Abstract
M.Sc.
Mpumalanga, “the place where the sun rises”, sets the scene for one of the rarest
wetland types in South Africa. They are formed on one of the last remnants of the
ancient African land surface, contain peat and together with a variety of other pan
types make up the Mpumalanga Lakes District. Of these approximately 320 pans,
only ±2.3% are reed pans. These endorheic wetlands are unique from other pan
types and peatlands in South Africa and support an abundant biodiversity. They
perform vital functions such as water storage, filtering out impurities and carbon
fixation, which prevents an excess release of CO2 into the atmosphere. There is
very little known about these endorheic wetlands and thus they are constantly
being threatened by various activities such as agriculture, livestock and mining.
The objectives of this study were to determine the spatial and temporal variation
of macroinvertebrate community structures of reed pans and the environmental
factors, such as water quality, responsible for the maintenance of these
structures; to determine the best method for sampling aquatic invertebrates in
reed pans; as well as to determine the relationship between aquatic invertebrates
and the water, sediment and habitat quality of a reed pan. Together with this the
amphibian diversity as well as the occurrence of other biotic components was
determined.
Four reed pans were assessed during four different seasons over a one year
period to account for the different hydrological extremes. Sub-surface water
samples were analyzed for their suspended solid content, nutrient levels, metals
and chlorophyll-a concentrations as well as in situ water quality parameters.
Sediment samples were analyzed for metal concentrations, organic carbon and
water content, as well as sediment size distribution. Invertebrates were collected
using the following sampling techniques: aquatic light trap, terrestrial light trap,
emergent trap, sweep net, plankton net, as well as benthic sampling using an
Eckman grab.