OpenUCT :: Browsing by Author "Day, Jenny"

Browsing by Author "Day, Jenny"

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Open Access
Are wetland plant communities in the Cape flora influenced by environmental and land-use changes?
(2014) Ramjukadh,Carla-Louise; Day, Jenny; Muasya, Muthama
Considerable attention has been given over the past few years to the distribution and environmental condition of wetlands in South Africa. A 1987-1989 study investigated over one hundred wetlands to establish unique discernible features for grouping and classifying wetlands in the Cape Floristic Region. In the current study, a representative subset of the wetlands surveyed in 1988/89 was re-examined. This thesis characterizes and assesses wetland plant communities and wetland types in both data sets, attempts to identify the major environmental factors influencing plant species distribution in the wetlands, assesses changes in plant species community composition over time; and asks whether surrounding land-use has influenced these. In the current study, of the 142 plants species recorded, 114 were identified to species with 28 to genus level. The historical vegetation data includes 173 plants, of which 115 were identified to species with 58 to genus level.
Open Access
An assessment of the use of nuclear microprobe techniques in pollution studies : quantification of elemental concentrations in fish scales
(2013) Guambe, J F; Day, Jenny; Mars, Johan André
This thesis deals with the applicability of Ion Beam Analysis (IBA) techniques for ascertaining the extent of water pollution by analyzing scales of fish that live in polluted waters. As a fish grows, ions from its immediate environment are incorporated into the matrix of the fish scale and so scales can be used as biomarkers of pollution events.
Open Access
Biodiversity patterns of wetland macroinvertebrate assemblages in the South-Western Cape, South Africa
(2009) Mlambo, Musa; Day, Jenny; Reed, Cecile C
Despite the recent surge in interest in wetland invertebrates, given their immediate importance in overall wetland functioning, these studies have largely been conducted in the northern hemisphere and very little is known in South Africa. In order to fill this knowledge vacuum, this study was conducted to investigate biodiversity patterns of wetland macro invertebrates assemblages in the south-western Cape, South Africa. 140 wetlands were sampled in four geographic clusters, the Cape Flats, the West Coast, the Cederberg and the Agulhas Plain. Open-water, submerged vegetation and emergent vegetation habitats were sampled separately using a square-framed sweep net with a 23.5cm mouth and 80l1m mesh and physico-chemical attributes measured at each site. A total of 126 taxa emanating from more than 26 000 individuals representing 73 genera and 51 families was recorded. Currently, five species new to science were also discovered, three from Hydraenidae (Prosthetops sp. nov, Parhydraena sp. nov and Mesoceration repandum Perkins, 2009), Hydryphantidae (Hydryphanres sp. nov) and Streptocephalidae (Streptocephalus sp. nov). However, all of these new species but one were recorded from single location, suggesting that they might be rare or unique. Richness estimators predicted true taxon richness at about 20-47 taxon more than the observed taxon richness. The high number of uniques and singletons, as well as the Incidence-based Coverage Estimator, suggest that sampling was not adequate to capture the full biodiversity suite. However, I believe this is not necessarily true and this is discussed in detailed in the discussion. The sub-area Cederberg was found to be the biologically richest area, with the three of the new species recorded there. A significant difference was observed in relative abundance (RA) and frequency of occurrence between open-water habitat and vegetated habitats (submerged and emergent vegetation). On the other hand, a significant difference was not found between wetlands with different number of habitat types. No appreciable congruence was seen between different taxonomic groups (i.e. at order and family level) themselves, suggesting that neither can be used as a surrogate for the others. However, predators - which by the way had the highest frequency of occurrence and 2nd highest relative abundance after gatherers - were strongly correlated with overall assemblage and Hemiptera. In addition, together with Hemiptera they had ≥75% similarity with the overall assemblage, suggesting that they are fairly good surrogates for overall assemblage. These results are quite promising especially for biomonitoring programmes and warrant further research. Environmental variables contributed significantly higher in explaining assemblage composition, and the model containing pH, Phosphate, conductivity, turbidity and ammonium was found to explain significant variation in macro invertebrate assemblage.
