THE AUCHENORHYNCHA OF AN UNIMPROVED MOORLAND IN NORTHERN ENGLAND

1. Auchenorhyncha were sampled at seventy-four sites within an upland Calluna moorland/acidic grassland in Northumberland, England. Quantitative data on vegetation structure, plant species cover and soil conditions were also collected at each site. 2. Classification of the Auchenorhyncha species lists using two-way indicator species analysis identified three groups of assemblages ('communities') occurring at sites which appeared to differ in vegetation and soil conditions. 3. Canonical correspondence analysis revealed that four factors alone explained 21.1% of the between-site variation in Auchenorhyncha species lists. These were species richness of grasses, soil pH, and covers of woody plants and sedges. Inclusion of further variables did not significantly increase the variation explained. 4. The distributions of individual species of Auchenorhyncha, and hence the species composition and species richness of assemblages, were strongly influenced by the distributions of host plants. 5. Auchenorhyncha species richness was greatest at sites with the least acid soils and the highest covers and numbers of grass species. Sites dominated by sedges and woody plants supported the fewest species of Auchenorhyncha.