Philosophiae Doctor - PhD (Biodiversity and Conservation Biology)

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An analysis of primary and secondary production in lake Kariba in a changing climate
(University of Western Cape, 2011) Ndebele-Murisa, Mzime R.; Musil, Charles; Raitt, Lincoln
Analysis of temperature, rainfall and evaporation records over a 44-year period spanning the years 1964 to 2008 indicates changes in the climate around Lake Kariba. Mean annual temperatures have increased by approximately 1.5oC, and pan evaporation rates by about 25%, with rainfall having declined by an average of 27.1 mm since 1964 at an average rate of 6.3 mm per decade. At the same time, lake water temperatures, evaporation rates, and water loss from the lake have increased, which have adversely affected lake water levels, nutrient and thermal dynamics. The most prominent influence of the changing climate on Lake Kariba has been a reduction in the lake water levels, averaging 9.5 m over the past two decades. These are associated with increased warming, reduced rainfall and diminished water and therefore nutrient inflow into the lake. The warmer climate has increased temperatures in the upper layers of lake water, the epilimnion, by an overall average of 1.9°C between 1965 and 2009. The warmer epilimnion has led to a more stable thermocline in the lake, and its upward migration from a previously reported 20 m depth to the current 2 to 5 m depth reported in the lake’s Sanyati Basin. A consequence of the more stable thermocline has been the trapping of greater amounts of nutrients in the deep, cold bottom waters of the lake, the hypolimnion, and this coupled with a shorter mixing (turnover) period is leading to reduced nutrient availability within the epilimnion. This is evident from a measured 50% reduction in nitrogen levels within the epilimnion, with phosphorus levels displaying a much smaller net decline due to localised sources of pollution inflows into the lake. These changes in lake thermal dynamics and density stratification have reduced the volume of the lake epilimnion by ~50%, which includes the well mixed, oxygenated euphotic zone leading to more acidic waters (lower pH) and increased water ionic concentrations (conductivity), and decreased dissolved oxygen levels, which have resulted in a 95% reduction in phytoplankton biomass and a 57% decline in primary production rates since the 1980s. The reduced nitrogen levels especially have contributed to a proliferation of nitrogen-fixing Cyanophyceae, the dominant Cylindrospermopsis raciborskii comprising up to 66% of the total phytoplankton biomass and 45.6% of the measured total phytoplankton cellular concentrations. Also, shifts in seasonal dominance of different phytoplankton groups have been observed in the lake during turnover, the Cyanophyceae having increased in dominance from 60% of the total phytoplankton biomass in the early 1980’s to the current 75%. In contrast, the Bacillariophyceae have declined substantially, from 18% of the total phytoplankton biomass in the early 1980’s to the current 1.7%. The diminished phytoplankton biomass of more palatable phytoplankton, and the proliferation of smaller, less palatable phytoplankton taxa, has resulted in reduced zooplankton biomass and species richness and altered zooplankton species composition. Concentrations of large Cladocera and Copepoda especially have declined substantially in the lake by up to 93.3% since the mid 1970s, with small Rotifera currently comprising 64% of the total zooplankton biomass. The reductions in zooplankton biomass correspond with recorded decreases in catches per unit effort for the sardine Limnothrissa miodon (Kapenta), which have been steadily declining in the lake since 1986.
Assisted flocculation of Chlorella Sorokiniana by co-culture with filamentous fungi
(University of the Western Cape, 2015) Mackay, Stephen; Bauer, R.
Biofuel production from microalgae is currently not economically competitive with fossil fuels due to high operational costs. A sustainable system needs to be developed which considers cultivation, harvesting and conversion to fuels as a single loop. The harvesting step has been identified as a major bottleneck within the biofuel production process, contributing to a significant proportion of the operational cost (20-30%). Chemical flocculation is a more affordable alternative to centrifugation and filtration. Chemical flocculants however negatively impact the quality of biomass and conversion efficiency to biofuel by increasing biomass ash content. Bioflocculation with biopolymers or microbes have a minimal impact on the quality of biomass. In this study, the interaction between the filamentous fungus Isaria fumosorosea and the microalgae C. sorokiniana is investigated. Under strict autotrophic conditions at pH 7-8, co-culture of microalgae (2-20 μm) with fungal blastospores resulted in theidevelopment of large pellets (1-2 mm) which may be easily harvested by sedimentation or filtration at 95% harvesting efficiency. Fungal assisted bioflocculation was compared to other harvesting methods with respect to cost and impact on the hydrothermal conversion process. Low cost carbon sources, including waste hydrothermal nutrients, minimal sugar concentrations and algal exudate may reduce fungal cultivation costs. Waste products, such as organic carbon, N, P, CO₂ and trace metals can be recycled and used for algae and fungal cultivation, closing the loop to make the system sustainable.
