Does estuarine health relate to catchment land-cover in the East Kleinemonde system, South Africa?

Abstract

Temporarily open/closed estuaries in South Africa are being subjected to varying degrees of catchment land-cover transformation. Natural landscapes and hydrological functions are integral to the functioning of estuaries. The relationship between catchment land-cover and the health of the East Kleinemonde Estuary was investigated between 2011 and 2013, using geographic information system (GIS) techniques to delineate and quantify land-cover in the whole catchment, in the lower section of the catchment, and in the 1 km and 100 m buffer zones surrounding the estuary. Human activities, as outlined by the Department of Water Affairs resource directed measures (RDM) studies, and their associated land-cover classes are described. Possible links between catchment and buffer zone land-cover class composition and the health of the East Kleinemonde Estuary were explored. There was a relationship between catchment land-cover and estuarine health within all assessed catchment delineations. Natural land-cover was determined to be the best predictor of estuarine health for the East Kleinemonde system. The methods employed in this study can be applied to other temporarily open/closed estuaries in South Africa to prioritise these systems for rehabilitation and/or conservation.

Keywords: buffer zone analysis, estuarine management, estuary conservation, GIS, natural land-cover

African Journal of Aquatic Science 2014, 39(4): 395–402