Tshikae, Balatlhane PowerDavis, Adrian L.V.Scholtz, Clarke H.2013-10-022013-10-022013Tshikae, BP, Davis, ALV & Scholtz, CH 2013, 'Species richness - energy relationships and dung beetle diversity across an aridity and trophic resource gradient', Acta Oecologica, vol. 49, no. 5, pp. 71-82.1146-609X (print)1873-6238 (online)10.1016/j.actao.2013.02.011http://hdl.handle.net/2263/31876Understanding factors that drive species richness and turnover across ecological gradients is important for insect conservation planning. To this end, we studied species richness e energy relationships and regional versus local factors that influence dung beetle diversity in game reserves along an aridity and trophic resource gradient in the Botswana Kalahari. Dung beetle species richness, alpha diversity, and abundance declined with increasing aridity from northeast to southwest and differed significantly between dung types (pig, elephant, cattle, sheep) and carrion (chicken livers). Patterns of between-study area species richness on ruminant dung (cattle, sheep) differed to other bait types. Patterns of species richness between bait types in two southwest study areas differed from those in four areas to the northeast. Regional species turnover between study areas was higher than local turnover between bait types. Patterns of southwest to northeast species loss showed greater consistency than northeast to southwest losses from larger assemblages. Towards the southwest, similarity to northeast assemblages declined steeply as beta diversity increased. High beta diversity and low similarity at gradsect extremes resulted from two groups of species assemblages showing either northeast or southwest biogeographical centres. The findings are consistent with the energy hypothesis that indicates insect species richness in lower latitudes is indirectly limited by declining water variables, which drive reduced food resources (lower energy availability) represented, here, by restriction of large mammals dropping large dung types to the northeast and dominance of pellet dropping mammals in the arid southwest Kalahari. The influence of theoretical causal mechanisms is discussed.en© 2013 Elsevier Ltd. All rights reserved. Notice : this is the author’s version of a work that was accepted for publication in Acta Oecologica.Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Acta Oecologica, vol. 49, no. 5, 2013, doi : 10.1016/j.actao.2013.02.011Aridity gradientBotswana KalahariDiversityEcotoneScarabaeinaeSpecies richnessTrophic gradientDung beetlesInsects -- EcologyPostprint Article