Invertebrates or iron: does large-scale opencast mining impact invertebrate diversity in ephemeral wetlands?

Disturbance has been offered as an explanatory mechanism in structuring the variation of species across a landscape. In this study, we investigated the effect of the impact by Kolomela Iron Mine on the variation of species occurring in temporary pans. Using a novel null model approach to partitioning two sets of data (from before and after the establishment of the mine) into independent alpha (α) and beta β components, we determined that the mining practices have had little to no impact on the invertebrate diversity. This suggests that these communities were more resilient than previously assumed. The results were, however, confounded by the fact that the resting eggs of pan inhabitants could remain dormant in the sediment for decades; suggesting that observed diversity patterns were possibly remnants of unknown past events. To ensure that the effects of present-day impacts are assessed, continuous monitoring is recommended. Similarly, the preservation of conservation areas and a landscape wide management system were proposed to ensure that large-scale ecological process are not jeopardized by the gradual fragmentation of the pan metacommunity.Key words: branchiopod crustaceans, disturbance, diversity partitioning, null-model