Magister Scientiae (Biodiversity and Conservation Biology) - MSc (Biodiv & Cons Biol)

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    Abalone nutrition – growth performance of Haliotis midae in relation to variable artificial feeds
    (University of Western Cape, 2020) Mohamed, Riaaz; Gibbons, Mark J.
    Abalone are among the most expensive and sought-after seafood subjects. In South Africa, Haliotis midae is the only commercially significant abalone species and it has become increasingly sold on the global market. The importance of abalone as a mariculture subject has triggered extensive research into maximizing production, with particular emphasis on optimizing growth rates. This study aimed to assess the growth performance of Haliotis midae relative to 1) standard pelleted feed, and 2) kelp-inclusive pelleted feed. I assessed feed stability of the dietary treatments and growth parameters associated with abalone weight gain. Temperature and time of feed submersion were found to significantly affect feed stability. Although there were no significant differences in water stability between feeds, the kelp-inclusive feed produced significantly lower total suspended solids (TSS) than the standard pelleted feed at upper time-temperature combinations.
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    Acoustic signalling in bladder grasshoppers (orthoptera: pneumoridae)
    (University of the Western Cape, 2022) Lagaa, Sasya; Couldridge, Vanessa
    Sound plays a vital communicative role in many Orthopteran insect species. Acoustic signals are often used during courtship behaviour and mate location. The Pneumoridae, commonly referred to as bladder grasshoppers, are a family of insects native to southern and eastern Africa. They are highly adapted for long-distance sound communication, with the males emitting very loud advertisement calls that are typically distinctive to each species. However, relatively few previous studies have examined sound communication within the entire family, and little is known about interspecific variation in signals and how this relates to evolutionary history. The aim of this study was to compare acoustic signal characteristics, as well as the morphology of the sound-producing structures, across multiple species in order to better understand morphological constraints on sound production.
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    Adequacy of existing protected areas in conserving biodiversity at global and regional levels in relation to socio-economic conditions
    (University of the Western Cape, 2005) Gaika, Lindiwe; Knight, Richard; Faculty of Science
    At a meeting of worl leaders at the United Nations Conference on Environment and Development in Rio de Janeiro in 1992, it was recognized that because of the tremendous increase in the size of the global populations (which now is estimated to exceed six billion), there were concerns that global biodiversity was at risk if insufficient land were not put aside for conservation within formal Protected Areas. The primary aim of this study was to compare investment in Protected Areas in relation to socio-economic conditions at global and regional levels.
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    Amphibian monitoring in Kakamega Forest, Kenya
    (2007) Wairimu, Vincent Muchai; Channing, A.; Veith, M.
    Since the late 1970 there has been increased concern of amphibian decline and extinction. Several causes for the worldwide declines have been suggested and include ultraviolet radiation, predation, pollution, climate change, diseases and habitat modification. To counter this, more research on the subject has been encouraged of which long term monitoring has been suggested as a research method. The study was conducted in Kakamega Forest in Kenya, which is the country's remnant of the once vast Guineo-Congolian forest. A rectangular transect whose sides measured 600 m in total was established and transect walks were carried out every two weeks for two consecutive days between 2002 and 2006. 24 species were targeted in the study and were sampled through VES and AES and data recorded in a GPS and later downloaded. In this study I examined the influence of rainfall, temperature, habitat and moon phases on the activity of frogs in Kakamega Forest. I also determined under which weather conditions sampling was more efficient. When monitoring was carried out by two observers I tested whether their data were similar. Data were analysed using non-parametric methods (Kruskal-wallis and Tukey test), species abundances analysed using EstimateS..Out of the 24 targeted species only 14 were recorded, with a total of 535 specimens being counted mostly at night. Most frogs in Kakamega Forest were more active in temperatures between 20 and 25oC. There was not much variation and there was no frog activity when the temperature was extremely high. There was rainfall throughout the year and there was no significant differences in the number of frogs counted in rainfall above 200 mm or below 200 mm. There was no significant difference in the number of specimens found in the different vegetation segments in the forest. More amphibians were caught under cloudy, rainy and clear conditions at night than under any weather condition during the day. During the day, more amphibians were caught during cloudy conditions than when it rained or when there was no cloud cover. There was no difference in catch among night conditions and there was no difference between clear and rainy days In Kakamega Forest, night is the best time to sample amphibians. In terms of weather it is best to sample when it is cloudy both during the day and at night. There were no differences in sampling abilities between two observers tested under similar weather conditions.
