oa African Entomology - Alpha-diversity patterns of dung beetle assemblages (Coleoptera: Scarabaeidae, Aphodiidae, Staphylinidae, Histeridae, Hydrophilidae) in the winter rainfall region of South Africa : short communication
The alpha diversity of six higher taxa (family or subfamily) of dung beetles at 11 study sites in the southwestern Cape, South Africa, has been compared using indices, cluster analysis, rank species abundance plots and goodness of fit by diversity models. The six higher taxa showed several different patterns of species richness and evenness between indigenous shrubland and recently created pasture habitats. In each habitat, a trend from lower to higher species richness in both coprophagous (Oxytelinae to Aphodiidae to Scarabaeinae/Coprinae) and predatory taxa (Hydrophilidae to Histeridae to predatory Staphylinidae) was paralleled by a trend from lower to higher evenness shown by the reciprocal of the Berger-Parker dominance index. The reciprocal of this index showed a significant positive correlation to species richness. Cluster analysis of 10glO rank species abundance sequences (low variance) for the entire data set (six higher taxa x 11 habitats), which emphasized species richness, seemed to characterize similarities in diversity between species assemblages better than cluster analysis of the same data set converted to percentage abundance (higher variance) which emphasized dominance. Groups of assemblages with low species richness which mostly showed peak abundance during relatively unfavourable periods in the cool, wet, early spring (high abundance, Oxytelinae) or warm, dry summer (lower abundance, Hydrophilidae) were consistently well descriptionbed by the geometric series model. Groups of assemblages which showed higher species richness and moderate abundance and which were principally active during the more favourable mild, moist conditions of late spring, were best descriptionbed by the logseries and lognormal models. These results have been compared with others from the winter rainfall region of Europe and the summer rainfall regions of South Africa and Australia.
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