Successional changes in rehabilitating coastal dune communities in northern KwaZulu/Natal, South Africa

Post-mining habitat rehabilitation of coastal sand dunes north of Richards Bay by Richards Bay Minerals commenced in 1978. The reshaping of dunes followed by the spreading of topsoil collected ahead of mining, results in the development of a series of known aged habitat types, varying from young communities dominated by low growing sweet thorns, Acacia karroo, to forests dominated by sweet thorns, with broad-leaf trees characteristic of the surrounding indigenous forests establishing themselves. The simultaneous availability of a known-aged series of habitats provides an opportunity to relate temporal changes in selected plant and animal communities to changes in habitat variables. Studies on millipedes, rodents and birds revealed taxon specific increases in species diversity and in species richness and changes in density with an increase in habitat age. Comparisons of age specific community variables on rehabilitating dunes with those recorded in relatively undisturbed dunes suggest that the development of communities result from autogenic succession initiated through habitat rehabilitation. Several community parameters in the oldest rehabilitating dune forests are similar to those recorded in undisturbed forests. It is concluded that biological diversity can be restored through management options based on principles relating to ecological succession.