Scorpion diversity along a strong environmental gradient and an evaluation of sampling protocols

Scorpions are an important component of the ground-dwelling invertebrate fauna, and may have value as indicators of ground-dwelling invertebrate diversity. However, some level of understanding of which factors influence patterns of their distribution and diversity is necessary prior to any investigation of their use in conservation planning and as indicators. This project details scorpion diversity patterns in the western Soutpansberg along a north-south altitudinal transect. Scorpions were collected by active searching at all 11 sites along the gradient. A total of 267 scorpions in 16 species, 8 genera and 3 families were recorded. Species distribution was heavily (66 % of variation) affected by soil temperature, proportion of bare ground and rock content of the soil. Species richness peaked at mid-elevations and two endemic taxa were restricted to the mid and higher elevations. Although half the effort was invested in sampling at night, active searching at night was more effective than daytime sampling. This study provides the first quantitative estimate of scorpions along an altitudinal transect in South Africa that could form the basis of a predictive framework for scorpion diversity in the Vhembe region. Keywords: Center of endemism, Scorpiones, mid-domain effect