More than 90% of wetlands in the Upper South East of South Australia have been lost, primarily through drainage and clearing vegetation for agriculture. Over the last 20 years, temporary, semi-permanent and permanent wetlands have been, and continue to be, hydrologically restored to enhance and maintain biodiversity. / In this study, habitat in four seasonal temporary wetlands in the Watervalley Wetlands complex, in the Upper South East, was manipulated to determine the potential for natural regeneration and human-induced restoration techniques. The seed banks of three wetlands were studied using the seedling emergence technique and I compared the composition of seed banks and the history of disturbance in these wetlands. The seed bank in the Parkhill wetland contains introduced amphibious and terrestrial plants as well as a suite of native species. Experiments using soil from the Parkhill wetland revealed that the dominant species found in the threatened vegetation association, Selliera radicans herbland, could be restored by transferring soil. The seed bank in Mrs White Lagoon lacks amphibious and terrestrial species. The seed bank in Jaffrays Lagoon is in good condition with an absence of introduced species and a suite of amphibious, submerged, emergent and terrestrial species. Therefore, Jaffrays Lagoon was identified as a donor wetland, from which soil could be transferred to nearby wetlands that have been hydrologically restored, to introduce a suite of plant species and accelerate succession in plant communities. / Soil was transferred from Jaffrays Lagoon to three plots in Mrs White Lagoon to determine the potential for accelerating succession. Biomass of submerged species increased significantly in the first growing season, during a submerged water regime. Further studies are recommended to trial this technique in waterlogged conditions with the aim of triggering the germination of emergent and amphibious species. / In a controlled experiment, in the Mandina Marshes, sedges were subjected to rotary-hoeing, slashing and slashing and removing the clippings to create a mosaic of open water and vegetation. Such a mosaic may enhance waterfowl habitat. The responses of aquatic invertebrates, specifically early colonisers, to the vegetation treatments were measured to determine the potential effects on the invertebrate components of waterfowl diets. Results indicate that rotary-hoeing sedges in the Madina Marshes may increase diversity and evenness of early colonisers without reducing the total abundance of aquatic invertebrates. By contrast, slashing and slashing and removing the clippings appears to reduce both diversity and abundance of early colonisers. / An exclosure was constructed in a section of riparian and littoral habitat in the Parkhill wetland to test the response of plant communities to the cessation of grazing by sheep and cattle. In the first 12 months, Melaleuca species returned, species richness and diversity indices decreased and the biomass of vegetation increased in the littoral zone but not in the riparian zone. Variables other than the cessation of grazing probably contributed to these results and recommendations are made for the first 10 years of a monitoring program. / Recommendations for future wetland restoration and ongoing management of the Watervalley Wetlands are provided, based on the outcomes of these experiments. / Thesis (MApSc(EnvironmentRecreationMg))--University of South Australia, 2003.
| Identifer | oai:union.ndltd.org:ADTP/267638 |
| Creators | Birrell, Michaela Anne |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | copyright under review |
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