Restoring degraded landscapes in lowland Namaqualand:: Lessons from the mining experience and from regional ecological dynamics

Three-quarters of a century ago diamond mining was added to livestock grazing and cereal cropping as a serious cause of landscape degradation in the north-western semi-arid region of South Africa, Namaqualand. Since that time the activities of diamond mine operators and prospectors have eclipsed all other land uses as a cause of degradation in this region. Discontinuous patches along virtually all of the 400 km of the Namaqualand coastline have been, or are currently, being mined or prospected. Prior to 1992 little was done to restore the landscapes and ecosystems to their pre-mining state, but since then legislation has placed a clear responsibility for restoration on mining operators. Implementation of ecological restoration was initially slow, but has recently gained momentum, in line with a growing awareness of environmental responsibilities amongst the global mining industry. In general, autogenic recovery of the perennial vegetation does not take place. The low annual rainfall and prevailing strong windy conditions present the greatest climatic challenges to the restoration of the flora. While the unique vegetation, and its features (e.g. poor representation of perennial species in the seedbank) present challenges to understanding the interventions that are critical in achieving ecological restoration. At the same time, climatic conditions such as the strong seasonality and low variability of rainfall, together with floristic features such as the high incidence of succulence, and the extraordinary drought tolerance of many seedlings, present opportunities for restoration. Perhaps the greatest challenges to restoration derive from the unsuitability of much of the mined overburden soils for plant growth. The nature and importance of climatic conditions, mined soils, topsoils, soil nutrients, landscaping, seedbanks, seeding, transplantation, and the interactions between these and other factors are evaluated in the context of this semi-arid environment and the prevailing mining practices. (c) 2006 Elsevier Ltd. All rights reserved.