Open Access
Biological assessment of tropical riverine systems using aquatic macroinvertebrates in Tanzania, East Africa
(2014) Kaaya, Lulu Tunu; Day, Jenny; Dallas, Helen Fiona
In Tanzania, and in East Africa in general, bioassessment methods for monitoring and assessing riverine ecosystems are not yet in place. This thesis describes the development of a macroinvertebrate-based bioassessment method for assessing the degree of anthropogenic disturbance in Tanzanian rivers. The hypotheses that, 'macroinvertebrate assemblages reflect disturbance in river systems'; 'rivers with similar abiotic features have similar macroinvertebrate assemblages'; and 'spatio-temporal variation in macroinvertebrate assemblages influence bioassessment', are tested. Macroinvertebrate and environmental data were collected from the Pangani, Rufiji and Wami-Ruvu basins. Univariate analyses; constrained and un-constrained ordinations and a linear response model were used to test the hypotheses. Five important bioassessment aspects were investigated. A set of 20 criteria for screening reference sites was established and used to identify and distinguish between reference and test sites in the study area. A two-level hierarchical framework for classifying homogenous river types was developed and validated. Three river types were classified: Pangani highland uplands, central eastern Africa uplands and central eastern Africa lowlands, each with two sub-Groups. A macroinvertebrate-based biotic index, the Tanzanian River Scoring System (TARISS), was established for monitoring and assessing anthropogenically induced disturbance in Tanzanian rivers. TARISS has three metrics; number of taxa, TARISS score and average score per taxon (ASPT) for measuring disturbance. Spatio-temporal variations in macroinvertebrate taxa, assemblages and TARISS metrics were examined. Spatial variation within river types was driven by catchment characteristics such as geographical location, geology, altitude and local characteristics such as active channel width, proportions of boulder, cobble and sand on the bottom, influenced reference conditions in all three river types. Temporal variations were significant in the central eastern Africa lowlands, with higher TARISS metrics in wet than in dry periods. Biological and physico-chemical reference conditions were identified for each river type and sub-Group. Guidelines for interpreting TARISS data were established for the validated sub-Groups. In conclusion, TARISS proven to be reliable in detecting anthropogenic disturbance in Tanzanian rivers and is recommended as a national bioassessment method.
Open Access
A comparison of runoff- and spray-drift-related pesticide contamination in agricultural surface waters : exposure, effects and mitigation
(2004) Dabrowski, James Michael; Day, Jenny; Schulz, Ralf
Runoff and spray-drift-related pesticide input are important sources of non pointsource pesticide pollution in surface waters but few studies have directly compared these routes in a risk assessment scenario. Accordingly a risk assessment approach was instituted to determine differences between runoff and spray-drift based on exposure, effect and mitigation. An exposure assessment using predictive modelling that was validated by fieldbased sampling was used to compare relative pesticide inputs associated with runoff and spray-drift at the catchment level.
Open Access
Developing a classification system for Western Cape wetlands
(2002) Jones, M G W; Day, Jenny
Although broad wetland classifications systems are available internationally, a comprehensive wetland classification system, which can be used for both desktop and field analyses, is lacking in South Africa but is required by the South African National Water Act (36 of 1998). Wetlands within the Western Cape were selected from different bioregions and wetland regions. In this project geomorphological characteristics (drainage patterns, landform), hydrological pattern and timing of water availability, were recorded during winter and summer for each studied wetland. Water samples were also collected at the wetlands and analysed for ion and nutrient concentrations and samples of organisms were collected for identification. Multivariate cluster and multidimentional scaling analyses of the chemical and biotic data were used to aid identification of wetland groups. A hierarchical classification system was developed using drainage patterns ( endorheic or exorheic systems) as the primary defining characteristic, followed by wetland landform and hydrological regime as the secondary and tertiary characteristics for identifying wetlands.
Open Access
Distributions of physical habitats and benthic macroinvertebrates in Western Cape headwater streams at multiple spatial and temporal scales
(2005) Schael, Denise Marie; King, Jackie; Day, Jenny; Field, John G
The research in this thesis examines the links between benthic macroinverebrate (invertebrate) distributions and aspects of the physical habitat at different spatial and temporal scales in mountain and foothill zones of rivers in the Western Cape, South Africa. A geomorphological hierarchy was used as the spatial template for studying invertebrate distributions. The different levels of the hierarchy are: catchment, segment, zone, reach, morphological unit and hydraulic biotype. Hydraulic biotypes are visually defined flow and substratum combinations. The hierarchical levels studied in this thesis were catchment, zone, reach and hydraulic biotype.
