Browsing by Author "Kotze, Donovan Charles."

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A review of the fluvial geomorphology monitoring of the receiving streams of the Mooi-Mgeni [River] Transfer Scheme Phase 1.
(2009) Hunter, Alistair Malcolm Scott.; Kotze, Donovan Charles.; Dent, Mark Clifford.; Archer, Lynette Deborah.
The Mgeni River is the major water resource for the eThekwini Metropolitan and Msunduzi Municipalities. At the end of 2002, the Mooi-Mgeni Transfer Scheme Phase 1, which transfers water from the Mooi River into the Mgeni catchment to augment the water supply to this region, was completed. The interbasin transfer of water resulted in the loss of habitat, erosion of the stream channel and transformation of the riparian zone in the receiving streams. Stream regulation resulting in an altered flow regime is considered the greatest threat to a riverine environment. An Environmental Management Plan (EMP), incorporating fluvial geomorphological monitoring procedures, was implemented to monitor the impact of the transfer on the receiving streams, the Mpofana and Lions Rivers, and to determine the rate and magnitude of erosion. A comparison of the geomorphological monitoring procedure of the EMP with best practice geomorphological monitoring derived from a review of the national and international stream geomorphological literature was conducted in this study. In addition, the implementation of the EMP geomorphological monitoring procedures was described and onsite observations of physical impacts on the receiving streams were completed. The geomorphological monitoring of the EMP included the use of erosion pins, survey of stream cross-sections and fixed-point photography. Photographs and data were collected from February 2003 to June 2006. The comparison of these monitoring methods against stream assessment best practices revealed the strengths and weaknesses of the geomorphological monitoring implemented in the receiving streams. Several key weaknesses were revealed. Firstly, an inadequate number of stream cross sections was included in the monitoring procedures. Secondly, although the erosion pins indicated some general trends in the erosion of the stream channel, they did not give a true impression of the rate and magnitude of change in slope and channel width of the stream, and the location of the erosion pins sites did not take into account the actual direction of flow during transfer as erosion pin sites were selected during low flow conditions. In addition, it was difficult to determine whether the erosion pins had been lost due to erosion or to turbulence. The results were difficult to assess and did not show whether the erosion was localised at the pins or the section of bank or stream profile. Thirdly, analysis of platform changes in the stream channel (e.g. through a comparison of aerial photograph sets) was lacking and no attempt was made to integrate the results from the different methods. Overall, the study concluded that the geomorphological monitoring of the EMP was limited, and it did not highlight the rate and magnitude of erosion in the receiving streams. Based on the findings of this study, recommendations are provided for geomorphological monitoring of the receiving streams of the Mooi Mgeni Transfer Scheme.
Burning wetlands: the influence of fire on wetland vegetation structure and composition.
(2013) Luvuno, Linda.; Kirkman, Kevin Peter.; Kotze, Donovan Charles.; Morris, Craig Duncan.
