vegetation and greater cover of bare sand. Current conservation management using forage harvesting of trackways does not improve habitat quality for GHS carabids. Seemingly continuous network of linear linkages is interrupted by sections of less suitable habitat surrounded by older plantations. Conservation potential could be enhanced by widening of trackways and management by physical disturbance of soil and vegetation.