Autecology of the rhombic egg-eater, Dasypeltis scabra
(University of the Western Cape, 2022) Barends, Jody Michael; Maritz, Bryan
Efforts to prevent global losses of biodiversity are hindered by incomplete knowledge of the functional importance of species. In part, this is due to a paucity of information on the basic biology of most species resulting in a poor understanding of their ecological roles. Snakes represent a speciose group of carnivorous predators that are likely important ecological components of a variety of environments given their roles in modulating the sizes of the populations of their prey. Unfortunately, the ecological importance of most species of snakes has yet to be empirically demonstrated, particularly in native systems.
Biochemical investigation of anti-cancer activity of Tulbaghia violacea
(UWC, 2012) Saibu, Gbemisola Morounke; Meyer, Mervin; Katerere, David
Natural products have been a source of many pharmaceutical drugs and a number of drugs that are currently used in the treatment of cancer are derivatives of compounds originally isolated from natural products. There is evidence that extracts of Tulbaghia violacea can be used to treat cancer. The activation of apoptosis in cancer cells is a target for the development of novel anti-cancer drugs since one of the characteristics of cancer cells is resistance to apoptosis due to the deregulation of biochemical pathways leading to apoptosis. In fact, many current anti-cancer drugs exert their effects through the activation of apoptosis. Previous studies showed that extracts of T.violacea induce apoptosis in cancer cells and one study reported on the isolation of a compound (methyl-ԃ-D-glucopyranoside), which is responsible for the pro-apoptotic activity of the T.violacea extract. Therefore the aim of this study was to investigate the anti-cancer activity of methyl-ԃ-Dglucopyranoside and extracts prepared from T.violacea. In this study the pro-apoptotic activity of methyl-ԃ-D-glucopyranoside and extracts prepared from T.violacea were investigated on a panel of human cancer cell lines, which included HepG2, MCF7, H157, HT29 and the non-cancerous cell line, KMST6. The induction of apoptosis was evaluated by flow cytometry using several bioassays which measures biochemical events (caspase activation, phosphatidylserine externalisation and reactive oxygen species (ROS) production that is associated with the induction of apoptosis. The results demonstrated that the effects of methyl--D-glucopyranoside on cultured cells are transient and that the cells recover from the effects of methyl--D-glucopyranoside. This suggested thatmethyl-ԃ-D-glucopyranoside is not the compound responsible for the pro-apoptotic bioactivity in the T.violacea extract. This study also showed that cytotoxic and pro-apoptotic bioactivity of the leaf-extract was significantly higher in comparison to the tuber-extract. The bioactivity of the organic solvent extracts (dichloromethane, hexane, methanol and 50% methanol/water) of T.violacea leaves was also significantly higher than water extracts of T.violacea leaves. A comparison of the different organic extracts prepared from the T.violacea leaves showed that the highest activity was observed for the dichloromethane and hexane extracts. In an effort to identify the bioactive compound(s) the dichloromethane extract was subjected to Versaflash® column chromatography. However, due to problems experienced with the solubility of the dichloromethane sub-fractions, these compounds could not be tested for their bioactivity. Palmitone (16-hentriacontanone) was identified as one of the major compounds present in the dichloromethane sub-fractions. This compound was previously shown to have anticonvulsant bioactivity but there is no evidence in the literature that it has anti-cancer or pro-apoptotic activities. Fingerprinting of the methanol extract showed the presence of long chain fatty acid derivatives, flavonoids and allicin derivatives in the methanol extract. Although, this study failed to isolate the pro-apoptotic bioactive compound(s) present in the extracts of T.violacea, it confirmed that extracts of this plant induce apoptosis in cultured human cancer cell lines.
Biomonitoring of heavy metals in the Eerste River catchment area
(University of the Western Cape, 2020) Elmayhob, Esam S. A.; Raitt, L. M.; Rajkaran, A.
The risk of increasing global pollution dictates the need to understand environmental processes and develop innovative ways to monitor pollution levels and address associated problems. In order to address this need, this study used a selection of plants leaves (Commelina benghalesis, Paspalum urvillei, Persicaria lapathifolia and Salix babylonica) as biomonitors to assess the state of the environment, more specifically the concentration of certain heavy metal pollutants (Cu, Zn, Fe, Ni, Pb and Cd) of river water and soils in the Eerste River catchment, Western Cape, South Africa.