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    An acoustic, genetic and morphological review of the genus Bullacris (Orthoptera; Pneumoridae)
    (University of the Western Cape, 2017) Gordon, Mikhaila Leigh; Couldridge, Vanessa
    Bladder grasshoppers (Orthoptera: Pneumoridae) are nocturnal African herbivores that are endemic to the coastal regions of southern Africa. They rely heavily on sound communication for mate location and have a unique body structure, with an inflated abdomen seen only in males that aids in sound production. They have a continuous distribution that extends along the coast of South Africa from Namibia, into the eastern regions of Mozambique and beyond, as far as Uganda. Bullacris is the largest genus within the Pneumoridae family. Members of this genus are mostly found within South Africa and inhabit different vegetation biomes, namely the Succulent- Karoo, Fynbos and Savannah biomes. There are currently seven described species within the genus, based solely on morphological differences. However, these morphological differences are not well defined for all species pairs, leading to some degree of uncertainty in species delineation.
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    An analysis of the fire regime and its effects on post-fire recovery in Namaqualand Granite Renosterveld vegetation
    (University of the Western Cape, 2017) Simons, Megan Brigette; Knight, Richard
    Namaqualand Granite Renosterveld (NGR) is a fire-prone shrubland largely confined to the Kamiesberg Uplands. More than 20% has been transformed by agricultural activities such as grazing and dryland cropping. The history of fires of Namaqualand Granite Renosterveld was assessed over a period from 2000 - 2015. Furthermore, this study aimed to assess the effects of fire and grazing on the dynamics of Elytropappus rhinocerotis and the post-fire vegetation recovery. Satellite imagery, field observations and combination of field sampling techniques were used to compile a comprehensive fire database and to collect data on vegetation parameters. The Kamiesberg Uplands has a human-induced fire regime with a fire frequency of 4.2 years, which appears to be shorter for NGR compared to other Renosterveld - types. The majority of the fires were in summer and early autumn which is the ecologically accepted season with high fire intensities. Fire Danger Index ratings for summer burns were in the dangerous and very dangerous categories. In terms of cover, the distances between E. rhinocerotis individuals were significantly more on the burnt than on the unburnt sites. The density of unpalatable species on the burnt sites is also strongly associated with E. rhinocerotis. Elytropappus rhinocerotis appears to facilitate a role as a nurse-plant for various species in renosterveld. The local biotic and abiotic conditions, allows E. rhinocerotis to maintain its abundance, thus displaying niche construction by a single species.
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    An Investigation of Benthic Epifauna to Support Classification and Mapping of Outer Shelf Ecosystems in KwaZulu-Natal
    (University of the Western Cape, 2017) Makwela, Mapula Salome; Smit, AJ
    Ecosystem classification and mapping are foundational steps for effective ecosystem-based marine spatial planning, marine ecosystem assessment and integrated ocean management. The aims of this study were to interrogate and refine existing ecosystem classification and maps using quantitative data for epifaunal communities and to investigate the potential physical drivers which may contribute most to the distribution patterns of these ecosystem types. A total of 27 sites between Pennington and Ballito on the east coast of South Africa, including unconsolidated sediment, mixed and reefs habitat types, in the 48 to 85m depth range, was examined. Epifauna data were quantified from seabed imagery collected by remotely-operated vehicle covering more than 13 130 epifaunal individuals counted representing over 170 morphospecies from five taxa. Multivariate analyses of data from 17 sites surveyed in southern KwaZulu-Natal (KZN) revealed that epifauna at unconsolidated sediment sites were significantly different to that occurring on either mixed or reef substrates and epifauna occurring on mixed substrates were also significantly different to those occurring on reefs. Epifauna at mixed sites were more similar to epifaunal assemblages at reef sites than epifauna at unconsolidated sediment sites.
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    Analysis of three wetland medicinal plants: Centella asiatica, Cyperus longus and Typha capensis found in the Western Cape Province of South Africa.
    (University of the Western Cape, 2017) Saibu, Olusola Surajudeen; Smit, A.J.; Mabusela, W.T.