Open Access
Ecological aspects of the macroinvertebrates associated with two submersed macrophytes in Lake Kariba
(2010) Phiri, Crispen; Day, Jenny
Lagarosiphon ilicifolius Obermeyer and Vallisneria aethiopica Fenzl are the most common and abundant submerged macrophytes in shallow inshore waters of Sanyati Basin, Lake Kariba. Lagarosiphon is structurally more complex than Vallisneria. This study considered the macroinvertebrate assemblages associated with the two plant species with respect to (i) differences in structural complexity, (ii) predator-prey interactions and (iii) water physicochemical conditions.
Open Access
Ecologically relevant low flows for riverine benthic macroinvertebrates: characterization and application
(2010) Tharme, Rebecca Elizabeth; Day, Jenny
Intensifying hydrologic alteration and the resultant degradation of river ecosystems worldwide have catalyzed a growing body of ecohydrological research into the relationships between flow regime attributes, physical habitat dynamics and biotic response, particularly for determining environmental flows. While invertebrate response to floods has received most attention, in this thesis the aim was to identify and characterize low flows that constituted various degrees of physical disturbance to benthic macroinvertebrate assemblages of perennial rivers.
Open Access
The effect of development on seasonal wetlands on the Cape Flats, Western Cape, South Africa
(2004) Govender, Kamal; Meadows, Michael E; Day, Jenny
Seven decades ago, the pre-eminent limnologist, Miss Edith Stephens described the Cape Flats as "a paradise for the aquatic biologist". At that time the area was characterised by numerous temporary or seasonal wetlands that filled and dried in concert with the seasons. Since Miss Stephen's observations, the number of seasonal wetlands on the Cape Flats has dwindled alarmingly and very few remain. This dissertation attempts to account for this and provide guidance for the management of the remaining seasonal wetlands. The dissertation shows how development (characterised by the urban and agricultural land-use) has radically altered the nature of seasonal wetlands and that Typha capensis can be used as an indicator of the ecological value or integrity of these wetlands. Two case studies have been selected to test this premise. The various interrelationships between vegetation, hydrology, nutrients, land-use and ecological value are explored and the proliferation of wetland communities of Typha capensis is shown to be an indicator of negative impacts on seasonal wetlands. The literature review indicates that the proliferation of Typha capensis signifies a decline in habitat diversity and biodiversity (species richness). Typha capensis has been shown to be influenced by streamflow and nutrient input (the plant thrives in shallow areas, permanently inundated with nutrient-rich waters). Therefore, changes to the total area occupied by Typha capensis can be used to illustrate how development has affected the hydrology, habitat diversity, biodiversity and ecological value of seasonal wetlands. The primary source of information was aerial photography, of varying scales, dated from the early 1940s to 2000 and acquired from the Department of Land Affairs: Land Surveys and Mapping. Identifying, mapping and interpreting land-use changes and changes to Typha capensis formed the basis of the research. Water chemistry information, obtained from the Scientific Services Department of the City of Cape Town, and an extensive literature review supplemented the photographic information. Zeekoevlei / Rondevlei wetland and the Khayelitsha wetlands are used as case studies. Together they have been affected by a significant range of impacts generated by different manifestations of development including Wastewater Treatment Works, high-income residential areas, catchment hardening, manipulation of drainage patterns, informal settlement, informal grazing, agricultural runoff and horticultural market gardens. The pattern of land-use change within the selected wetlands' catchments (Lotus River catchment and Kuils River catchment), the impacts of the observed land-use changes, and the impacts to Zeekoevlei / Rondevlei and the Khayelitsha wetlands with respect to seasonality, Typha capensis and ecological value are presented and discussed in detail. In general, urban areas have increased over time to dominate the two catchments. Agricultural areas were consolidated into a few areas while the areas of open space diminished rapidly. Surface and stormwater runoff from "hardened" catchments, irrigation of farmland, and treated effluent from Wastewater Treatment Works all drastically increased, In addition, the concomitant influx of nutrients (nitrates, nitrites and phosphorus) polluted the rivers and wetlands, making them eutrophic and promoting the proliferation of large stands of Typha capensis. The impact of these changes was the loss of seasonality, habitat diversity and biodiversity. Specific recommendations are made for the long term management of Zeekoevlei, Rondevlei and the Khayelitsha wetlands. The proposed management strategy is based on selected management objectives i.e. what is the wetland being managed for? It might not be possible to fully rehabilitate them to a pristine state but management as recreational areas, conservation areas and even educational areas is possible. Key points of the recommended management plans include: * maintaining the winter drawdowns at Zeekoevlei / Rondevlei; * implementation of a dredging and Typha clearing programme; * strategically placed reed beds to purify inflow; * a fire programme for the Khayelitsha wetlands; and * instating an environmental awareness course at the Khayelitsha wetlands. The importance of an Integrated Catchment Management Plan is emphasised. Catchments should be managed as a whole, recognising the relationships between planning, land-use and water resources.
