Grouse moor management: habitat and conservation implications for invertebrates in southern Scotland

The distribution of ground beetle, rove beetle, spider and plant bug species assemblages, and the occurrence of other beetle species, was investigated in a five-year survey of a grouse moor in the Scottish borders, some of which was managed by burning, cutting and herbicide application. Multivariate analyses were used to assess the relationship between assemblage distribution and a number of environmental variables. The management of dry Calluna moor had a positive effect on the habitat diversity for ground beetles and plant bugs but had little effect on rove beetles and spiders. A total of 39 nationally rare and scarce species (38 beetle, 1 plant bug) was recorded in the survey. The most important habitat present was on streamside sites, especially sediment. A number of these rarer species were restricted to sites managed by burning and cutting but other species were only found on unmanaged wet Calluna moor. Molinia-dominated moor was generally of poorer quality than Calluna sites, with fewer rare and scarce species and lower site rarity values based on the ground beetle species recorded. The highest median site rarity scores were for dry, open, managed Calluna sites. In order to maximise both habitat diversity and the incidence of rare and scarce species on grouse moor, a mosaic of both managed and undisturbed patches differing in soil characteristics, plant composition and vegetation structure appears to be required.