The Nyl River floodplain is one of the jewels in the arid Limpopo Province. The conservation and protection thereof is thus vitally important. The Nyl River Floodplain is an ephemeral floodplain and the largest of its type in South Africa. The wetland is a Ramsar site and provides habitat for a number of endangered species of birds and animals. The aims of this project were to (1) assess the water and sediment quality in the Nyl River system, (2) to determine baseline levels of pollution, (3) to develop a rapid wetland assessment protocol for biomonitoring and (4) to provide a framework for wetland management. Eighteen sites in the Groot Nyl and Klein Nyl rivers, as well as in some of the larger tributaries were selected. Water and sediment were sampled and analyzed to determine metal and nutrient levels. Bacterial analysis also took place at five of the sites along the course of the system. The results obtained from the water analysis indicate that bacterial levels in the system are cause for concern. Although metal levels in the water and the sediment are higher than Target Water Quality and Sediment Guideline Ranges, the metal levels remained relatively constant throughout the system. The metal levels indicated that they pose no potential threat to the system. The comparison between the present and historical ecological state indicated that nutrient levels are increasing in the system. The levels of toxic ammonia did not increase and thus the water quality in the system can thus be classified as fair. The sequential extraction of the sediment indicated that the majority of the metals in the sediment are not readily bioavailable. They were released by the fourth and fifth fractions and will only become available in the presence of strong reducing or oxidizing agents. Organic contaminant levels were also analysed in the sediment. The results indicated traces of PCB’s (Poly-chlorinated Biphenyls) and pyrethroids (Cypermethrin), but concentrations were too low to quantify. iii The third aim of the project was to develop a Wetland Assessment Protocol. A draft version of the protocol was developed using a modified version of the South African Scoring System version 5 (SASS5). Due to the lack of biotopes in the system, the vegetation biotope was chose as sampling habitat. Aquatic invertebrates were collected and a total score was given to each sampling site. The total site rating was determined using a combination of the SASS5 scoring system, a newly developed habitat assessment system and a human impact assessment system, The Wetland assessment protocol identified changes in water quality, but more refinement is required on a system with a greater pollution gradient. The fourth aim of the project was to set up a draft framework for wetland management. The framework is based on the National Estuary Programme of the USEPA. It has been interpreted and adapted for use in wetlands, in a similar way to which USEPA ecological risk assessment guidelines have been adapted for the South African scenario. This research project was thus able to (1) provide baseline values for the Nyl River System, (2) to produce a first draft of a Wetland Assessment Protocol and (3) provide a framework for wetland management. It is envisaged that the information in this thesis will provide useful information in the protection and management of the Nyl River. / Prof. J.H.J. Van Vuren

M.A. / Wetlands are being lost and degraded in urban areas. Urban wetlands perform a diverse range of valuable functions. The loss of wetlands, therefore, has a negative impact upon urban human populations. One of the major threats to urban wetlands in Gauteng is the development of residential and commercial developments. As prime land for development is at a premium, the urban developer has targeted wetlands, which are canalised, drained or filled before being developed over. A typical example is that of the case study used for this thesis, where a wetland found in Johannesburg, Gauteng, is in the process of being destroyed, with the developers removing wetland vegetation, levelling the site and inhibiting the flow of the Wilgespruit River. Eventually a townhouse complex to be known as Wilgeheuwel Extension 29 is to be developed on the site. An integrated sustainable rehabilitation plan is required to ensure that the Wilgeheuwel Extension 29 wetland is rehabilitated. This plan is to take into consideration all the factors that influence the wetland negatively at present, including impacts upstream and possible future impacts. Therefore, a hierarchical approach is used, where management plans for the Wilgespruit River sub-catchment, the proposed development and the individual wetland are integrated into one plan.

published_or_final_version / Architecture / Master / Master of Landscape Architecture