Open Access
Effects of habitat transformation on temporary wetlands in the South-Western Cape, South Africa
(2012) Bird, Matthew S; Day, Jenny
The widespread loss of temporary wetlands to human activities has been well established, but virtually no information exists on how the human transformation of landscapes has altered the ecological character of those wetlands that remain. This thesis investigates environmental conditions and invertebrate assemblages in temporary wetlands in relation to the extent of habitat transformation in the adjacent landscape, using a broad (across multiple landscapes) and a fine (within-landscape) scale of analysis.
Open Access
Effects of water temperature on life history traits of selected South African Aquatic insects: implications for the ecological reserve
(2014) Ross-Gillespie, Vere; Dallas, Helen Fiona; Day, Jenny; Picker, Mike
Life-history studies have informed all areas of aquatic ecological research, whilst also providing information relevant for conservation and management of aquatic systems. Given the large research gap that has existed in this regard for Southern Hemisphere lotic systems, there has been an urgent need to gather such data if effective management policies are to be implemented regionally, especially in the face of ongoing development, anthropogenic impacts, and global climate change. Furthermore, there has been a growing awareness of the need to incorporate thermal guidelines into legislation regarding environmental flows and associated water management plans. In South Africa radical new legislation introduced in 1996 resulted in rivers and aquatic ecosystems being given a right to water of their own- essentially environmental flows, required to protect the aquatic ecosystems associated with the water resource, that are determined separately for all or part of any significant water resource. This water, including both the quantity and quality, is referred to as the "Ecological Reserve." Baseline information on the relationship between temperature and life-history patterns of aquatic insects is required to inform the incorporation of thermal guidelines in the Ecological Reserve determination process. Assuming such information can be gathered, a problem arises as to how the data can be interpreted and incorporated into management guidelines. For instance if representatives of widespread species occurring throughout a country are collected from a single location (say perhaps a single province in South Africa) and then analysed in terms of their thermal limits for growth – would these limits hold true for that same species where it occurs elsewhere? Intra-specific variability, cryptic species and broader phylogenetic constraints all influence the thermal limits of species and need to be considered when examining thermal influences on life-history patterns. This thesis aimed to test the overarching hypothesis that while the life-history traits of aquatic insects could be constrained to some degree by their evolutionary history, they would also be impacted by thermal and hydrological regimes, inducing a degree of plasticity in their life cycles. This hypothesis was tested by examining the key life-history traits of three representative taxa of aquatic insect, namely Lestagella penicillata (Ephemeroptera), Aphanicercella spp. (Plecoptera) and Chimarra ambulans (Trichoptera), and how they are driven by environmental and genetic factors in six rivers situated in the south-western Cape Province of South Africa.
Open Access
Environmental variables and the development of phytoplankton assemblages in a hyper-eutrophic African reservoir
(2007) Mhlanga, Lindah; Day, Jenny
The development of phytoplankton assemblages in relation to environmental variables was investigated in Lake Chivero between 2003 and 2006. The study showed that there has been a decline in dominance of cyanobacteria in Lake Chivero, instead phytoplankton development exhibited two states: (i) a clear state with lesser dominance of Microcystis and proliferation of cryptophytes and chlorophytes (eukaryotic algae) and (ii) a turbid state with domination by Microcystis and gradual exclusion of other species.
