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. / Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1999.

Phylogeographic patterns of coastal organisms with different life histories and breeding strategies may reveal patterns not consistent with the current delineation of the biogeographic provinces around South Africa. The subdivision of the South African coastline into these three main climatological or biogeographic regions: namely the cool temperate west coast, the warm temperate south coast and the subtropical east coast, is based on average seawater temperatures and hydrological conditions. Genealogies of two estuarine fish species Atherina breviceps, a marine breeder, and Gilchristella aestuaria, an estuarine spawner, were reconstructed using mitochondrial DNA (mtDNA) control region sequences. The study comprised two components, an assessment of a small dataset of both fish species to compare their population structure along the South African coastline and a more comprehensive investigation of the phylogeography of G. aestuaria collected from 21 estuaries around the coast. The comparative study of A. breviceps and G. aestuaria indicate different population distribution patterns along the South African coastline. Results of the A. breviceps analysis demonstrate substantial gene flow due to the random mixing of alleles, while the comparative G. aestuaria dataset indicates a more structured population and considerably less gene flow. The G. aestuaria population demonstrates geographic separation into four groups, namely the west coast (Great Berg), Bot (south coast), Seekoei (south coast) and east coast (Bushmans, Kasouga and Cefane). Results from the larger G. aestuaria dataset indicate that the phylogeographic patterns observed during this study do not conform to existing biogeographic boundaries along the southern African coastline. The delineation identified during this study between the warm temperate and subtropical regions is further south than originally perceived and this southward extension can be ascribed to the prevailing hydrology. The life history patterns and ecology of these two estuarine fish species appears key to understanding their population structure. These factors interact with environmental characteristics such as physical oceanography and the distribution of estuaries (along the coastline) to explain the observed distribution patterns and population structure of A. breviceps and G. aestuaria.

During 1982 benthic and floating filamentous algal mats appeared in the maturation ponds of the Grahamstown Sewage Disposal Works. These mats clogged the ponds and reduced the efficiency by which the effluent was purified. As they continued to be a problem despite numerous efforts to remove them, this study was initiated to investigate the alga, establish why it was successful in the pond environment, and how its growth could be controlled. The physico-chemical environment of a representative maturation pond was characterised while laboratory studies were conducted to investigate the growth, photosynthetic and respiratory characteristics in the alga. The alga was identified as Rhizoclonium riparium (Roth) Harv. although its morphological variability was greater than that reported in the literature. Growth and photosynthetic studies indicated that the alga favoured temperatures between 20 and 30⁰C and relatively high light intensity (700μE.m⁻².s⁻¹) and that it was highly productive. In addition, the alga exhibited photoadaptive ability, although it seemed to be sensitive to photoinhibition. Its success in the maturation pond was attributed to the favourable physico-chemical environment, particularly the high transparency of the effluent which allowed the penetration of PAR to the pond floor and to the alga's ability to adapt to the change in environment when it floated from the pond floor to its surface. Although the algal mats contribute to the oxidation of the effuent within the maturation pond, they are generally detrimental to the system because they shade the water column and inhibit wind-induced mixing. Recommendations on methods of controlling of the mats are presented. / KMBT_363 / Adobe Acrobat 9.53 Paper Capture Plug-in

Tidal exchanges of organic carbon, nitrogen and phosphorus between a south temperate Sarcocornia marsh and its associated estuary are examined. Subterranean water flow was small, and the hydraulic exchange between the two systems largely surficial. The dominant tidal signal was semi-diurnal, and the extent of inundation of the marsh varied considerably as a consequence of interactions of semi-lunar tidal cycles with changes in daily mean sea level. Annual net fluxes of organic carbon were directed from the marsh to the estuary, but amounted to less than 2% of marsh aerial net primary productivity. This indicates the incompatibility of E.P. Odum's outwelling hypothesis to this marsh-estuarine system. The direction of net flux of organic carbon switched on a time-scale of days. These directions were largely correlated with mesoscale oceanic events, which materially altered the extent of marsh inundation, and which provided evidence of the mutual exclusivity of outwelling of DOC from the marsh and oceanic upwelling. Laboratory mesocosm experiments using intact marsh blocks of sediment from the marsh were conducted to identify the proximate processes and interactions at the marsh-water interface responsible for the variability of marsh-estuarine exchanges. Patterns of fluxes of organic carbon, total nitrogen and phosphorus were markedly different in the structurally contrasted tidal creek and Sarcocornia Zone regions of the marsh. Both regions exported these components, but the fluxes of organic carbon and total phosphorus were significantly larger from the tidal creek than from the Sarcocornia zone, and the opposite applied to nitrogen. The presence of brachyuran crabs . the most numerous macrofauna on the marsh enhanced the flux of carbon, nitrogen and phosphorus from the marsh biocoenosis, largely as a result of the effect of their bioturbation. Evidence is examined which suggests that differential mobilization of nutrients in the two zones by crabs is responsible for biogeochemical coupling of these two regions , which may account for the elevated productivity of salt- marsh systems

