The regeneration of soil micro-arthropod assemblages in a rehabilitating coastal dune forest at Richards Bay, South Africa

The structure and composition of the soil micro-arthropod communities of five postmining rehabilitating sites (between 1 and 24 years after rehabilitation) are compared with that of an undisturbed dune forest benchmark. We extracted soil micro-arthropods (Acari and insects) with a modified Berlese-Tullgren funnel and used soil carbon, calcium, potassium, magnesium, nitrogen, sodium, phosphorous and acidity (pH) as explanatory variables of micro-arthropod community composition. Acari accounted for the majority of all the micro-arthropods (between 65 and 97% of the sample) at the different sites. Density, richness, diversity and composition showed significant differences between the unmined benchmark site and the rehabilitating sites for both insects and Acari, with weak habitat-age related patterns. Canonical Correspondence Analysis suggests that differences between samples from regenerating sites and those from the benchmark sites slowly decrease with increasing regeneration age, but that community composition is only weakly related to soil properties. Our results suggest that coastal dune forest rehabilitation could give rise to the regeneration of micro-arthropod assemblages, but it may take a long time. Therefore, potential limiting factors for community regeneration need to be identified to improve the chances for successful restoration.