Characterisation, Isolation, Purification and Toxigenicity ofDiplodiatoxin produced by Stenocarpella maydis in Maize
(University of the Western Cape, 2002) Rao, Shailaja Kishan; Rees, D Jasper G
Mycotoxins attract worldwide attention because of the significant economic losses associated with their impact on human health, animal productivity, domestic and international trade. Over 300 mycotoxins have been discovered, of which a few are of serious concern (Smith and Moss 1985; Rheeder et al., 1994). Exposure to these mycotoxins can produce both acute and chronic effects ranging from death to effects upon the central nervous, cardiovascular, pulmonary systems and upon the alimentary tract. Mycotoxins may be carcinogenic, mutagenic, teratogenic and immunosuppressive (Ferrante et al., 2002). Mycotoxins are currently considered as a major problem in developing countries (Miller, 1994).
Chemical investigation of some species of Amaryllidaceae from the Greater Cape Region of South Africa as a source of bioactive compounds
(University of the Western Cape, 2020) Ibrakaw, Abobaker Saleh Mohamed; Boatwright, James Stephen; Mohammed, Ahmed
The family Amaryllidaceae is widely distributed in the southern hemisphere. Members of the family are well known for their content of pharmacologically active alkaloids and represent an important epicentre of Amaryllidaceae-alkaloid diversity. Other metabolites from Amaryllidaceae, such as phenolics including flavonoids, lignans, chromones, and acetophenones, in addition to terpenoids and ceramides have been reported. Boophone haemanthoides (BHE), Crossyne flava (CRO), Clivia miniata (CME) and Nerine humilis (NHE) are members of Amaryllidaceae that have shown biological activity. Parkinson’s disease (PD) is a neurodegenerative disease that progresses with increasing age and some of its major symptoms include tremors, postural and movement related difficulties. To date, the treatment of PD remains a challenge because available drugs only treat the symptoms of the disease or possess serious side effects. In light of this, new treatment options are needed, hence this study investigates the neuroprotective effects of BHE and CRO along with the isolated compounds of BHE and CRO.
Coastal marine heatwaves: Understanding extreme forces
(University of the Western Cape, 2017) Schlegel, Robert William; Smit, Albertus
Seawater temperature from regional to global scale is central to many measures of biodi- versity and continues to aid our understanding of the evolution and ecology of biolog- ical assemblages. Therefore, a clear understanding of the relationship between marine biodiversity and thermal structures is critical for effective conservation planning. In the an- thropocene, an epoch characterised by anthropogenic forcing on the climate system, future patterns in biodiversity and ecological functioning may be estimated from projected climate scenarios however; absent from many of these scenarios is the inclusion of extreme thermal events, known as marine heatwaves (MHWs). There is also a conspicuous absence in knowl- edge of the drivers for all but the most notorious of these events. Before the drivers of MHWs along the coast of South Africa could be determined, it was first necessary to validate the 129 in situ coastal seawater temperature time series that could be used to this end. In doing so it was found that time series created with older (longer), lower precision (0.5 Degrees Celsius) instruments were more useful than newer (shorter) time series produced with high precision (0.001 Degrees Celsius) instruments. With the in situ data validated, a history of the occurrence of MHWs along the coastline (nearshore) was created and compared against MHWs detected by remotely sensed data (offshore). This comparison showed that the forcing of offshore temperatures onto the nearshore was much lower than anticipated, with the rates of co-occurrence for events between the datasets along the coast ranging from 0.2 to 0.5. To accommodate this lack of consistency between datasets, a much larger mesoscale area was then taken around southern Africa when attempting to determine potential mesoscale drivers of MHWs along the coast. Using a self organising-map (SOM), it was possible to organise the synoptic scale oceanographic and atmospheric states during coastal MHWs into discernible groupings. It was found that the most common synoptic oceanographic pattern during coastal MHWs was Agulhas Leakage, and the most common atmospheric pattern was anomalously warmoverland air temperatures.With these patterns known it is now necessary to calculate how often they occur when no MHW has been detected. This work may then allow for the development of predictive capabilities that could help mitigate the damage caused by MHWs.
Conservation and resource-use relations: Analysis for protected area expansion feasibility in the Western Cape
(University of the Western Cape, 2022) Dyssel, Michael; Knight, Richard
It is assumed that expanding the size and/or number of protected and conservation areas can contribute to more effective conservation, ecosystem services and environmental protection. Expansion is normally a response to continuous environmental threats and subsequent needs to enhance the protection and conservation of valuable biodiversity, geodiversity and heritage assets. Targets for global, regional and country-based protected area expansion are set and driven by conservation authorities across different geographical scales – from the global International Union for the Conservation of Nature (IUCN) to the local-level protected area.
Diversity and Zoogeography of South African Bryozoa
(University of the Western Cape, 2017) Boonzaaier, Melissa Kay; Gibbons, Mark J.