Water is a very important component of the natural world and human survival but water sources (river systems and wetlands) are becoming increasingly degraded and less functional. In particular the increase of woody C3 species into wetlands is a cause for concern, as they invade wetlands which are predominantly herbaceous. Woody species use more water than herbaceous species and this impacts wetland function. In moister savannahs and grasslands woody species are influenced significantly by fire, and fire is consequently used widely as a means of reducing woody plant density. However, in wetlands there is uncertainty about the effectiveness of fire in combating woody plant encroachment and the general impact of fire. The Kwambonambi wetlands of South Africa have been recently experiencing an invasion by woody species which are both indigenous and alien. This area was historically herbaceous and experienced frequent natural fire but is now largely under timber plantation and thus fire has been mainly excluded. This has led to a continual increase of woody species into the wetland and has seen a change from mainly herbaceous to a matrix of fern, herbaceous grasses and sedges and an invasion of swamp forest species such as Macaranga capensis. This has now affected ecosystem functions and changed fire behaviour in these wetlands. A search through the literature has revealed a lack of studies which investigate the influence of fire on wetland structure and composition. This ambiguity highlights the need for more focused research that will influence management decisions. In order to develop meaningful management strategies, there needs to be a good understanding of the problem and the underlying processes contributing to the degradation and loss of the system you are trying to manage, in this case it is wetlands. This study investigates wetland changes and losses at a small spatial and temporal scale for informing management on the best use of fire on wetlands. A temporal study (a change detection analysis) reveals that the main drivers of the vegetation structure in this landscape are the land use/land cover change in the form of large scale plantation forestry coupled with fire suppression. 92.4% of the landscape has been altered with the greatest degree of change in this landscape accounted for through the change from grassland and herbaceous wetland (1519ha and 524ha loss respectively) to timber plantation and the spread of indigenous forest indicated by an increase of 70% and 11% increase respectively. The large scale plantation forestry in the landscape has led to the drying of the landscape (which affects the hydrology of the wetlands) and therefore reduces the levels of soil saturation. Simultaneously, plantation forests are fire suppression areas to avoid tree loss. These factors, together with the disturbance of converting wetlands into plantation forest and clear felling (which occurred to 7%/155ha of the wetlands in the study site), have allowed forest species such as the fern Staenoclina tenuifolia and Macaranga capensis to invade the wetland areas. Over time, the combination of fire suppression, disturbance and drying encourages the establishment of woody seedlings, turning wetlands into swamp forests/woodlands. This regime shift is more evident in wetlands which were once converted into plantation forest with insufficient woody plant species control to accompany the withdrawal of plantation. The few wetlands which have maintained their herbaceous structure and function are those maintained with fire as a management strategy. A burn experiment shows that fire does have a significant negative effect on tree density in these wetlands-especially previous disturbed wetlands. The recommendation from this study is to remove the forest species out of the wetlands and reintroduce fire (biennial burns) into the management of these wetlands. A better relationship between the forest managers and researchers is recommended to continually co-adapt to any changes occurring in these wetlands.
The cumulative effect of wetland degradation on water quality at a landscape scale.
(2009) Jaganath, Charissa.; Ellery, William Nolan.; Ahmed, Fethi B.; Kotze, Donovan Charles.
Wetlands have been described as “one of the most globally threatened and important ecosystems”, with most wetlands providing a variety of important ecosystem services, including water quality enhancement. Despite their importance the loss of wetlands is more rapid than that of any other ecosystem, which is of particular concern in South Africa, where many communities are directly and indirectly dependent on wetlands for survival. Two useful wetland assessment tools are currently used in South Africa, but a system that assesses the extent to which wetland ecosystem services (water quality enhancement in particular) are lost as a result of wetland degradation in a landscape context does not currently exist. This study therefore aims to develop a method to determine the cumulative effect of wetland degradation on water quality, which involves the exploration and integration of a number of issues, including land-cover and its effects on water quality, wetland health and its influence on the provision of ecosystem services such as water quality enhancement, and the spatial configuration of wetlands in a landscape, and its effect on water quality at a landscape scale. The method that has been developed is applied to a case study that comprises a quaternary catchment of the upper reaches of the Goukou River Wetlands in the Western Cape of South Africa. Prioritisation criteria are also explored in a series of scenarios, and the criterion and rehabilitation method that gives the best outcome in terms of water quality enhancement is applied to the case study catchment. The workings of the method are scrutinized and benefits and limitations are subsequently highlighted. An important benefit of the methodology is that many previously inadequately explored issues are integrated into a single tool that allows for prioritisation of wetlands for rehabilitation and conservation. This was achieved with South African contexts in mind. Limitations include poor responses by potential questionnaire respondents, while the scope of the study limits the inclusion of detailed aspects which would have further enhanced the accuracy of the tool and of the level of water quality enhancement explored. The methodology that is developed in this research has also not been applied to catchments with good long term water quality data in order to improve its validity. Recommendations for future research are made, which include possible refinement of the system by accounting for factors not included in the current methodology, validation of the system by applying it to a catchment with good water quality data, and the creation of software to make the system easier to use.
The effect of the Lions River floodplain on downstream water quality.
