Grazing impacts on soil mites of semi-arid chenopod shrublands in Western Australia

This research describes the effects on the soil mite fauna of two sheep-grazing intensities applied to chenopod shrublands in both good and poor conditions. Soil was sampled from within and between bluebush (Maireana polypterygia) accretion mounds, 9 and 18 months following a 10-year grazing trial. There were major differences in the mite assemblages associated with the grazing treatments. Heavily grazed sites had reduced abundances of most mite species and substantially reduced diversity. In this ecosystem, soil accretion mounds below bluebush are important sites of acarine diversity and abundance. Of a total of 75 species, 49% were found only in this habitat. The decline of mite assemblages associated with vegetation degradation and mound decay mirrors declining soil properties, which have been described for these sites. These soils have particularly high species richness, with broad similarities in mite composition (at family and generic levels) with similar environments elsewhere in the world, continuing the trends found by other researchers. (C) 2003 Elsevier Science Ltd. All rights reserved.