The taxonomic history of South African bryozoans is fragmented and outdated, with the majority of published works in the 20th Century. Sampling gaps exist in deep-sea regions and parts of the coastline, while existing collections within museums remain undetermined due to scarcity of specialist taxonomists. This project forms part of a larger project aimed at updating marine invertebrate biodiversity in South Africa. Outcomes of this project include updating bryozoan biodiversity by identifying species from existing collections housed in natural history museums (e.g., Iziko South African Museum, Cape Town and Natural History Museum, London), and analysing current regional bryozoan biogeographical and depth-related species richness patterns. The biogeography and richness of bryozoan species around South Africa was investigated using published distribution records from the literature and museum catalogues as well as examining un-worked bryozoan material from Iziko South African Museum. A total of 368 species of bryozoans were recorded, including twelve new species (Favosipora epiphyta sp. nov., Chaperiopsis (Chaperiopsis) yinca sp. nov., Aspidostoma staghornea sp. nov., Micropora erecta sp. nov., Trypostega infantaensis sp. nov., Khulisa ukhololo sp. nov., Adeonella assegai sp. nov., Celleporaria umuzi sp. nov., Hippomonavella lingulatus sp. nov., Microporella lezinyosi sp. nov., Phidolopora cyclops sp. nov. and Reteporella ilala sp. nov.) and 70 unidentified species. Distribution data for 286 valid species were separated by depth zones (shallow waters, subphotic zone, shelf edge, bathyal zone and abyss) and four biogeographic regions are recognised a priori around South Africa, namely the west, south, southeast and east coasts. This study revealed that there is a clear biogeographic structure to regional bryozoan fauna of South Africa. Species richness and endemism appear lowest on the west coast (104 species) and highest on the south coast (174 species), while local peaks are observed in the Cape Peninsula/False Bay area, East London, Durban and St. Lucia, which coincide with distinct genetic lineages for some marine taxa (e.g. octocorals, chitons, echinoderms, fishes, seaweeds). Although, the faunal break in Durban does not represent a peak in species richness in this study, but rather very low bryozoan richness, highlighting the undersampled areas north of Durban. The northward-flowing Benguela Current and strong upwelling centres may influence the low diversity on the west coast. On the south coast, the high diversity may be attributed to the Agulhas Current that can carry larvae southwards and eastward-flowing counter currents produce great variability in bryozoan communities in this region. Within any biogeographic region, bryozoan diversity was higher in shallower (< 500 m) than deeper waters, which may be attributed to sampling effort and heterogeneity (e.g. variable substrate and wave action) in shallower waters. Keywords: Bryozoa, distribution patterns, gradients, species richness, South Africa
Ecology and morphology of the Kalahari tent tortoise, Psammobates oculifer, in a semi-arid environment
(University of the Western Cape, 2012) Keswick, Tobias; Hofmeyr, Margaretha D.; Faculty of Science
Southern Africa harbours one-third of the world's Testudinid species, many of which inhabit arid or semi-arid areas, but ecological information on these species is scant. I studied the habitat, morphology and ecology of Kalahari tent tortoises over 13 months in semi-arid Savanna at Benfontein farm, Northern Cape Province, South Africa. In order to allow continuous monitoring of individuals, I attached radiotransmitters to males and females, split equally between two habitats, sites E (east) and W (west), with apparent differences in vegetation structure. Results of the study were based on data obtained from 27 telemetered tortoises and 161 individuals encountered opportunistically. Female Kalahari tent tortoises were larger than males and the sex ratio did not differ from 1:1. Based on person-hours to capture tortoises, the population appeared to have a low density, with more time required to capture a juvenile (35 hours) than an adult (10-11 hours). The frequency distribution of body size ranges was indicative of recruitment. Relative age, based on annuli counts, suggested that males were younger than females, perhaps because males as the smaller sex are more predation-prone than females. Linear relationships between annuli counts and shell volume indicated that, after reaching sexual maturity, female body size increased faster in volume than did male body size, possibly because a larger volume may enhance female reproductive success. Body condition differed between sites, sexes and among seasons. The hot and dry summer may account for low summer body condition, whereas vegetation differences and size effects, respectively, may account for the low body condition of tortoises in site W and in males. Site E was sandy with grasses, particularly Schmidtia pappophoroides, being the prevalent growth form. This habitat resembled a Savanna vegetation type Schmidtia pappophoroides – Acacia erioloba described for a neighbouring reserve. Site W was stonier, dominated by shrubs, and was reminiscent of Northern Upper Karoo vegetation (NKu3). Neither site resembled Kimberley Thornveld (SVk4), the designated vegetation type of the area. Differences in substrate and grazing intensity may have contributed to site vegetation differences. Rainfall had an important influence on seasonal vegetation. Short grass abundance correlated with rainfall and annual plants sprouted after