The Hemiptera of Two Sown Calcareous Grasslands. III. Comparisons with the Auchenorhyncha Faunas of Other Grasslands

Abstract

(1) The Auchenorhyncha faunas of two contrasting types of grasslands seeded on chalk at Royston, Herts., were compared with those from a range of semi-natural and agricultural grasslands. (2) Among intensively studied sites, the Royston fauna was most similar to that of Castor Hanglands, on oolitic limestone grassland, and less closely related to those of three established chalk grassland sites. The similarity of the Royston and Castor Hanglands faunas lay mainly in the predominance of Arthaldeus pascuellus at both sites. On the established chalk grassland sites other species, particularly Turrutus socialis, predominated. (3) The species richness of the Royston fauna was not markedly lower than the richness of established sites, but resident species were fewer. All sites had similar numbers of multiand bivoltine breeding species, but significantly fewer univoltine species bred at Royston. (4) Comparisons of annual totals of Auchenorhyncha recorded showed grouping strictly by site. (5) The Royston fauna was significantly richer than that of ryegrass leys on neutral soil, but not richer than the fauna of Park Grass, Rothamsted, though more individuals were recorded at Royston. (6) The Royston fauna was similar to the faunas of flood meadow grassland and 8-yearold seeded grassland on calcareous boulder clay in Cambridgeshire, particularly in the predominance of A. pascuellus. (7) An extensive survey of calcareous grassland sites for the Nature Conservation Review revealed few sites with faunas similar to that of Royston, mainly because A. pascuellus was not abundant on these sites. Sites surveyed more recently in Yorkshire and the East Midlands were similar to Royston, with A. pascuellus abundant on many of them. (8) The results are discussed in relation to the establishment of grasslands for wildlife conservation. Interactions with plant species composition, soil type, availability of nitrogen, and management are considered.