(2015) Ndlovu, Hlengiwe.; Jewitt, Graham Paul Wyndham.; Kotze, Donovan Charles.
Wetlands provide important ecosystem services, including the purification of water. The uMngeni catchment is an important basin providing water to the cities of Pietermaritzburg and Durban, South Africa’s second largest economic hub. However, there are rising concerns over the deterioration of water quality in Midmar Dam, a large impoundment within this basin. The Lions River, one of the main tributaries to Midmar Dam, transports pollutants from its catchment, as well as the Mooi River catchment through the recently implemented Mooi-Mgeni transfer scheme (MMTS) into the impoundment. This study aims to establish a baseline ecological integrity and effect on downstream water quality of the Lions River floodplain, an important, but degraded, wetland in the uMngeni catchment, to provide a guide for the planning and implementation of rehabilitation interventions. A comprehensive assessment of the wetland’s structure was undertaken using vegetation and soil parameters, mapped and compared with an interpretation of landuse change within the wetland based on historical aerial photographs. The wetland’s impact on downstream water quality was assessed by sampling water at various points in the Lions River channel through the floodplain over a period of one year. The study found that the wetland’s ecological integrity has decreased due historical landuse in the floodplain. A comparison of soil wetness indicators which reflect the historic extent of the floodplain and vegetation wetness indicators which reflect the current extent of the floodplain suggest that although localised drying out of some areas has occurred, most of the historical floodplain area still supports wetland conditions. Wetness indicators of soil and vegetation indicate a transformation in the wetland’s water regime. A moderate to high abundance of ruderal and alien invasive species in 61% of the floodplain, particularly the drier areas of the floodplain, further indicate a reduction in ecosystem health. Hydrological processes emerge as the key drivers of species composition and historical landuse in the floodplain. Water quality results indicate that total oxidised nitrogen decreased from upstream to downstream whilst ammonia concentrations remained stable at all the sampling points. Soluble reactive phosphorus concentrations increased, while total phosphorus concentrations decreased from upstream to downstream. This study highlighted the importance of detailed field studies and understanding for rehabilitation planning to return ecosystems to their natural function.
The potential effect of wetland rehabilitation on wetland ecosystem goods and services : an investigation of three South African case studies.
(2006) Nkosi, Mncedi Rainel.; Kotze, Donovan Charles.
Wetlands supply very diverse and important goods and services to society. Goods are tangible resources, e.g. harvestable resources, cultivated foods, water for human use, cultural significance, tourism and recreation, and education. Services are less tangible and include: flood attenuation, streamflow regulation, sediment trapping, phosphate and nitrate assimilation, toxicant assimilation, erosion control, carbon storage and biodiversity maintenance. The literature reviewed confirms that these goods and services are dependent to varying degrees on the hydrology of a wetland. Dependence is due to the fact that hydrology is probably the single most important determinant of the establishment and maintenance of specific types of wetlands and process occurring in wetlands. Ecosystem goods and services are normally lost during degradation of a wetland and to restore them is a challenge. Causes of degradation could result from chemical, biological and physical processes. In South Africa physical processes such as gully erosion are one of the greatest causes of wetland degradation. Wetland rehabilitation generally seeks to retrieve the natural water regime or hydrology of a degraded wetland, with the aim of retrieving the ecosystem goods and services that were lost during degradation. The literature shows that there is a clear link between wetland rehabilitation, hydrology and ecosystem goods and services. To better understand this relationship, three selected South African wetlands were examined. The water tables and hydrological zonation of these wetlands were described and WET-EcoServices was used as a means of determining wetland functionality and assessing likely changes in function as the result of altered hydrology. The hydrological zonation of the Pelham wetland and portion 2 of the Craigieburn wetland were similar in terms of water table depth and hydrological zonation (the temporary, seasona.1 and permanent zones were represented), while portion 1 of the Craigieburn wetland had a much lower water table and degree of wetness (only the temporary zone was represented), which appears to be due to degradation. The general trend found in the second wetland is that the water table became lower towards the erosion head cut at the downstream end of the wetland. Applying a WET-EcoServices assessment shows that the first site (Pelham wetland) and portion 2 of Craigieburn wetland, which had similar hydrology, showed similarities in terms of hydrological services, such as nitrate and toxicant assimilation, that are dependent on a high degree of wetness. This dependence is due to hydrologic conditions that influence nutrient cycling, nutrient availability and rates of organic matter decomposition. In terms of goods, all three sites were important for research. Except for recreation, Pelham wetland provided little other direct benefits. In contrast, portion 1 and 2 of Craigieburn were very important for providing cultivated foods, which contribute significantly to the food security of the many poor households who use the wetland. However, portion 1 of Craigieburn was less important than portion 2 of Craigieburn for supplying natural resources (e.g. reeds for harvesting) and water for human use because of its drier condition. The Pelham wetland was found to be highly invaded by alien vegetation. The study shows that in a rehabilitated wetland and through effective management, ecosystem goods and services do increase. But, due to the high cost associated with the rehabilitation process, the study highlighted the value of assessing the potential benefits of rehabilitating degraded wetlands, particularly ecosystem goods and services that will be secured.
