Moorland Beetle Communities on Limestone `Habitat Islands'. I. Isolation, Invasion and Local Species Diversity in Carabids and Staphylinids

• Published in: The Journal of animal ecology 1989-10, Vol.58 (3), p.1077-1098
• Main Author: Bauer, Lucy J.
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Beetles; Biological and medical sciences; Biological taxonomies; Carabidae; Coleoptera; Fauna; Fundamental and applied biological sciences. Psychology; Habitats; Limestone grasslands; Moorlands; Outcrops; Peat; Species diversity; Staphylinidae; Synecology; Taxa; Terrestrial ecosystems
• ISSN: 0021-8790; 1365-2656
• DOI: 10.2307/5143

(1) Carabid and staphylinid faunas of isolated limestone outcrops and adjacent peat were studied using pitfall and window traps on two areas of Cumbrian moorland. (2) Multivariate analysis of data from the Moor House National Nature Reserve revealed marked variation in faunal composition between habitats, with species richness and diversity being significantly higher on limestone grassland than on blanket peat. (3) Similarity levels between faunas from the limestone and peat habitats were negatively correlated with the size of the limestone outcrop. (4) Species were categorized by preferred habitat type, as Settled (Limestone, Peat, Widespread and Vagrant) and Nomadic. (5) Data from the Tailbridge Hill transect across a limestone grassland-blanket peat interface indicated an intermingling of Limestone and Peat species at the habitat boundary. Dwindling numbers of species were taken up to 100 m onto habitats adjacent to their own. (6) On the Moor House outcrops (2.6-21.0 m in diameter) Peat species averaged 45% (carabid) and 31% (staphylinid) of all species recorded at the centre of the site. This proportion was inversely correlated with the size (or radius) of the site for individual outcrops. (7) Limestone species taken on the outcrops showed a positive species-area relationship in keeping with island biogeographical theory. (8) Size, mobility and the relative abundance of Limestone and Peat species on the moor were instrumental in producing the overall negative carabid, but positive staphylinid species-area relationships observed on the outcrops. It is important that such factors are taken into account in the study and interpretation of faunas of habitat islands.