This thesis develops a technique for the identification, classification and quantification of instream flow environments. These features have been traditionally referred to as 'habitats' by lotic ecologists, in this research they are termed 'hydraulic biotopes'. The hydraulic biotope is the lowest of six nested levels of a hierarchical geomorphological model. This model has been developed as a tool to assist river managers, researchers and conservationists to categorise or classify rivers with respect to their geomorphic characteristics. Each level of the model provides data at a different level of resolution. This ranges from the broad scale catchment data to the site specific 'habitat' or hydraulic biotope data. Although this thesis is primarily concerned with the development of the hydraulic biotope, the interaction of all catchment variables needs to be recognised. Detailed analysis of hydraulic biotope data in the Buffalo River are presented within the broader hierarchical model. Consultation with lotic ecologists, together with a review of ecological literature, emphasised the need for a standardised terminology for the classification of ecologically significant instream flow environments. At present a fairly haphazard 'habitat' classification tends to be carried out by most researchers, this often leads to confusion in the identification and naming of different hydraulic biotopes ('habitats'). This confusion is exaggerated by the sharing of terminology between lotic ecology and fluvial geomorphology, usually for the categorisation of different types of features. A review of the ecological literature emphasises the importance of flow hydraulics within a river to describe the distribution of biota. The hydraulic variables considered to be most significant include velocity and depth. As river morphology directly determines the prevailing distribution of depth, velocity and substratum, it is obvious that there are important links to be made between fluvial geomorphology and lotic ecology. This thesis explores the potential of the hydraulic biotope as a tool to help develop those links. This thesis presents a standardised classification matrix for the identification of hydraulic biotopes. The matrix is simply based on water surface characteristics together with channel bed substratum. The validity of this matrix is tested by statistical analysis of hydraulic variables quantifying flow conditions within the various hydraulic biotope classes. Data is presented from four different river systems, each representing a different sedimentological environment. Where possible the influence of discharge has been considered. Results from more than 3000 data points show that hydraulic biotopes have distinct hydraulic characteristics in terms of velocity-depth ratio, Froude number, Reynolds number, 'roughness' Reynolds number and shear velocity. These hydraulic indices represent flow conditions both as an average within the water column, and near the bed. Statistical analysis shows that the hydraulic characteristics of the various hydraulic biotope classes are relatively consistent both within different fluvial environments and at different stages of flow. Unlike the morphological unit in which the hydraulic biotope is nested, in stream flow environments are shown to be temporally dynamic. Using the classification matrix as a tool for identification, hydraulic biotopes identified at one discharge are shown to be transformed from one class to another as a response to change in stage. The pattern of transformation is shown to be consistent within different sedimentological environments. An examination of the associations between hydraulic biotopes and morphological units demonstrates that, although some hydraulic biotopes are common to all morphological units (backwater pools, pools and runs), some features have specific associations. In this study rapids were found to be prevalent in bedrock pavement, bedrock pool and plane bed morphology, while cascades, chutes and riffles were common to plane bed, step and riffle morphology. Results from this research indicate that the hydraulic biotope, within the hierarchical geomorphological model, has the potential to aid the prediction of channel adjustment and associated 'habitat' (hydraulic biotope) transformation in response to changes in flow and sediment yield. These are likely to become increasingly important issues as South Africa strives to maintain a balance between the development of water resources to meet the needs of the rapidly expanding population, whilst at the same time maintaining the fluvial environment for sustainable use.

Palmiet peatlands in the agricultural landscape are viewed by farmers as problematic. They obstruct the effective passage of water along watercourses and therefore promote localized flooding of lands and infrastructure, and they trap sediment delivered along watercourses that drowns fields and infrastructure with sedimentary deposits. These events are problematic for farmers trying to make a living off the land. Wetlands are also often viewed as wastelands that should be put to more productive use. The obvious thing to do is to bring in machinery to drain the wetlands and improve the flow of water and sediment through these wetlands.