    South Africa is recognised worldwide for its rich diversity of plants, many of which have been used in ethno-medicine. However, the use of wetland plant species in ethno-medicine required further investigations. This research is aimed at investigating three wetland medicinal, plant species, Centella asiatica, Cyperus longus and Typha capensis based on their geographical, seasonal, mineral nutrient (Fe, Mn, Ca, Mg, K and Na) and secondary metabolite characteristics. Samples of each species were collected from Grabouw, Kelderhoff, Kenilworth, Pringle Bay, University of the Western Cape (UWC) and Worcester within the Western Cape Province of South Africa. Specimen and soil collections were carried out during autumn, spring, summer and winter of 2014. Both plant and soil samples were acid digested and mineral nutrient concentrations in the samples were analysed using an atomic absorption spectrometer (AAS). Secondary metabolites were determined using analytical TLC on normal phase Merck-Silva gel coated aluminium plates as well as by using HPLC separation from crude extracts of C. asiatica, C. longus and T. capensis using LC-MS hardware from Agilent. The elemental analysis of soil samples showed that Ca, K, Mg, Mn and Zn concentrations were predominantly low. Soil mineral concentrations increased progressively from inland (Worcester) towards the coastland in the south (Pringle Bay). Calcium and sodium concentrations, in particular, were higher in soil samples obtained from Grabouw (inland south) and decreased northward towards Worcester. Comparatively, plant mineral concentrations were generally higher than soil concentrations. The high concentration of some of these essential elements, in selected plants is an indication that these plant species could be a good source of essential elements. High concentrations of phytochemicals were found in Centella asiatica during winter, while Cyperus longus and Typha capensis exhibited high concentrations during autumn indicating variation in respect of season. Consequently, harvesting of the studied plants should be done at the season with a relatively high phytochemical concentration. Studies are needed to investigate the extent of pesticide or herbicide contamination in wetland plants to protect the health of users. The LC-MS analyses of the three study species showed that seasonal variation affects metabolite constituents and moreover that these metabolite constituents differ from one locality to another. The seasonal variation of the elements in the studied medicinal plants justified the importance of harvesting seasons in the optimal utilization of the studied plants for medicinal purpose. s, for C. asiatica, anti-bacterial treatments for C. longus and fertility enhancement and birth control for T. capensis.
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    Applications of DNA-barcoding in the identification and understanding of grass invasions in Southern Africa
    (University of the Western Cape, 2014) Brown, Carly; Boatwright, Stephen J.; Van der Bank, Michelle
    The spread of invasive species is one of the greatest threats to global biodiversity. Alien plant invasions also have serious economic impact in terms of the delivery of ecosystem goods and services. Studies of biological invasions in southern Africa have tended to overlook grasses (family Poaceae), although there are many naturalised species in the region. Only a few of these, all perennials, have been officially categorised as invasive in South Africa, but in the winter rainfall region of the Western Cape, grass invasion especially by Mediterranean European annuals have also been noted. These grasses can be difficult to identify. DNA barcoding has been suggested as an alternative method of identifying grasses in the hope of facilitating identification of existing invaders and preventing future invasions. In this study a list of all known naturalised grasses in South Africa was compiled, and a DNA barcoding reference database was assembled for these naturalised grass species as well as for native southern African grass species. The two official markers for plant DNA barcoding (rbcLa + matK) were used in barcoding and phylogenetic analyses, both individually and in combination. The barcoding data was assessed for identification efficacy using three distance-based metrics and one tree-based metric in the R package SPIDER, both including and excluding singleton data. This study lists 128 naturalised grass species and subspecies found in South Africa. In the DNA barcoding analyses, matK was found to perform better as a single barcode than rbcLa, with identification success rates of up to 84% for matK and 76% for rbcLa, using the most successful metric which was the Nearest Neighbour criterion for both of these markers in the data sets without singletons. The combined rbcLa + matK data set performed better than either of the two individual markers, with identification success rates of up to 91% in the data without singletons, with the most successful metric again being the Nearest Neighbour criterion. The combined rbcLa + matK data would therefore be the recommended DNA barcode for southern African grasses of the three data sets tested, based on the results of this study. Phylogenetic trees were constructed with the DNA barcoding data using Bayesian Inference (BI) and Maximum Parsimony (MP) to assess the usefulness of the data in phylogenetic studies and to confirm the efficacy of this grass DNA barcoding data when using tree-based methods of identification. Both the matK and combined datasets resolved all of the grass tribes represented in this study as monophyletic, but the rbcLa data did not.
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    Applying a lagrangian trajectory model to investigate and describe the distribution of drifting ecklonia maxima within the benguela upwelling system
    (University of the Western Cape, 2023) Coppin, Ross Mark; Smit, AJ
    Macroalgal morphological variation is determined to a large extent by a combination of environmental factors, with wave exposure and temperature perhaps the main influences, as they are key environmental properties to which a species becomes locally adapted. Macroalgae have shown to exhibit different responses to different magnitudes of exposure to waves, such as reduction in overall size and strength increasing traits. In terms of temperature, warmer environments have been shown to reduce the overall size of resident and transplanted species. However, none of the past studies have identified specific wave and temperature metrics responsible for the morphological adaptation macroalgae exhibit. Past research has often used simple or two-dimensional models of wave exposure, which do not take into account important aspects of the nearshore environment such as wave breaking, refraction and diffraction. Furthermore, past studies have often used satellite-derived datasets as sources for temperature data; however, such data have been shown to have large bias when applied to the nearshore environment. This study used in situ temperature data and wave power metrics calculated from a 3D-numerical model to identify specific temperature and wave metrics responsible for morphological adaptation of the kelp, Ecklonia maxima and Laminaria pallida. Between temperature and wave exposure, the results identify wave exposure as the main influencer of morphological adaptation while identifying specific wave metrics. Furthermore, the results show differences in wave metrics between species, and between deep and shallow populations. The findings from this chapter were used in the next chapter to investigate the role of hydrodynamic and wind drag on floating kelp trajectory. Ocean currents act as an essential dispersal mechanism of natural and anthropogenic material on the ocean surface. Macroalgae are one of the essential natural dispersal vectors of marine organisms and are regarded as the ‘tumble-weed of the ocean.’ Despite many studies on the topic, the relative role of wind and surface currents in influencing the trajectory of macroalgal dispersal is still uncertain. Past studies focused on kelp-rafts, which can vary significantly in size, making it difficult to form a consensus on the relative role of wind versus surface currents. In addition, these studies have not considered surface area in relation to drag characteristics of the macroalgae, both of which have been shown to play a role in the trajectory and accumulation of flotsam. Advances in Lagrangian trajectory modelling have been rapid in recent years and allow the use of numerical experiments to investigate trajectories of flotsam in the ocean. This study aimed to shed light on the relative role of wind versus surface currents and the role of drag in macroalgal trajectory and accumulation. We focused on solitary kelp plants. This was achieved by comparing simulations of virtual kelp ‘particles’ which incorporate drag with that of purely Lagrangian particles (no drag).