Thesis (M. Phil. (Environmental Law and Management) -- University of Limpopo, 2010 / According to the Ramsar Convention of 1971, Wetlands are areas of marshes, firm, peatlands or waterlogged. They are either natural or artificial. They have water that is static or flowing, fresh, brackish or salty and include areas of marine water with the depth, which at low tides does not exceed six meters. Wetlands are regarded as important ecological components of the natural environment because of their richness and ability to support life. Wetlands essentially catch, clean and preserve any water. They are able to reduce the severity of drought and floods by regulating a stream flow. They also control erosion and provide habitat for many different plant and animal species. Wetlands also serve as valuable source of water, fish and grazing for livestock. They are important nesting grounds for birds. Wetland resources are also known to be of socio-economic importance because they provide materials for furniture and craft’s work Ga-Riba wetlands are very important for the community of Ga –Riba because they provide them with food such as fish and birds. Some of the community members make baskets, hats and mats using wetlands grass. They also make pottery using clay from the wetlands. During winter the wetlands are used as areas where traditional initiation for Ga-Riba girls is perfomed. Some people own fields within the wetlands on which they cultivate vegetables, maize and other crops. They also use wetland as grazing areas for their domestic animals such as cattle and goats. The Ga-Riba wetlands are being invaded by one of the alien plant called Populus alba L (Poplar). This type of alien plant, like other alien plants disturbs the ecological stability of the wetlands. Findings of the tests conducted on soil and water indicated that Poplars are changing the nature of the soil and the water of the wetlands. Vegetation survey showed that, wetlands had less vegetation than they were supposed to. With regard to legal instruments to control the invasion of wetlands by alien plants, findings showed that there are insuffient legal instruments which can be utilized.

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The degradation of wetlands and loss of their associated ecosystem services is widely recognised in South Africa, however, at present there is no standard method of biologically assessing wetland health in this country. Internationally, particularly in the U.S.A and Australia, wetland bioassessment techniques using macroinvertebrates are well established. A number of these wetland bioassessment protocols have been derived from local river biomonitoring techniques, as there is a belief that river and wetland ecology and macroinvertebrate assemblages at family level are similar. However, some authors consider wetland macroinvertebrate assemblages and ecological processes to differ greatly from those found in rivers, and believe that such techniques are not transferable. South Africa has a well established macroinvertebrate biomonitoring protocol for rivers called SASS5 (South African Scoring System Version 5). This study is a preliminary investigation into the extent to which the SASS5 scoring system is applicable to the assessment of nutrient enriched wetland water quality. Macroinvertebrates are particularly suitable as biomonitoring tools: they respond to a variety of stressors, have life cycles that allow for integrated responses to episodic pollution, and are relatively easy to identify to family level. When selecting wetlands for the development of a biomonitoring protocol, wetlands should all be of the same; classification (Le. palustrine), geomorphological and climate setting, hydrological regime and dominant vegetation class. Sampling was restricted to sedge-dominated palustrine wetlands in the midlands of KwaZulu-Natal, with similar hydro-geomorphological settings. Due to wetlands and rivers having different biotopes (e.g. no riffles present in wetlands), the SASS5 sampling protocol could not be used, thus a pilot investigation was undertaken to derive a suitable sampling technique for \ collecting a representative and diagnostic sample of aquatic macroinvertebrates from a wetland. This technique was developed based on published methods. Both sweep net and