Ectomycorrhizal (ECM) associations are important elements of forest biomes, connecting and transferring nutrients through an intricate and complex system of hyphal networks, ensuring plants of the nutrients they require, in nutrient poor soil. ECM research and particularly investigations into the diversity of the fungal partners has not received much attention in South Africa, hindering the advance of research in this field. This has been attributed to the difficulty of identifying the mycobionts involved in the symbiosis. The objectives of this study were to examine the ECM fungal diversity associating with Pinus patula, in selected forest plantations in Mpumalanga, South Africa. Both morphological and molecular techniques were used to identify specimens of both sporocarp collections and ECM root tip morphotypes. Morphological analysis of the ECM root tips involved characterisation of root morphology such as colour, branching and texture, and anatomical analysis examined hyphal arrangement in the root mantle and rhizomorphs. Molecular analysis involved sequencing of the Internal Transcribed Spacer (ITS) region and comparative BLAST analysis. Twenty-four sporocarp species were identified from 13 genera, namely: Amanita, Boletus, Clavulina, Inocybe, Lactarius, Rhizopogon, Russula, Scleroderma, Suillus, Tricholoma, Thelephora, Tomentella and Xerocomus. ECM root tip analysis led to the characterisation of 7 wild-type morphotypes identified as an Albatrellus sp., 2 Amanita species, a Rhizopogon sp., Thelephora terrestris, a Tomentella sp. and Scleroderma citrinum. A secondary objective was to determine whether fertilisation treatments within the study sites were responsible for differences in fungal species community structure. No evidence of a change in species diversity or shift in species composition was encountered. It is envisaged that these comprehensive ECM descriptions will be used as reference material to stimulate continued research in this field in South Africa.

Ph.D. / The investigations reported here conducted during 1990-1994 had the following objectives: Selection of representative localities in impoundments and rivers in wetlands affected by radionuclide- and metal-containing effluents and seepage water from mines and metal-processing industries. To determine the occurrence and concentration of radionuclides and selected metals in mine- and industry-polluted waters and sediments in catchments of the Blesbokspruit, the Klip River and the Crocodile River systems. To establish radionuclide and metal concentrations in some semi-aquatic and aquatic weeds in these mine- and industry-polluted waters with observations on the ability of some plants to accumulate certain metals in their roots and/or shoots. To evaluate some benthic macro-invertebrate organisms as possible indicators of radionuclide and metal pollution in the affected streams. To determine the radionuclide and metal concentrations in selected vegetable crops irrigated with mine- and industry-polluted water. The localities where the investigation took place were mainly in wetland regions on the East and West Rand. Water of polluted streams traverse expansive wetlands containing floating, emergent and submerged aquatic vegetation. These plants play an important role in the recovery from pollution of the affected waters. Pollutants are also available to and accumulated by other aquatic organisms such as crabs, fish and birds. In addition, the same water is often used for the irrigation of vegetable crops, thereby creating potential pathways through which these pollutants may be consumed by humans. All the above objectives have largely been met in as such that potential sources of pollution were identified and pollutants detected in the abiotic (water and sediments) environment. These pollutants were also found in wetland biota as well as agricultural crops irrigated with contaminated water. Potential pathways for the transfer of these pollutants were identified and dose assessment modelling was conducted.

