The wetlands on the Eastern Shores of Lake St Lucia are primarily groundwater
fed and exhibit a variety of hydrological regimes that give rise to a high degree of
habitat and species diversity. Hydrologically unstable systems experience
ecophasal shifts that can disrupt an established steady state within the wetland
ecosystem. Communities of both plants and animals can accordingly disintegrate
into more or less isolated populations, open to re-invasion by preceding or "new"
species when conditions change again. Given the ephemeral and episodic nature
of much of the surface water on the Eastern Shores, ecological dynamics of this
type are likely. Fish and aquatic invertebrates were sampled from a number of
routine and other sites between May 2002 and April 2003. Measurements of
various environmental and abiotic factors (including pH, ionic conductivity and
dissolved oxygen levels) were taken with each sample in order to establish
relationships between environmental changes and the assemblages of aquatic
fauna occurring within the Eastern Shores wetlands. Conditions on the Eastern
Shores during the study were somewhat anomalous, as the region experienced
drought conditions during this period. The Eastern Shores wetlands support a
diversity of aquatic fauna, including at least four species of freshwater fish listed
as rare or threatened by the IUCN. The aquatic organisms existing within this
dynamic system exhibited changes in abundance and distribution that reflected
the spatial and temporal changes in their environment. The relationships between
aquatic organisms and their environment were complex, with assemblages being
affected by combinations of changing environmental and habitat variables as well
as other factors such as the environmental stability of habitats and stochastic
effects. Given the complex nature of these interactions, aquatic macrofauna on
the Eastern Shores are likely to be best conserved through the preservation a
heterogeneous mix of wetland habitats, maintaining the diversity of wetland
structure and function on the Eastern Shores that can facilitate an element of
lottery in the development and structure in biotic assemblages. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2004.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ukzn/oai:http://researchspace.ukzn.ac.za:10413/5595 |
| Date | January 2004 |
| Creators | Vrdoljak, Sven Michael. |
| Contributors | Hart, Rob C., Ellery, William N. |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | English |
| Type | Thesis |
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