activity trap sampling were conducted, and each evaluated for their effectiveness at macroinvertebrate collection. Sweep net sampling was tested over a range of sweep intensities (2-6 sweeps), and activity traps were placed at four different depths: at the water surface, just below the surface, 0.10.15m below surface and on the substrate. A total of 32 taxa identified to family level were identified in the samples. Taxon diversity and composition did not differ in the activity traps placed at the four depth locations. Taxon diversity did not differ significantly between different sweep intensities; however there was a significant difference in taxon composition between the different sweep intensities and between activity trap and sweep net samples (p<0.05). Sixty-eight percent of taxa appeared more frequently in sweep net sampling compared to activity trap sampling. Six taxa were found exclusively in sweep net samples, and two taxa were recorded exclusively in activity traps. There was no trend in either method collecting more or missing any unique trophic group. In conclusion, activity traps are not required to supplement sweep net data, and a technique using a sweep net with a sweep intensity of five would be suitable to collect a representative sample of wetland macroinvertebrates. Using the derived technique, four reference and three wetlands impacted by dairy effluent were sampled. Six macroinvertebrate samples were collected from each of the seven wetland, together with data for selected physico-chemical variables, macrohabitat condition, biotope suitability and organism detectability. For each sample, the macroinvertebrates were identified and assigned a predetermined SASS5 tolerance score between 1 and 15, with higher scores indicating increased sensitivity to poor water quality. 11 A total of 39 taxa, identified to family level, were collected during sampling. SASS5 scores ranged from 15-82. Five of the wetlands had mean SASS5 scores of between 46 and 59. Five of the wetlands had an intra-wetland SASS5 score range greater than 30. ASPT values ranged from 3.3 to 5.5, and few high scoring (~8) taxa were collected. There was no significant difference in SASS5 scores between samples collected above, at and downstream of an effluent discharge point within the same impacted wetland. SASS5 scores for reference wetlands were also not significantly higher than those recorded for impacted wetlands. Comparison of ranked SASS5 scores and environmental data did suggest a relationship between the variables, but was not significant. Based on the SASS5 score water quality guidelines, all sampled wetlands were considered to have impacted water quality; however, this was not supported by the macrohabitat and physico-chemical results. Possible reasons for the low SASS5 scores include: the lack of 'stones in/out current' biotopes in wetlands, lower levels of dissolved oxygen present compared to rivers, and the limited detectability of organisms due to large amounts of substrate in the samples. A wetland adaptation of SASS5 would require the reassignment of modified scores to certain taxa based on their distribution in wetlands of varying water quality. The SASS5 score level of 100 and the ASPT value of 6 (as specified in the SASS5 score water quality guidelines) were found to be inappropriate for wetlands. It is suggested that, either the range of taxa tolerance scores be increased (1 to >15), or the score level of 100 be lowered. The ASPT value should also be reduced. Although SASS5 appears unsuitable for assessing wetlands, variations in taxon composition between sampled wetlands, identified through CA analysis, suggests that macroinvertebrates are responsive to changes in wetland condition, and thus have potential as indicators of wetland water quality. Nine taxa responsive to the presence of nitrogen have been identified as being potentially good indicators. iii Further research should focus on the testing of SASS5 throughout the year, in a range of wetland types, and in wetlands moderately to severely impacted by pollutants other than dairy effluent. It is recommended that a habitat or biotope index be developed and used in conjunction with any future wetland macroinvertebrate bioassessment protocols. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2005.

