South African estuaries are essential biodiversity hotspots. At the same time, they serve as foci for development, tourism, and recreation, and their biological resources support subsistence and commercial fisheries. Human activities have caused the health and provision of ecosystem services in several estuaries to decline. This study assessed efforts to restore normal functioning in degraded estuarine lakes (St Lucia and Nhlabane) and temporarily closed estuaries (Mdloti and Mhlanga). These systems have been impacted by reduced freshwater inflow and the effects of urban, industrial, agricultural, and mining activities. Restorative efforts included breaching the estuary mouth, using artificial structures to restore tidal action (Zandvlei), and constructing canals to re-establish water flows (Isipingo, Zeekoevlei). The success of these efforts has been varied. In a few cases (Great Brak, Zandvlei), restoration removed negative pressures and the estuary recovered but, in most cases (e.g. Isipingo and Siyaya), restoration efforts failed. The assessment highlights the importance of identifying and addressing the root causes of deterioration instead of focusing on measures to fix the symptoms. For example, frequent artificial breaching of small closed estuaries can exacerbate poor health by causing sedimentation and shallowing. Restoring normal freshwater inflow is a more effective solution. This critical assessment showed that most rehabilitation attempts have been unsuccessful and a coordinated national effort supported by appropriate human and financial resourcing is needed. A socio-ecological systems approach for the restoration of estuaries and delivery of multiple ecosystem services is outlined that provides opportunities for job creation and contribution to the blue economy.
Audio/Video, Conference Presentation, SER2019
Society for Ecological Restoration