The use of remote sensing for monitoring environmental indicators: The case of the Incomati estuary, Mozambique

摘要: Abstract The Incomati river basin is a transboundary shared by three countries: South Africa, Mozambique and Swaziland. To assess the water requirements of environment, as stated in Tripartite Interim Agreement (TIA) signed riparian countries Johannesburg 2002, needs to monitor ecological state river, including estuary. A monitoring system has be established that can evaluate environmental fresh based on appropriate indicators reflect health estuary important functions but it also an socio-economic resource. Local communities depend estuary’s natural resources. Modifications flow regime upstream developments impact productivity estuary, diminishing fish shrimp production, reducing biomass vegetation such grasses, reeds mangroves increasing salt intrusion. decrease consequently affects incomes living conditions these communities. Based understanding effects different pressures ecosystem some for are suggested, extent vitality mangrove forests. This latter indicator further elaborated paper. Remote sensing techniques were used identify quantify forests two selected areas (Xefina Pequena Island Benguelene Island). Five satellite images covering period 20 years (1984–2003) showed area covered non-degraded significantly decreased both islands, 25% Xefina 40% Island. Moreover, study reflection using NDVI significant decline densities over last years. Possible causes changes reviewed: rainfall trends, modifications regime, harvesting levels woods. findings presented this paper show relevant which assessed means remote techniques. Follow-up research required will establish relative importance causal factors estuarine It concluded remotely sensed may provide data system.