Multi-temporal reconstruction of long-term changes in land cover in and around the Swartkops River Estuary, Eastern Cape, South Africa

Multi-date remotely sensed images comprising Landsat TM images of 1984, 1993 and 2003 and, Landsat OLI images of 2013 were used to reconstruct long-term changes in land cover in the Swartkops River Estuary by mapping changes in vegetation distribution over a period of ~ 30 years between 1984 and 2013. These images were complemented by high-resolution near-anniversary aerial photographs that were used as ancillary sources of ground truth during supervised classification of the Landsat images. Results of our investigation point to human-induced loss of biodiversity due to persistent encroachment of different development activities on terrestrial vegetation, substantial expansion of the salt marsh due to climate change-driven relative sea level rise and persistent increase in keystone salt marsh vegetation species notably Zostera capensis and Spartina maritima due to the combined influence of human-induced nutrient loading into estuarine water and relative sea level rise. These observations argue for the immediate need to embrace appropriately informed management interventions in order to enhance the sustainability of salt marsh ecosystems for the benefit of present and future generations.