spring rain. Refuge use changed according to season and sex. Males selected denser refuges than females did, perhaps because males were smaller and more vulnerable to predation and solar heat. Tortoises selected sparse, short grass as refuges in cool months, probably to maximise basking whilst remaining in protective cover. During hot periods, mammal burrows were preferred to vegetation as refugia. The smaller males spent more time in cover than females, which may be related to predator avoidance or thermoregulation. Females spent more time basking than males, perhaps due to their larger size and to facilitate reproductive processes. Tortoises did not brumate, but through a combination of basking, and orientation relative to the sun in their refuges, managed to attain body temperatures that allowed small bouts of activity. Body temperature for active tortoises was similar among seasons, and was higher for more specialised active behaviours, such as feeding and socialising, than for walking. Increased activity by males in spring could relate to mating behaviour while females were more active in autumn, when they foraged more than males, perhaps due to the high cost of seasonal reproductive requirements. Males displaced further per day than did females, but home range estimates did not differ between sexes. Annual home range estimates varied substantially among individuals: 0.7–306 ha for minimum convex polygons and 0.7–181 ha for 95% fixed kernel estimates. The ability to cover large areas would assist tortoises in finding resources, e.g., food, in an area where resource distribution may be patchy. Differences among seasonal home ranges and movements probably reflect seasonal climatic change; activity areas shrinking when temperatures were extreme. In order to assess the effects of a semi-arid environment on the morphology of P. oculifer, I compared its morphology to that of its ‘cool-adapted’ sister taxon Psammobates geometricus, using live and museum specimens. Both P. oculifer and P. geometricus are sexually dimorphic and differences between the two species could indicate environmental or sexual selection effects, or a combination of the two. The shorter bridge length, which allowed more leg space, and wider front feet in P. oculifer cohorts probably represent traits for manoeuvring in a sandy habitat, while wider heads in P. oculifer possibly relate to interspecific differences in diet. The flatter shell in female P. oculifer, relative to P. geometricus, may represent a trade-off between space for reproductive structures, e.g., eggs, and the need to fit into small refuges, e.g., mammal burrows. Male P. oculifer had wider shells, more space around their hind legs, and wider hind feet than P. geometricus males had, all characteristics which may assist males to fight and mate in a sandy environment.
The ecology of tadpoles in a temporary pond in the Western Cape with comparisons to other habitats
(University of the Western Cape, 2006) Hopkins, Samantha; Channing, Alan; Faculty of Science
This work centered on the tadpoles in a temporaray pond in the middle of Kenilworth racecourse, Cape Town, South Africa. Trapping was carried out over two wet seasons and five species were found. The racecourse was selected to investigate the tadpole community occupying temporary winter pools. The main focus of this study was the community of tadpoles that occur in the ephemeral ponds in the centre of Kenilworth Racecourse. This study was a very broad insight into tadpole ecology in the Western Cape.
The genus Spongites (Corallinales, Rhodophyta) in South Africa
(University of the Western Cape, 2019) Puckree-Padua, Courtney Ann; Maneveldt, Gavin W.; Gabrielson, Paul W.
Coralline red algae (Corallinales, Hapalidiales, Sporolithales: Corallinophycidae, Rhodophyta) are widespread and common in all the world’s oceans (Adey & McIntyre 1973; Johansen 1981; Littler et al. 1985; Björk et al. 1995; Aguirre et al. 2007; Harvey & Woelkerling 2007; Littler & Littler 2013). They achieve their highest diversity in the tropics and subtropics (Björk et al. 1995; Littler & Littler 2013; Riosmena-Rodríguez et al. 2017), and within the photic zone of rocky shores (Lee 1967; Littler 1973; Adey 1978; Adey et al. 1982; Steneck 1986; Kendrick 1991; Kaehler & Williams 1996; Gattuso et al. 2006; van der Heijden & Kamenos 2015; Riosmena-Rodríguez et al. 2017) where they serve as important carbonate structures (Adey et al. 1982; Littler & Littler 1994, 1997; Vermeij et al. 2011) and habitats for a host of marine species (Foster 2001; Amado-Filho et al. 2010; Foster et al. 2013; Littler & Littler 2013; Riosmena-Rodríguez et al. 2017). Coralline algae are resilient, inhabiting extreme conditions that include: low temperatures (Adey 1970, 1973; Freiwald & Hendrich 1994; Barnes et al. 1996; Freiwald 1996; Aguirre et al. 2000; Roberts et al. 2002; Björk et al. 2005; Martone et al. 2010); limited light exposures (Adey 1970; Littler & Littler 1985; Littler et al. 1985; Liddell & Ohlhorst 1988; Dullo et al. 1990; Littler & Littler 1994; Iryu et al. 1995; Stellar and Foster 1995; Gattuso et al. 2006; Aguirre et al. 2007; Littler & Littler 2013); severe wave action (Steneck 1989; Littler & Littler 2013); intense grazing pressures (Steneck 1989; Steneck & Dethier 1994; Maneveldt & Keats 2008; Littler & Littler 2013), highly fluctuating salinities (Harlin et al. 1985; Barry & Woelkerling 1995; Barnes et al. 1996; Wilson et al. 2004); including occurring in freshwater (Žuljevic et al. 2016), and constant sand scouring (Littler & Littler 1984; D’Antonio 1986; Kendrick 1991; Chamberlain 1993; Dethier 1994).
