Wetlands on the extensively afforested Tsitsikamma Plateau are prone to fire and according to foresters, they behave as fire channels that under bergwind conditions rapidly carry fire into plantations. The destruction of plantations causes great economic loss and MTO would therefore prefer to afforest some smaller wetlands to limit the fire hazard. This study was carried out in the middle of a drought period and sought to determine the influence of fire, plantation management and the environment on wetlands and its component species. This study of palustrine wetlands on the Tsitsikamma Plateau identified five wetland vegetation communities, in which plant species richness was relatively low. Plant compositional structure of wetlands is influenced by wetland location, the height of the adjacent plantation and fire frequency. This study found a pronounced plant species turnover from west to east and soil coarseness increased along the same gradient. Re-sprouters dominated the wetland communities in the Tsitsikamma but a few populations of the obligate re-seeding ‘Near threatened’ Leucadendron conicum rely on fire for rejuvenation purposes. Regarding dragonflies in wetlands, abundance was found to be low, while species richness was relatively high considering the absence of surface water. The study found that fire indirectly influenced dragonfly abundance and species composition by altering vegetation structure. Dragonfly abundance and species richness was generally higher in wetlands with older vegetation (≥ 9 years). Further, most dragonflies frequenting the palustrine wetland habitats were females. Seeing that female dragonflies spend most of their time away from prime breeding habitats to escape male harassment, the study indicated these wetlands as important refuge habitats for them. Dragonfly abundance is expected to increase once the drought ends; however, the overall patterns observed are likely to remain unchanged under wetter conditions. Narrow wetlands (< 10 m) are few on the plateau and it is not advisable to sacrifice wider wetlands in the Tsitsikamma. Further, with regards to ecological processes and wetlands’ influence on the surrounding Tsitsikamma matrix, more research is needed before wetlands may be sacrificed. To deal with the fire risk the Tsitsikamma environment poses to plantations, it is strongly recommended to establish and maintain a cleared buffer area between plantations and wetlands. Further, for vegetation rejuvenation purposes, it is important to burn wetlands at irregular intervals but not more frequently than every nine years and not less frequently than every 25-30 years.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nmmu/vital:10747 |
| Date | January 2011 |
| Creators | Hugo, Christine Denise |
| Publisher | Nelson Mandela Metropolitan University, Faculty of Science |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MSc |
| Format | 81 p. : col. maps, pdf |
| Rights | Nelson Mandela Metropolitan University |
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