Public participation in wetland rehabilitation with refrence [sic] to long-term management and sustainability : a case study of Hlatikulu and Ntsikeni.
(2007) Nxele, Innocent Zibonele.; Narsiah, Inbersagran.; Kotze, Donovan Charles.
Within wetland rehabilitation projects there has been limited research that focuses on the level and nature of participation by local people, such as individuals from communal areas and landowners from private farms. The overall aim of this study was to analyze the level and nature of participation with specific reference to the holistic long term management and sustainability of wetland rehabilitation projects in Hlatikulu and Ntsikeni, KwaZulu-Natal Province, South Africa. Qualitative and quantitative research methods were employed in this study to examine the level of stakeholder participation in the projects. The Hlatikulu and Ntsikeni projects were undertaken on private land and government land (nature reserve) respectively. The World Overview of Conservation Approaches and Technologies (WOCAT) Framework was applied to analyze the level and nature of participation by different stakeholders that were involved in the selected projects. The study revealed that not all stakeholder groups participated in each and every phase of the projects. In Hlatikulu there was a moderate level of participation from the management of private land, but a limited degree of local participation from the Nsonge community. This, to some extent is attributed to the lack organization in the Nsonge community. There are no structures or authorities through which the process of local participation can be engaged. In Ntsikeni, although the process of continuous local involvement was limited to local Chiefs and some community representatives, the process appeared to be participatory in nature. The selected representatives report back in community meetings and other relevant forums, such as the Ntsikeni Nature Reserve Management Forum, which has been operating successfully for several years. Local people participated in the rehabilitation projects mainly as paid workers, and also in providing advice in the planning processes. For both sites, the results demonstrated that there is a need to enhance and harness active local participation in order to ensure the long term management and sustainability of the Hlatikulu and Ntsikeni wetlands. Within this study, the WOCAT framework was applied to provide insights to two sites, with different land tenure and land use contexts. The results of this study suggest that the WOCAT framework has a high potential to be applied across a diversity wetland rehabilitation sites within South Africa.
Risk, resilience and social-ecological systems in natural resource-based development in South Africa.
(2015) Bowd, Rebecca.; Kotze, Donovan Charles.; Quinn, Nevil Wyndham.