Ferreira, M., Dr.; Van Vuren, J.H.J., Prof. / The Wilge River is one of many adjoining tributaries of the Olifants River located in the Olifants Water Management Area (WMA4) within the Highveld (11) – Lower Level 1 Ecoregion (Dallas, 2007). These river systems experience extreme demand for natural resources, as they flow through heavily utilised economic hubs. They are closely associated with land modification and pollution, primarily mining and industrial-related disturbances and extensive agricultural activities, all of which are the primary cause of impairment to river health. The primary aim of this study was to study the aquatic macroinvertebrate communities at six monitoring sites along the Wilge River, coupled with two monitoring sites on adjoining tributaries, and to further identify the driving variables that influence these communities both spatially and temporally. Functional Feeding Groups (FFGs) of the aquatic macroinvertebrates and the surrounding land use in the project area was taken into account. The analysis of in situ water quality measured during the period March 2010 to May 2013, clearly illustrated high levels of variation both spatially and temporally. In situ water quality was a limiting factor to the aquatic ecosystem from a Dissolved Oxygen (DO) and Percentage Saturation (DO%) perspective. The remaining parameters were within the South African guideline for aquatic ecosystems (DWAF, 1996). Habitat availability illustrated clear seasonal variation as well, of which the wet season indicated better habitat availability compared to the dry season. The dominant biotopes in the study area were vegetation (VEG) and gravel, sand and mud (GSM). Site WIL04 illustrated the poorest habitat integrity overall primarily attributed to the site’s steep incised banks and deep channel which lacks the stones biotope. The South African Scoring System, Version 5 (SASS5) results indicated that there was a change in the integrity of the aquatic macroinvertebrate community’s in the study area and further illustrated variability both spatially and temporally. It was evident that the aquatic macroinvertebrate communities within the Wilge River and two adjoining tributaries sampled, were generally in a slightly to modified state with moderate variations. The lowest number of taxa, SASS5 and average score per taxon (ASPT) values was recorded at site WIL04 and this was mainly brought about due to changes in flow and habitat availability. The ASPT score ranged from 3.8 at site WIL04 to 7.7 at site WIL02, indicating that the aquatic macroinvertebrate communities were primarily composed of tolerant and moderately tolerant taxa. Of these mostly tolerant taxa, predators and gathering collector populations were the most dominant FFG, with the shredders being the least abundant within the study area. The Bray-Curtis cluster analysis of the aquatic macroinvertebrate communities clearly illustrated a high level of similarity and seasonal variation among the communities. The high similarity was an indication that similar taxa occurred at the sites within the groups identified. However, in accordance with the Similarity Percentages (SIMPER) analysis, there was no clear indication of dominant taxa. There was however a separation of sites TRI01 and WIL04. This was expected due to differences in the physical stream condition (flow) and other habitats / general biotopes, primarily at site WIL04. Stream bed composition is one of the most important physical factors controlling the structure of freshwater invertebrate communities (Mackay and Eastburn, 1990). The separation and similarity of these two sites were not a consequence of dominant taxa, but rather a consequence of differing water quality, habitat availability and common tolerant taxa driving the system. Inclusive, the seasonal variation illustrated was contributing to the changes in the in situ water quality and habitat availability, thus making seasonal variation also a driving variable, in the differences between the sites. The Redundancy Analysis (RDA) bi-plots indicated, as with the Bray-Curtis similarity matrices and related NMDS plot, that there was a distinct seasonal separation. It further illustrated a clear separation of site TRI01 and WIL04 due to reasons mentioned above. All the environmental variables, with the exception of pH, was identified as significant drivers in the river systems (p<0.05). This however varied seasonally. During the wet season, clarity, DO and pH were the significant drivers, while clarity, TDS/EC, percentage saturation and pH were the significant drivers during the dry season (p<0.05). These drivers were expected due to possible sources namely intensive agriculture in the project area. The RDA tri-plots further indicated the significant role that the ASPT, SASS5 score and the IHAS played within the aquatic macroinvertebrate community (p<0.05). This confirms the importance of habitat as a driving variable in aquatic macroinvertebrate community structures. Consequently, the driving variables in the separation of the sites along the Wilge River and two adjoining tributaries, appear to be a combination of variables (DO, percentage saturation, TDS/EC, clarity and pH), including habitat availability (based on IHAS scores). To determine the effects and relations between the primary driving changes, to the surrounding land uses in the project area, further multivariate analyses were conducted, which included the FFGs. It was clearly indicated that predators have a negative correlation with the rest of the FFG’s which was expected. As the percentage of predators increase at a site, the percentage of the other FFG’s decreased. Therefore, there was a large variation and clear changes in the food sources constantly entering into the river system. This is normally related to changes in the land use.

This report on the diatoms (Bacillariophyta) of the Sundays and Great Fish rivers is divided into two sections. In Volume 1 the taxonomy of the diatoms from these two river systems is examined. A total of 331 taxa were studied, of which 5 are described as new species. Two taxa are given new names, since they were previously known under later homonyms. Twenty seven taxa were recorded for the first time from South Africa, while a number of species are given amended descriptions in the light of fresh information obtained concerning them. A few taxa (chiefly South African forms) have been united with previously described taxa. For the remainder of the taxa mentioned in the text, comments are passed with regard to their taxonomy and dimensions, based on facts gained through literature surveys and personal observations of the relevant taxa. As far as possible all taxa examined in Volume 1 are illustrated, and these illustrations are presented in Volume 3 of this study. Volume 2 deals with the ecology of the diatoms in the Sundays River. Special emphasis is laid on relating the composition of the diatom associations at the selected stations to the ambient salinity and ionic composition of the water. A new index, the Salinity Tolerance Index (STI), is proposed to summarize by means of a numerical value the information obtained from the analysis of a diatom association with respect to the character of the component taxa, and to indicate whether the association is derived from a freshwater, brackish water or marine source. The efficacy of the STI is evaluated in the text. The effect of the geological formations of the Sundays River valley and the underground waters emanating from them is discussed in the text. The consequences of a severe drought in the lower Sundays River, including hypersaline water in the upper estuary, on the diatom flora are also investigated.