Beacons in the limnological landscape

Abstract

An overview is given of a number of major developments in the limnology of South Africa, Zimbabwe and Namibia. None was possible without the involvement of enthusiastic investigators who, over some 70 years, stimulated the growth of freshwater research in these arid lands. The contributions to the nascent limnology of the subcontinent are described, beginning first with river studies from which arose a hydrobiological template. This was widely used and modified as understanding increased. Subsequently, wetlands, as well as man-made and natural lake systems, were added. Together, each of the components of this endeavour contributed to the structure of the new National Water Act, in which the intrinsic requirements of the aquatic ecosystem are stressed. This stimulated the development of management protocols for the assessment of river flows and lake levels in order to sustain the vital ecological processes within the respective ecosystems. In doing so, the old paradigm of ‘Nature in Balance' was replaced by the acceptance of not one natural state, but a series of dynamic states, particularly so in rivers.


Keywords: river zonation; regulation; impact; macroinvertebrates; Simuliidae; riverine wetlands; coastal lakes and reservoirs; suspensoids; hypereutrophication; Water Act; Building Block Method; Inflow Stream Requirements; water quality; ecosystems; temporal and spatial variation dependence
(Afr J Aqua Sci: 2003 28(2): 89-101)