Ecosystem services, which are dependent on ecological and socio-economic variables, can be viewed as having the potential to help alleviate poverty in rural South Africa. These variables do not act in isolation, but rather form a complex adaptive social-ecological system (SES) whereby the ecological and socio-economic aspects interact with each other at multiple spatial and temporal scales. Although ecosystem services frameworks have been developed which balance resource conservation and use according to how society values consumptive and non-consumptive ecosystem services, projects that have successfully achieved both conservation and economic objectives are relatively rare. Part of the reason for this has been attributed to the hiatus between theory and practice, where there is a dearth in decision support systems for guiding the use of ecosystem services as a means of poverty alleviation. Compounding the complexity of SESs in South Africa is the broad socio-political context (e.g. an immature democracy, new policies, new institutions, old legacies, new tenure arrangements, disease and poverty). Development in South Africa is evolving at a rapid rate, and with the potential for detrimental ecological and socio-economic impacts throughout the country if not controlled. The aim of this research is to integrate SES theory into natural resource management practice, so that the concepts of resilience, risk and ecosystem services assessment can be applied effectively in the understanding of natural resource-based enterprises. To achieve this aim, four contexts representing successive development of SES theory are examined, the objectives of which are as follows: i) Integrate ecosystems services evaluation and SES theory to derive a conceptual framework to identify and assess opportunities for natural resource-based economic empowerment at two estuary study sites in the Eastern Cape, South Africa; ii) Apply and adapt the resulting SES conceptual framework to enhance understanding of the resilience of a SES supporting a wetland-based craft enterprise in KwaZulu-Natal, South Africa; iii) Apply and adapt the resulting SES conceptual framework to an EIA setting to evaluate whether such a framework would constitute a useful tool in EIA practice; and iv) Apply and adapt the resulting SES conceptual framework to build understanding of key issues linked to the pellet bioenergy sector in South Africa. This study produced four papers each of which addresses one of the four objectives. For Objective 1, a conceptual ecosystem services framework, with a practical toolkit comprising an ecosystem services inventory and risk assessment, was developed. This work was based on estuarine ecosystem services as it was commissioned as part of the Eastern Cape Estuaries Management Programme. This toolkit was tested at two estuaries in the Eastern Cape (Umngazi and Tyolomnqa), South Africa. For Objective 2, the conceptual framework and associated toolkit developed in Paper 1 was applied and adapted to investigate the threats and opportunities associated with the commercialisation of a natural product-based enterprise (NRBE) located at Mbongolwane, 30km inland of Eshowe, KwaZulu-Natal, South Africa. For Objective 3, the conceptual framework was adapted to develop a systematic framework for EIA practice, which supports and promotes public participation, and which encourages the description, understanding and investigation of the impacts of a proposed development on a receiving SES, in an integrated manner. The framework was applied to two developments: i) a community-based accommodation enterprise at Umngazi estuary; and ii) a proposed wine estate located in the KwaZulu-Natal Midlands. For Objective 4, the resulting conceptual framework was applied and adapted to the woody-biomass industry in South Africa. This industry pelletises wood waste for use as an alternative fuel to coal and gas, and is highly developed throughout the US and Europe. However all four woody-biomass plants which were established in South Africa closed within five years of having been commissioned. The toolkit developed to address objective 4 highlights the threats to establishing and operating a resilient resource-based enterprise which has the potential to contribute to poverty alleviation at a national scale, though job creation and power provision. This thesis is centred on the Anderies et al. (2004) framework for studying the robustness of SESs, and incorporates elements of the Ostrom (2007, 2009) and McGinnis and Ostrom (2014) framework for identifying the social-ecological variables that affect the resilience of a SES. The methods utilised in this study comprise literature reviews, initial development of conceptual frameworks and toolkits using the reviewed literature, the testing of these using stakeholder engagement for a variety of different scenarios, and finally their assessment using published literature and lessons learned through application. Social-ecological system theory was applied in this study to: i) identify potential resilient NRBEs (Paper 1); ii) assess the resilience of selected NRBEs with the view of providing strategies (mitigation measures) to increase the resilience of these enterprises (Papers 1, 2 and 4); iii) assess the resilience of natural resource-based enterprises which have previously been established, and failed (Papers 2 and 4); iv) assess the resilience of proposed natural resource-based enterprises which have not been previously established (Papers 3 and 1); v) assess the resilience of natural resource-based enterprises which are based on ecosystem services (i.e. which do not