Open Access
An evaluation of SASS (South African scoring system) as a tool for the rapid bioassessment of water quality
(1995) Dallas, Helen Fiona; Day, Jenny
The South African Scoring System (SASS) is a rapid bioassessment technique based on one component of riverine biotas, the benthic macroinvertebrates. Each taxon is assigned a tolerance/sensitivity score, which are summed to provide a Total Score. The Average Score per Taxon (ASPT) is calculated by dividing this Total Score by the number of taxa. This study was undertaken to evaluate the SASS technique as a tool for the assessment of water quality. Three study-sites, which differed in water quality, in the south-western Cape were selected for a detailed investigation into sample variability and replication of two methods of biological assessment, namely quantitative box-sampling and SASS. The ability of each method to differentiate between these sites was determined. The more general application of SASS in the south-western Cape was examined at forty nine sites and potential problems associated with SASS, namely biotope availability, temporal variability and longitudinal changes were investigated. A minimum of twelve and four quantitative samples is needed to ensure collection of 95% or 75% of benthic macroinvertebrate taxa respectively. Sampling within a single biotope component, such as a "riffle" or "run" would reduce the number of samples needed. A minimum of four and two SASS samples is needed to ensure collection of 95% or 75% of the taxa respectively. This technique is however designed such that only one sample is taken per site. The Total Score that one sample would produce as a percentage of the Total Score from 20 samples, were 28% , 59% and 45% for Sites 1, 2 and 3 respectively. Total Score increases with increasing sampling effort, whilst ASPT is relatively unaffected by sampling effort. ASPT should therefore be used in interpretation of scores. Variability, as determined by both quantitative sampling and rapid bioassessment, was greatest at the least impacted site. Such sites should be more intensively sampled, either by increasing the number of box- samples taken, or by increasing the time period for SASS sampling.
Open Access
Grazer control on benthic algae in the Berg River, Western Cape, South Africa
(2011) Basic, Dunja; Ewart-Smith, Justine L; Day, Jenny
Benthic environments in streams are areas of high biological activity where primary producers and consumers interact with each other and the environment. Various factors such as light, nutrient availability and temperature affect algal biomass accumulation however disturbance factors and grazing lead to biomass losses as well as changes in the species composition and densities of algae. There are little, if any, studies done on the effects of grazers on benthic algae in South African rivers and as such, this experiment was done in the Berg River, in the Western Cape of South Africa. The aim was to ascertain the effects of herbivores on benthic algae within the river and lit was hypothesized that periphyton biomass would be higher where grazer densities were lower and that the differences observed in biomass of periphyton between treatments would increase over time. It was also hypothesized that there would be a lower diversity of algae where there were lower herbivore densities. A randomized block design experiment was set up in the Berg River and treatments of 'excluded herbivores' and 'included herbivores' were set up, with two pairs of each treatment spread across four replicates. Stones from the stream were randomly selected and placed in the boxes. After five days half of the boxes were sampled and after eight days, the remaining half was sampled. Stones were scrubbed to remove periphyton from the stones and a sub-sample of 50ml was removed from each for later algal species identification. Invertebrates were removed from the boxes, preserved in ethanol and later identified to family level. Chl-a and AEDW (mg/m²) were determined from the samples as were invertebrate and algal densities. The results showed that there were no herbivore density effects on biomass most likely due to the season of sampling and the length of the experiment. However, the effect on algal densities was more pronounced as there was a higher variety of algal forms present where herbivore densities were lower. To get a better idea of how herbivores affect periphyton other factors need to be taken into account like experimental time period, season and different environmental conditions.