A global revision of the nongeniculate coralling algal genere Porolithon Foslie (defunct) and Hydrolithon Foslie (Corallinales, Rhodophyta)
(University of the Western Cape, 2005) Maneveldt, Gavin W.; Keats, Derek; Weitz, Frans; Faculty of Science
The purpose of this thesis was to provide a revision and characterization of the species of nongeniculate coralline algae previously ascribed to the now defunct genus Porolithon; to provide a modern account of selected taxa from the genus Hydrolithon and descriptions of taxa found to conform the generic delimitation of Hydrolithon and to use a phenetic cluster analysis to determine the taxonomic relationships between the various taxa ascribed to the genera Polorithon and Hydrolithon.
Heteroscleromorph demosponge taxonomy and diversity of the Amathole region (Eastern Cape, South Africa)
(University of Western Cape, 2022) Payne, Robyn Pauline; Samaai, Toufiek
Sponges are functionally important and ubiquitous components of the global marine benthos. South Africa accounts for roughly 4% of the global marine sponge diversity, comprising 374 described species and seven varieties/forms, with elevated apparent endemism (59.3%). However, an estimated 900 sponge species are thought to be undescribed, and much work is needed to update and expand our knowledge of the South African sponge fauna. The Amathole region is situated offshore of the Amathole District, around the city of East London, on the south-east coast of South Africa.
How do teachers and learners navigate the terrain of ecology and what are the associated conceptual understanding?
(2011) Raitt, Rosemary Ruth; Holtman, L.B
This thesis relates the teaching of ecology in schools to the requirements of the National Curriculum Statements, Grades R-9 and Grades 10-12, for Natural and Life Sciences. It examines the conceptual understanding of the learners to determine their level of bioliteracy. The effectiveness of various teaching strategies in enhancing bioliteracy is considered. The study was a case study involving classroom observations of Grades 4 to 7 at a primary school and Grades 8 to 11 at a high school in the Western Cape of South Africa, and the administration of a misconceptions questionnaire to learners in Grades 8 to 11. The Department of Education did not allow researchers into the Grade 12 classes. To counter this, the misconceptions questionnaire was also administered to first-year Life Science students and to students in one second-year course in the Department of Biodiversity and Conservation Biology. It was administered to a small sample of the Postgraduate Certificate in Education (PGCE) students (prospective teachers) at the University of the Western Cape, in order to determine whether misconceptions would be carried into their teaching. In-depth interviews which focussed on the particular student's misconceptions were used to verify the misconceptions which the first-year students held. The questionnaire revealed that learners lacked an understanding of photosynthesis and respiration, which forms the basis for an understanding of food chains and energy flow within an ecosystem. Learners were confused about ecology and did not understand basic concepts. The misconceptions held in high school carried over to university, as shown by the fact that the first-year Life Science students, tested before they had had any lectures, still held many of the misconceptions that were found among the high school learners. A few second-year students still held misconceptions, but their understanding of photosynthesis and respiration was better than that of first-year students. The questionnaire also revealed that learners lack language skills. Good language skills are necessary for the development of scientific literacy.
How do teachers and learners navigate the terrain of ecology and what are the associated conceptual understandings?
(University of the Western Cape, 2011) Raitt, Rosemary Ruth; Holtman, L.B.
This thesis relates the teaching of ecology in schools to the requirements of the National Curriculum Statements, Grades R-9 and Grades 10-12, for Natural and Life Sciences. It examines the conceptual understanding of the learners to determine their level of bioliteracy. The effectiveness of various teaching strategies in enhancing bioliteracy is considered. The study was a case study involving classroom observations of Grades 4 to 7 at a primary school and Grades 8 to 11 at a high school in the Western Cape of South Africa, and the administration of a misconceptions questionnaire to learners in Grades 8 to 11. The Department of Education did not allow researchers into the Grade 12 classes. To counter this, the misconceptions questionnaire was also administered to first-year Life Science students and to students in one second-year course in the Department of Biodiversity and Conservation Biology. It was administered to a small sample of the Postgraduate Certificate in Education (PGCE) students (prospective teachers) at the University of the Western Cape, in order to determine whether misconceptions would be carried into their teaching. In-depth interviews which focussed on the particular student's misconceptions were used to verify the misconceptions which the first-year students held. The results of the misconceptions questionnaire for the PGCE students revealed that a high percentage of them had very little understanding of ecology and that they held several common misconceptions, despite having completed a degree which qualified them to teach Life Science or Natural Science in high school. This study demonstrated that more attention needs to be given to the proper training of Life Science teachers, and to instruction in practical work and fieldwork in the Life Sciences.