need to be altered prior to utilisation, are not physically infinite and are unquantifiable) (Papers 1 and 3); and vi) assess the resilience of natural resource-based enterprises which are based on a production process where an ecosystem 'good' is an input, which is processed to form an output which is sold for revenue (Papers 2 and 4). In summary, previous SES conceptual frameworks proved more applicable when used to identify potential natural resource-based enterprises, to assess a proposed enterprise which has yet to be established, and for an enterprise which is based on ecosystem services which do not need to be altered in order to be utilised. The theory proved to be less applicable for assessing an enterprise which has previously been established, and for an enterprise which processes an ecosystem good through a production process. As previous SES theory has focused on analysing the robustness or sustainability of SESs, and is not centred on enterprise dynamics, such as internal business interactions or a production process (as these are not specific to social-ecological interaction), the results are not unexpected. The resulting SES conceptual framework addresses both these shortcomings, as well as the incorporation of ecological component interactions which was also identified as a shortcoming of SES theory when applied to NRBEs. Thus, previous SES theory is more applicable when used at a broad, strategic, long-term level, than at a short-term, operational enterprise level, where internal business dynamics play more of a key role with resilience. Combining SES theory with the concepts of resilience, risk and ecosystem services has proven to be very appropriate for contributing towards natural resource management practices which help alleviate poverty. Furthermore, the study demonstrates how EIA practice could benefit from incorporating SES theory as a way of encouraging the EIA practitioner to co-create a conceptual model of the current and future social-ecological system. This probably constitutes the first attempt to apply and formalise SES constructs to EIA practice within a regulated procedure. Although this study has identified limitations with applying SES theory to assessing the SESs which surround natural resource-based enterprises, SES theory has provided a strong foundation for achieving resilient natural resource-based enterprises which will contribute toward poverty alleviation. This research furthers SES theory in the realm of NRBEs and provides the first ever theoretically-based methodology for selecting, assessing, evaluating and operating resilient NRBEs. The developed conceptual framework and practical contributions have the ability to not only help towards poverty alleviation, but proved applicable to sophisticated entrepreneurial activities for the more affluent. The contributions, both theoretical and practical take into consideration the complex nature of South African SESs, and are applicable to a variety of types and scales of NRBEs. The contributions strongly encourage stakeholder identification, consideration and engagement, and this emphasis contributes towards the balancing of both economic empowerment and sustainable resource use. Although not directly aimed at governmental decision-makers, the contributions show versatility as they have the potential to help inform and guide policy development at a strategic level. By applying SES theory to the development of a conceptual framework specifically for NRBEs, and through the development of practical applications based on the conceptual framework, this research has helped towards addressing the hiatus between theory and practice which has widely been documented.
A system for supporting wetland management decisions.
(1999) Kotze, Donovan Charles.; Breen, Charles Mackie.; Klug, John R.; Hughes, Jeffrey Colin.; O'Connor, Timothy Gordon.
In South Africa, the loss of wetlands and their associated benefits has been considerable. A need was identified for a system that, using available information, would assist in achieving a balance between local, mainly short-term benefits to individuals and spatially wider and longer term benefits to society. Such a system, termed WETLAND-USE, was developed with the philosophy that:(l) wetlands have been well demonstrated to supply several indirect benefits to society (e.g. water quality enhancement); (2) the impact on these benefits can be described on a qualitative basis using field indicators that characterize the wetland and the disturbance associated with a particular land-use; (3) this information can be communicated to wetland users, which will contribute to achieving a desired balance, provided there is an enabling organizational environment and due consideration is taken of the socio-economic and organizational factors affecting wetland management. The primary conceptual framework underlying WETLAND-USE was the pressure-state-perceptions-policy framework, which depicts: the mode of use (i.e. the pressure); how this affects the state of the system (including its underlying processes and the goods and services it delivers); which in turn shape the perceptions that ultimately determine the policy pertaining to further use. This cycle is repeated at a range of organizational levels from local to national and takes place within a particular socioeconomic context. WETLAND-USE, which was designed for use by fieldworkers, and built using a rule-based, expert system approach, has two main parts, dealing largely with biophysical and social aspects respectively. Part 1, which guides the collection of data relating to the state of the wetland, assists