Open Access
The impact of alien invasive smallmouth bass (Micropterus dolomieu) on the indigenous fish of the Rondegat River : a quantitative assessment with implications for rehabilitation
(2005) Woodford, Darragh J; Day, Jenny; Impson, Dean; Bills, Roger
Alien invasive fishes are a growing concern in inland water ecosystems around the world, as they are capable of causing serious damage, especially to indigenous fish populations. Mechanisms include direct predation on indigenous fish by alien predatory species, competition for food and space between native and introduced species, the introduction of alien parasites and pathogens, and general environmental degradation. The Cape Floristic Region (CFR) of South Africa, which is defined by a unique and highly diverse floral kingdom, is also home to a unique and highly threatened ichthyofauna. This ichthyofauna consists of relatively few species, but exhibits the highest proportion of endemicity in the country. Threats to fishes include habitat destruction through bulldozing and water extraction, water quality degradation, restriction of migration by dams and weirs, and alien invasive fishes. The North American smallmouth bass (Micropterus dolomieu Lacepede) has long been regarded by nature conservators as the most threatening invasive species, and much anecdotal and survey data suggests that this species has had a major role in the depletion and extirpation of indigenous fish populations throughout the CFR. However, no study has ever properly quantified this impact relative to other potential threats that could have precipitated the perceived indigenous fish losses. This is a problem, as it makes the implementation of active control measures difficult to justify to a sceptical public and potential sponsors. The Rondegat River is a tributary of the Olifants River, which rises in the Cedarberg Mountains and flows into the Clanwilliam Dam reservoir. It is partially invaded by M dolomieu, which have penetrated the lower quarter of the river up to a waterfall barrier. This river is home to five species of indigenous fish, including the Clanwilliam yellowfish (Labeobarbus capensis Smith), Clanwilliam redfin (Barbus calidus Barnard), fiery redfin (Pseudobarbus phlegethon Barnard), Clanwilliam rock catfish (Austroglanis gilli Barnard) and the Cape galaxiid (Galaxias zebratus Castelnau). This project was designed to quantify the impact of M dolomieu on these species relative to the alternate potential impacts of physical habitat degradation from agriculture and alien invasive riparian trees, and of food availability. Seasonal surveys were conducted at eight sites on the river in September, October and November 2003, and in April 2004. Four sets of riffles and pools were selected upstream of the waterfall barrier, and four below. Quantitative electrofishing was used to survey fish in riffles, while snorkelling surveys were conducted in pools. All fish species were also caught with seine and tyke nets for dietary analyses. Physical habitat variables were measured at each site, and used to assess changing habitat quality between the sites. Invertebrate samples were also taken along with visual abundance estimations of other food types, to gauge food availability. Fish surveys revealed the loss of B. calidus, P. phlegethon, A. gilli and G. zebratus at bass-invaded sites. Galaxias zebratus was only found in the upper reaches of the river, and so was possibly never common in the lower river. Labeobarbus capensis, while still below the waterfall, appeared to be suffering from near-total loss of post spawning recruits. Discriminant function analyses revealed sedimentation to be a key factor of habitat degradation that characterized invaded sites. However, linear regressions between habitat variables and indigenous fish densities indicated sedimentation to not be a significant negative influence on indigenous fish distributions. Although sedimentation did not appear to influence A. gilli densities at non-invaded sites, it is highly likely that it increased the vulnerability of this species to M dolomieu in the lower river, by removing benthic cover used to avoid predation. In the case of all species, food availability did not seem an important factor in dictating fish distributions. Consequently, predation by M dolomieu was confirmed as the critical mechanism behind the loss of B. calidus, P. phlegethon, A.gilli and juvenile L. capensis in the lower river. A rehabilitation plan is proposed for the Rondegat River. Central to this plan is the formation of a conservancy between the land-owners of the catchment and the custodians of the Cedarberg Wilderness Area. The most effective strategy will be to eradicate M dolomieu from the lower river with piscicides, while at the same time taking steps to rehabilitate the riparian zone throughout the river. A holistic rehabilitation programme such as this would provide an excellent model for future rehabilitation efforts within the CFR.
Open Access
Impacts of non-native rainbow trout on stream food webs in the Cape Floristic Region, South Africa integrating evidence from surveys and experiments
(2013) Shelton, Jeremy Mark; Day, Jenny; Samways, Michael
Impacts of invasive predators may be influenced by whether or not native predators which function in the same way as the invasive predator exist in the recipient system. Impacts are expected to be strong in isolated systems lacking functionally similar predators because native species will be naïve to the foraging behaviour of the introduced predator, and because the invasion is likely to change the role which the native predator assemblage performs. In this thesis I studied how the introduction of a functionally novel predatory fish, rainbow trout Oncorhynchus mykiss, has affected native fish, and how changes in the functioning of the predator assemblage have influenced lower trophic levels, in headwater streams in a catchment area within the Cape Floristic Region, South Africa. Fish populations, benthic invertebrate assemblages, benthic algae and particulate organic matter were surveyed in each of 24 minimally-disturbed headwater streams in the upper Breede River catchment, and relevant environmental variables in each stream measured, over one summer.