How Do Teachers and Learners Navigate the Terrain of Ecology and What are the Associated Conceptual Understandings?
(University of the Western Cape, 2011) Raitt, Rosemary Ruth; Holtman, L.B.
This thesis relates the teaching of ecology in schools to the requirements of the National Curriculum Statements, Grades R-9 and Grades 10-12, for Natural and Life Sciences. It examines the conceptual understanding of the learners to determine their level of bioliteracy. The effectiveness of various teaching strategies in enhancing bioliteracy is considered. The study was a case study involving classroom observations of Grades 4 to 7 at a primary school and Grades 8 to 11 at a high school in the Western Cape of South Africa, and the administration of a misconceptions questionnaire to learners in Grades 8 to 11. The Department of Education did not allow researchers into the Grade 12 classes. To counter this, the misconceptions questionnaire was also administered to first-year Life Science students and to students in one second-year course in the Department of Biodiversity and Conservation Biology. It was administered to a small sample of the Postgraduate Certificate in Education (PGCE) students (prospective teachers) at the University of the Western Cape, in order to determine whether misconceptions would be carried into their teaching. In-depth interviews which focused on the particular student's misconceptions were used to verify the misconceptions which the first-year students held. The questionnaire revealed that learners lacked an understanding of photosynthesis and respiration, which forms the basis for an understanding of food chains and energy flow within an ecosystem. Learners were confused about ecology and did not understand basic concepts. The misconceptions held in high school carried over to university, as shown by the fact that the first-year Life Science students, tested before they had had any lectures, still held many of the misconceptions that were found among the high school learners. A few second-year students still held misconceptions, but their understanding of photosynthesis and respiration was better than that of first-year students. The questionnaire also revealed that learners lack language skills. Good language skills are necessary for the development of scientific literacy. Three of the seven teachers whose classes were observed admitted to finding it difficult to teach ecology. One of them suggested that the Department of Education provide special training to teachers in this area of teaching. Issues relevant to South African problems were not addressed in any of the classes observed. - Too-little time is allocated to the teaching of ecology to allow for any discussion of social issues relating to this subject. Time, resource constraints, and a lack of training in teaching ecology make it impossible for teachers to fulfil the requirements of the curriculum. Grade 10 learners were required to identify abiotic and biotic factors operating in a local ecosystem, and to describe the trophic relationships present. Grade 11 learners were required to study and report on one local example of human influence on the environment. These requirements were not met. While teachers were prepared to take learners out of the classroom to study ecology, some of them were not able to do so because of extremely large classes and associated problems. The results of the misconceptions questionnaire for the PGCE students revealed that a high percentage of them had very little understanding of ecology and that they held several common misconceptions, despite having completed a degree which qualified them to teach Life Science or Natural Science in high school. This study demonstrated that more attention needs to be given to the proper training of Life Science teachers, and to instruction in practical work and fieldwork in the Life Sciences.
Impacts of degradation on critically endangered Oudtshoorn Gannaveld
(2010) Wheeler, Alan David; Knight, Richard
In the Succulent Karoo biome of South Africa vegetation degradation by overgrazing is a recognized threat to biodiversity. In the eastern Little Karoo region of the Western Cape Province, ostrich farming has degraded large areas of natural vegetation, particularly in the Gannaveld habitat of the Oudtshoorn basin. Little quantified vegetation data exists on the impacts of degradation and the composition of the Gannaveld vegetation types. This study quantifies the composition of Oudtshoorn Gannaveld and the impacts of degradation on this critically endangered vegetation type. The diversity of this vegetation type is added to by the occurrence of mima-like circular soil mounds, termitaria, which support distinctive plant assemblages. Perennial plant data and soil data were collected from the largest remaining remnant of Oudtshoorn Gannaveld perceived to contain different levels of degradation from near pristine to severely degraded. The results show 72 species in 49 genera and 17 families were recorded with the Aizoaceae, Asteraceae and Amaranthaceae families being dominant. The off termitaria plant community is dominated by the Asteraceae, Aizoaceae and Crassulaceae families while the on termitaria community is dominated by the Asteraceae, Amaranthaceae and Zygophyllaceae families. Four levels of degradation were identified in each of the broader on and off termitaria communities. It was found that grazing and trampling induced degradation on termitaria results in the loss of perennial plant cover and plant litter and an increase in bare ground while degradation off termitaria results in a loss of species. There are changes in soil chemistry both on and off termitaria as a result of vegetation degradation. Degradation results in palatable species being replaced by unpalatable and disturbance indicating species. Perennial plant cover off termitaria is resilient to grazing and trampling, however species richness, plant functional type composition and the abundance of individual species are not. Species richness on termitaria is resilient to grazing and trampling but cover, plant functional type composition and the abundance of individual species are not. Degradation results in shifts from succulent and woody shrub dominated communities to dwarf succulent and dwarf succulent shrub dominated communities. These changes hold implications for agriculture,biodiversity conservation and the provision of ecosystem services.
