The wetlands on the eastern shore of Lake St Lucia are mainly groundwater fed and exhibit a variety of hydrological regimes that give rise to a high degree of habitat and species diversity. Given the ephemeral and episodic nature of much of the surface water on the east coast, ecological dynamics of this type are likely. Conditions on the east coast during the study were somewhat unusual, as the region experienced drought conditions during this period.
The East Coast wetlands support a variety of aquatic fauna, including at least four freshwater fish species listed as rare or threatened by the IUCN. Given the complex nature of these interactions, aquatic macrofauna on the East Coast are likely best conserved by maintaining a heterogeneous mix of wetland habitats, maintaining the diversity of structure and function of East Coast wetlands that can facilitate an element lottery in development and structure in biotic assemblages. The work described in this dissertation was carried out on the eastern shores of Lake St Lucia, KwaZulu-Natal, South Africa and at the School of Botany and Zoology, University of Natal, Pietermaritzburg, from February 2002 to December 2003, under the supervision of Prof. Rob C.
Together, these projects will provide significant insight into how the East Coast wetlands function. Mount Tabor is located on the eastern shore of Lake St Lucia, and Fanies Island on the western shore.
ACKNOWLEDGEMENTS
The wetlands on the eastern shores of St. Lucia (hereafter referred to as the 'eastern shores') are believed to be maintained by groundwater (Kelbe & Rawlins, 1992). The east coast wetlands are recognized as an integral part of the estuary system and should be included in the overall picture of the system as Lake St. Because the east coast freshwater wetlands were the subject of this study, the study area was focused on the low-lying areas of the coastal plain.
Kelbe and Rawlins (1992) provide a detailed description of the functioning of the Eastern Shores wetlands in relation to the underlying hydrology of the area. Rawlins and Kelbe (1988) suggest that the pine plantation is located west of the Mfabeni. Kelbe and Rawlins (1992) suggest that rainfall is unlikely to have any effect on the Eastern Shores aquifer unless it exceeds 10 mm, depending on the depth of the groundwater and the preceding conditions.
The results of the analysis were plotted along the first two axes of the surgery (Figure 11 and Figure 12). Enclosed in the envelope are samples taken from each of the four habitat types listed in the legend.
UTRE NYM2 CHAN
The surface waters of the East Coast were typically acidic, ranging from nearly neutral (pH 6.8) to as low as pH 2.77 (Table 7). Site scores on axis 1 of the analysis were adjusted (by multiplying by -1 and adding 5) so that an increase in the score indicates decreasing stability. Of this number, it is estimated that two-thirds of the St Lucia manatee population will use the eastern coast for grazing.
Fish were collected from ten of the 16 routine sites on the East Coast as well as an additional ten adhocsites during the course of sampling. Similar freshwater habitats exist along the length of the eastern shoreline of Lake St Lucia (TaylorS, press comm.). As a result, they were the most ubiquitous and abundant fish on the East Coast, despite the fact that their eggs are not desiccation resistant.
In the initial MDS analysis, two samples (ES051A and ESl19A) were outliers that compressed the distribution of other sites into a narrow cluster in the plot. A hierarchical cluster analysis of Bray-Curtis similarities between aquatic invertebrate orders (Figure 25) shows similar distribution of orders. Within the larger group, the separation of taxa illustrated in the MDS plots (enclosed in dotted boxes) can be discerned, although these separations occur at fairly high levels of similarity (50% to 700/0).
Examination of the db-RDA plot (Figure 27) reflects a complex relationship between the distributions of aquatic invertebrates and their environment. For the open wetlands, 52% of the taxa recorded were found only in these habitats and did not occur in the swamp forest, streams or Cyperus swamp. Some of the issues raised are also relevant in the context of the East Coast - a shallow, variable wetland.
Despite the differences between these systems and the east coasts, parallels can be drawn between them. On the eastern coasts, vegetated wetlands generally showed lower stability (Table 8) in terms of constancy of water physico-chemical conditions than other types of wetlands, namely swamp forest, streams and Cyperu swamp5. In swamp forest, 43% of the 32 taxa that occur in this habitat do not occur elsewhere.
The low specificity of the taxa found in the stream habitat is somewhat surprising, since this habitat is Given the status of the GSLWP protected area and its World Heritage listing, it is likely that the east coast.
Marcusenius macrolepidotus Anguilla sp. Schrank, 1798 Barbus bifrenatus Fowler, 1935 Barbus paludinosus Peters 1852 Barbus viviparusWeber, 1897 C/arias gariepinus (Burchell, 1822) C/arias theodoraeWeber, 1897 Aplocheilichthys katangae (Boulenger, 1912). Rotund Brown Dytiscid Dytiscidae Hydroporinae Herophydrus Sharp 1882 sp.1I Debelo rjava Dytiscid Dytiscidae Hydroporinae Herophydrus Sharp 1882 sp. Majhna zlatoprogasta dytiscid Dyliscidae Laccophilinae Laccophilus Leach 1815 sp.IV Drobna zlatoprogasta dytiscid Dytiscidae Laccophilinae Laccophilus Leach 1815 sp.V Brown&Tan Noterid Dytiscidae Noterinae.
Small brown notrid Dytiscidae Noterinae Canthydrus Sharp 1882 sp.IJ Yellow shoulder notrid Dytiscidae Noterinae Canthydrus Sharp 1882 sp. Bicolor notrid Dytiscidae Noterinae Hydrocanthus Say 1825 sp.IJ Large brown notrid Dytiscidae Noterinae Hydrocanthus Say 1825 sp.