Open Access
The implications of fynbos phytogeography for wetland photoassessment
(2011) Corry, Fynn; Day, Jenny; Muasya, Muthama; Sieben, Erwin
The initial focus of the present study was intended to develop phyto-assessment tools for the evaluation of the environmental condition of lowland wetlands in the Fynbos biome of the South Western Cape of South Africa. A field survey and analysis of freshwater wetland vegetation across the Cape coastal lowlands (below 200m a.s.l.) was undertaken in the present study to explore the potential to identify aspects of the vegetation that could serve as indicators of the present environmental state within wetlands. The Braun Blanquet approach was employed for the vegetation sampling of 59 wetlands in three subregions of the coastal lowlands of the Fynbos biome.
Open Access
An integrated planning approach for the conservation of freshwater ecosystems in South Africa
(2009) Amis, Mao Angua.; Day, Jenny; Rouget, Mathieu
Freshwater ecosystems underpin the fabric of society and the environment, providing essential ecosystem services such as water and food, upon which all human beings depend. In order to secure these vital services requires the sustainable management of freshwater ecosystems. At present however, freshwater biodiversity is under severe threat from anthropogenic disturbances, and the situation is expected to worsen due to population growth and global change. Coupled with the threats to freshwater biota are the limited resources available to secure their protection. There is a need to therefore prioritise freshwater ecosystems in a comprehensive, adequate and representative manner to maximise the outcomes of conservation effort. The concept of systematic conservation planning was developed to address this challenge. It offers a suitable framework for achieving conservation goals in the face of other competing land uses. The principles of systematic conservation planning are being widely applied in terrestrial and marine ecosystems, but their application in freshwater ecosystems is still relatively limited. Freshwater ecosystems provide challenges to conservation planning that are unique from those of terrestrial and marine ecosystems, such as the longitudinal nature of river systems and the associated connectivity, and catchment divides that constrain some obligate species. As a result freshwater ecosystems require conservation planning tools and approaches that are specifically geared towards addressing these unique challenges. Progress has recently been achieved in addressing some of these challenges, but there are still other outstanding issues that have not been comprehensively addressed. The aim of this thesis was to develop new frameworks, and test approaches for the application of systematic conservation planning principles in the conservation of freshwater ecosystems in South Africa. The thesis addressed a range of issues along the systematic conservation planning continuum from biodiversity assessment to implementation. I first carried out a focused review of systematic conservation literature between 1987- 2006, to gauge the extent to which freshwater ecosystems have being integrated in conservation assessments. Most of the focus was found to be on terrestrial ecosystems with minimal incorporation of freshwater biodiversity. Wetlands for example, were in most cases incorporated into conservation assessments without taking their diversity into account. This was partly attributed to the difficulty of classifying wetlands. I therefore developed and tested a hierarchical GIS framework for automating wetland classification as a strategy for incorporating wetland biodiversity, functions and benefits into broad scale conservation planning.
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Integrating freshwater and terrestrial priorities in conservation planning
(2009) Amis, Mao A; Rouget, Mathieu; Lotter, Mervyn; Day, Jenny
The integration of freshwater and terrestrial biodiversity priorities in systematic conservation planning is a major challenge to conservation planners. Maintaining upstream–downstream connectivity and the influence of catchments on freshwater ecological integrity are some of the issues that make it difficult to reconcile terrestrial and freshwater conservation planning. As a result most conservation assessments are often biased towards terrestrial systems without adequate incorporation of freshwater biodiversity in determining priority areas for conservation. In this paper, we propose a protocol for integrating the assessment of freshwater and terrestrial priorities in conservation planning, based on a case study from Mpumalanga Province in South Africa. The approach involves the separate assessment of freshwater priority areas, and using the outcome to influence the selection of terrestrial priority areas. This allowed both freshwater and terrestrial biodiversity to be incorporated in conservation planning without compromising their unique requirements. To test the effectiveness of this approach, we assessed percentage overlap between freshwater and terrestrial priority areas, target achievement, and the area required to achieve targets. We then compared the outcome from the proposed approach with the separate assessments of freshwater and terrestrial biodiversity priorities, and when both systems are given an equal weighting in a single assessment. The results showed that there was a noticeable improvement in the overlap of priority areas for freshwater and terrestrial biodiversity from 23% to 47%. Target achievement for freshwater biodiversity improved by 10% when terrestrial assessment was based on freshwater priority areas as opposed to terrestrial systems being assessed alone. There was negligible increase in area required, whether there was integration of freshwater and terrestrial biodiversity or no integration. We conclude that the most efficient way to achieve integration in conservation planning is to preferentially select areas where freshwater and terrestrial biodiversity priorities overlap.