in: (1) predicting the likely impacts of disturbances associated with a proposed land-use (the pressure) on the wetland state, and (2) providing ongoing management guidelines for particular land-uses. Part 2 assists in: (1) describing the social, land tenure and policy contexts of the wetland; and (2) establishing and maintaining organizational arrangements, local policy and management objectives and goals. Several discrete investigations were required for the development and refinement of WETLAND-USE, which was done in an iterative fashion. Initial discrete investigations fed into the development of a prototype system which was refined through evaluation using a questionnaire survey and further discrete investigations. The revised system was re-evaluated using a fieldworkshop approach and, based on the performance of the system in the field, it was revised further to produce the final system. In the two initial discrete studies, protocols were developed for characterizing key physical determinants of wetland functioning, notably: (1) degree of wetness, one of the primary functional determinants, described in the field using readily identifiable soil morphological indicators (e.g. matrix chroma and mottles) and (2) landform setting, which strongly influences local flow patterns and lateral exchange of water and water-borne materials. Graminoid plant species composition and functional groups (defined in terms of photosynthetic pathway) were then described in relation to the above physical determinants, together with rainfall, temperature and soil texture, within wetlands spanning a wide altitudinal range. This revealed that degree of wetness and altitude had the strongest influence over the vegetation parameters examined. An investigation into incorporating cumulative impacts into wetland decision making revealed that consideration should be given to: wetland loss in relation to ecoregions and catchments, and the relation of change in wetland extent, spatial configuration and context respectively to wetland function. Current conservation initiatives in KwaZulu-Natal were shown to account poorly for cumulative impacts on wetlands. Rules of thumb for making such considerations, given severe data limitations, were developed with reference to the high turn-over of species along the altitudinal gradient observed in the vegetation study. The "rules" were than applied to a case-study, the upper Mgeni catchment, as part of an initiative to engage a diversity of stakeholders in wetland information gathering and use. This resulted in the selection of priority wetlands in the catchment and an examination of the extent to which integration had been achieved vertically (across hierarchical levels) and horizontally (across organizations within particular hierarchical levels). In order to broaden the range of land-uses accounted for by the WETLAND-USE prototype, it was applied to a communally used wetland, Mbongolwane, and found to account poorly for the traditional cultivation and vegetation harvesting practices encountered. WETLAND-USE was modified to include a greater diversity of land-use types as well as enhancing its capacity to allow assessments to be conducted using the system's general criteria, thereby making WETLAND-USE more robust. In enhancing the capacity of WETLAND-USE to account for the social and organizational dimension of wetland management, the involvement of local and outside organizations in influencing wetland resource use in five sites was examined in relation to predefined frameworks. The sites, Mandlazini wetland, Mbongolwane wetland, Blood River vlei, Ntabamhlope vlei and Wakkerstroom vlei were chosen to represent a diversity of social contexts and management authorities. This revealed that in communally used areas in particular, a wide range of organizations are involved to varying degrees in influencing the use of different wetland resources. The level to which the local organizational environment contributed to sustainable use varied greatly among wetlands, but in all cases had important deficiencies: (1) self-governing resource-management organizations were largely lacking and in communal areas were weakening under contemporary conditions; and (2) although a formal management system was in place in two of the five wetlands, it was largely absent in the remaining three. There has been little involvement from extension services in facilitating local policy development and in promoting alternative land-uses which have less pressure on the state of the wetland. Local wetland management policy and collaboration among land-owners in wetlands under multiple separate ownership such as Blood River vlei was identified as being particularly poor. The evaluations of WETLAND-USE revealed that, in relation to the underlying philosophy of the thesis, WETLAND-USE had been improved through field application and incorporation of the findings of the discrete investigations. Nevertheless, important limitations of the study were highlighted, including: its high level of reliance on expert opinion in the face of a paucity of empirical data relating to the functioning of local wetlands and their attendant benefits (and how these are affected by anthropogenic disturbances), and a particularly shallow representation of socio-economic factors. The identification of these limitations was useful in highlighting key areas for further research.
Towards a macroinvertebrate sampling protocol for monitoring water quality of wetlands in South Africa.
(2005) Bowd, Rebecca.; Quinn, Nevil Wyndham.; Kotze, Donovan Charles.
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.