Thesis (M.Ed. (Education)) - Rhodes University, 2007. / A full-thesis submitted in fulfillment of the requirements of the degree of Master of Education (Environmental Education)

The Nelson Mandela Bay Municipality (NMBM) is a semi-arid area along the southern coastline of South Africa (SA). Until recently, there was no systematic approach to research on wetland systems in the NMBM. The systematic identification of wetlands was made more difficult by the relatively large number of small, ephemeral systems that can be difficult to delineate. This has meant that fundamental knowledge on wetland distribution, structure and function has been limited and, consequently, management and conservation strategies have been based on knowledge on systems from other regions of the country. Environmental processes occur at different spatial and temporal scales. These processes have an effect on the abiotic factors and biotic structure of wetlands, resulting in inherently complex systems. The location of the NMBM provides a good study area to research some of these environmental and biological attributes at different spatial scales, due to the variability in the underlying geology, geomorphology, vegetation types and the spatial and temporal variability in rainfall, within a relatively small area of 1951 km2. Thus, the aim of this study was to determine the factors influencing wetland distribution, structure and ecosystem functioning within the NMBM. The first Research Objective of work presented here was to identify wetlands using visual interpretation of aerial photographs. A total of 1712 wetlands were identified within the NMBM using aerial photographs, covering an area of 17.88 km2 (Chapter 5). The majority of these wetlands were depressions, seeps and wetland flats. Valley bottom wetlands (channelled and unchannelled) and floodplain wetlands were also identified. A range of wetland sizes was recorded, with 86% of the wetlands being less than 1 ha in size and the largest natural wetland being a floodplain wetland of 57 ha, located south of the Swartkops River. The identified wetlands were used to create a wetland occurrence model using logistic regression (LR) techniques (Chapter 5), in accordance with Objective 2 of the study. An accuracy of 66% was obtained, which was considered acceptable for a semi-arid climate with a relatively high degree of spatial and temporal rainfall variability. The model also highlighted several key environmental variables that are associated with wetland occurrence and distribution at various spatial scales. Some of the important variables included precipitation, evapotranspiration, temperature, flow accumulation and groundwater occurrence. Wetland distribution patterns were described in Chapter 6. Spatial statistics were used to identify whether wetlands are clustered and, therefore, form mosaics within the surrounding landscape (Objective 3). Systems were found to be highly clustered, with 43% of wetlands located within 200 m of another system. Clustering and wetland presence was especially prominent in the southern portion of the Municipality, which is also associated with a higher mean annual precipitation. Smaller wetlands were also significantly more clustered than larger systems (Average Nearest Neighbour statistic, p-value < 0.0001). Average distances also significantly varied according to HGM type, with depressions being the most geographically isolated wetland type compared to the other HGM types. Overall, distances between wetlands indicated good proximal connectivity. Potentially vulnerable areas associated with wetland systems were identified successfully using landscape variables, in accordance with Objective 4. These variables were: land cover, slope gradient, flow accumulation, APAN evaporation, mean annual precipitation (MAP) and annual heat units. The existing Critical Biodiversity Network was also used in connection with these variables to further identify potentially vulnerable areas. The abiotic and biotic characteristics were decribed for three hydrogeomorphic (HGM) types at a total of 46 wetland sites (Chapter 7), as per Objective 5. Depressions, seeps and wetland flats were sampled across the different geological, vegetation and rainfall zones within the NMBM. The wetland sites were delineated up to Level 6 of the Classification System used in SA, and the various abiotic and biotic characteristics of these systems were defined. A total of 307 plant, 144 aquatic macroinvertebrate and 10 tadpole species were identified. Of these species, over 90 species were Eastern Cape and SA endemic species, as well as three threatened species on the IUCN Red List. Multivariate analyses (including Bray-Curtis similarity resemblance analyses, distance-based redundancy analyses, SIMPER analyses and BIOENV analysis in Primer), together with environmental data, were used to define community structure at an HGM level, in accordance with Objective 5. The importance of the spatial scale of the environmental data used to define plant and macroinvertebrate community structure was described in Chapter 7, to address Objective 6. The results showed that both broad-scale and site-level characteristics were important in distinguishing community structure within the HGM types that superseded general location, the sample timing or the stage of inundation. These results also indicated that a combination of both landscape and site-level data are important in defining the community structure in the various HGM types. Some of the important environmental variables that explained some of species assemblages were similar to those in the wetland occurrence model (Chapter 5), with some additional hydrological and soil physico-chemical parameters (e.g. soil electrical conductivity, soil pH, and surface and subsurface water nutrients). These significant variables indicate the complex, multi-scalar role of environmental attributes on wetland distribution, structure and function.

No description available.

The Matlabas mire, an actively peat accumulating wetland, is located in the headwaters of the Matlabas River, Marakele National Park, Limpopo Province, South Africa. Various seepage zones and artesian peat domes are contained in this peatland that consists of two tributaries of which the western one is partially channelled. The occurrence of decaying peat domes and desiccated areas with terrestrial vegetation, as well as the apparent erosion on the western tributary, have raised concerns on the health of this wetland. A network of piezometers was installed in the mire and results confirm that the system is fed primarily from seepage from the slopes of the catchment. Chemical analysis and temperature recorded indicate an isolated groundwater source of which the water does not mix with surface water. This is linked with isotope analysis of the age of peat in various sections of the mire. Erosion was attributed to anthropogenic changes in the catchment. Management recommendations include rehabilitation and reinstating the driving forces that support the mire. / Environmental Sciences / M. Sc. (Environmental Management)