Linking biology and sustainable livelihoods to the proposed establishment of community -based Eucheumoid farming in southern Kenya
(University of the Western Cape, 2005) Wakibia, Joseph .G; Keats, Derek; Raitt, Lincoln; Bolton, John
Growth rates of three commercial eucheumoids: brown Eucheuma denticulatum and green and brown Kappaphycus alvarezii were studied at three sites (Gazi Bay, Kibuyuni and Mkwiro) in southern Kenya. The study was conducted using the fixed off-bottom rope technique over a 15 month period from August 2001 to October 2002, in 4 plots (5 m x 1.5 m) set up at each site. The brown E. denticulatum had the highest mean growth rate over the entire period of 4.7% day-I compared to the green and brown K. alvarezii which were 4.3% day l and 4.2% dayl, respectively. Mean relative growth rates were highest at Gazi (5.6% dayl), and lowest in Kibuyuni (3.2% day-I) with intermediate values of 4.8% dail at Mkwiro. Increased water motion was observed to increase thallus nitrogen and hence the growth of eucheumoids. The 'ice-ice' syndrome affected both brown E. denticulatum and brown K. alvarezii but not green K. alvarezii. Mean growth was higher during the southeast monsoon (4.7% day+) than during the northeast monsoon (4.0% dayl).The carrageenan characteristics of the three morphotypes were measured for 12 months. The highest carrageenan yield was obtained for green K. alvarezii (59.1% dry wt), whereas the average carrageenan yield for brown K. alvarezii was 56.5% dry wt and 56.6% dry wt for brown E. denticulatum. The plants at Gazi (58.0% dry wt) had a slightly, though significantly, higher carrageenan yield than both those at Kibuyuni (57.1 % dry wt) and Mkwiro (57.3% dry wt). However, from a commercial point of view the differences in carrageenan yields were not meaningful. Highest gel strengths were obtained in carrageenans from green K. alvarezii (1042.1 g cm") and brown K. alvarezii (1053.7 g ern"), whereas low values of 100.8 g ern" were obtained for brown E. denticulatum. The brown E. denticulatum had carrageenan with higher viscosity (81.7 mPa.s) and sulphate content (29.1% dry wt) than both green and brown K. alvarezii. The gel viscosities of all the morphotypes were higher during the southeast monsoon (67.3 mPa.s) than during the northeast monsoon (46.3 mPa.s) and were positively correlated with gel strengths.A survey was conducted among households in the three villages, from April to September 2001 to assess their socio-economic characteristics. There were 182 household heads interviewed; about 20% were women. Fishing was the main source of livelihood for about 48% of the household members. In 2001, the average monthly income for the surveyed households was Kshs. 9904 (1 US$=75 Kshs.), with about 67% having less than Kshs. 10 000. The average prevalence of poverty among the households surveyed was 45.1% with 38.8%,54.8% and 46.7% of households in Gazi, Kibuyuni and Mkwiro villages, respectively, living below the poverty line of Kshs. 1239 per month per adult person. An economic feasibility study for growing brown E. denticulatum and brown K. alvarezii in pilot farms of 0.1 ha was conducted at Gazi and Kibuyuni. A higher yield of 793 kg dry wt was obtained for plants grown at Gazi than those at Kibuyuni (793 kg dry wt). The net income derived from E. denticulatum was estimated at Kshs. 7549 annually in a 0.1 ha seaweed farm. A higher annual income of Kshs. 49 126 was generated from K. alvarezii. The rate of return on investment in farming E. denticulatum ranged from 15 to 63%, while 122 to 380% for K. alvarezii. The pay back period was shorter for the latter (0.3 to 0.7 years) than the former (1.2 to 2.7 years).A cross-sectoral policy analysis regarding legislation and policy relevant to the introduction and development of eucheumoid cultivation in Kenya, with particular reference to Kenyan legislation was conducted. The analysis showed that there is no system of promoting or regulating mariculture, though there are fragmented regulations that are scattered among the policies, Acts and regulations of various institutions. Such regulations were not designed specifically for mariculture and as a result they do not fully address the needs of mariculture. The establishment of a national mariculture development programme in Kenya is proposed as a means to develop and manage the farming of marine resources, including seaweeds.

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