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    Assessing livestock farmers' ecological knowledge and adaptation to climate and environmental change in arid regions of South Africa
    (University of the Western Cape, 2017) Ntombela, Khululiwe Primrose; Knight, Richard
    Challenges that come with micro-level climate change projections have resulted in the inadequacy of our understanding of local climatic changes and the appropriate adaptation strategies. This has resulted in indigenous communities relying on their local knowledge for local scale climatic changes and suitable adaptation practices. Coping and adapting to climate and its impacts has been occurring since human existence, however, humans are still vulnerable due to the rapid rate that the climate is changing. Adaptation is vital for all global people, especially living in semi-arid or arid regions, as it provides a solution for food shortages and livelihoods. Global livestock farmers have, over many years, accumulated local ecological knowledge; and it is from this knowledge that decisions are made. Local knowledge related to adaptation to climate change and variability has largely not been recognized or documented and it is only lately that it is deemed to be critical in formulating policies to mitigate the harsh effects of the rapidly changing climate. This study was focused on the local knowledge and understanding of climate change and variability (and associated environmental change) with its impacts and adaptation of communal livestock farmers in the semi-arid regions of the Northern Cape Province in South Africa. Two communal areas namely, Leliefontein and Steinkopf in Northern Cape served as study sites. A case study approach, with triangulation of focus group discussions and semistructured interviews, was used. The focus group discussions were aimed at drawing up a seasonal calendar, where 10 livestock farmers from Leliefontein and 14 from Steinkopf participated. The focus group discussions were followed by indepth semi-structured interviews, where a total of 20 livestock farmers from each study site were interviewed. While various other studies highlight the lack of awareness and understanding of climate change among livestock communal farmers, this study found that 90 % and 55 % of the interviewed Steinkopf and Leliefontein livestock farmers had an understanding of the phenomenon. The interviewed farmers referred to the phenomenon of climate change as "seasonal shifts" that they have been experiencing. Findings of the study indicated that intergeneration knowledge transfer and media sources contributed as sources of climate and farming management information. The basic, but wealthy knowledge of farmers informs them of potential climate change impacts and possible adaptation strategies. The study also revealed that even though adaptation measures are being carried out by livestock farmers I n the two study sites, that there are general barriers which include financial, biophysical environment, social and institutional barriers that inhibit effective adaptation. Recommendations from this study were that policies should consider and protect local knowledge; and that the factors that affect successful adaptation strategies of communal livestock farmers should be considered when adaptation programmes are planned.
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    Assessing the quality of forage for livestock in a semi-arid pastoral system in South Africa
    (University of the Western Cape, 2016) Amary, Nefza Mohamed; Boatwright, James S.; Samuels, Mogamat Igshaan; Hattas, D.; Cupido, C. F.
    This study evaluated the nutritional quality of the forage plants in Namaqualand Granite Renosterveld vegetation in the Kamiesberg uplands of the Leliefontein communal area, South Africa. Determining the quality of forages is one of the most important factors necessary for the effective management of rangelands as it impacts on the nutrient needs of animals and consequently, the grazing capacity in rangelands. The edible portions of various forage plants were collected in the wet and dry seasons in 2012 and 2013 after which the nutritional quality (mineral nutrient content; crude protein (CP); fibre, neutral detergent fibre (NDF) and acid detergent fibre (ADF); dry matter digestibility (DMD); dry matter intake (DMI); metabolizeable energy (ME); and relative forage value (RFV)) as well as the anti-nutritional quality (total phenolics (TP); condensed tannins (CT); and silicon (Si) concentrations) of the plants were determined. Plants were thereafter grouped into their respective growth forms: grasses (15 species), herbs (15 species), leaf succulents (17 species), non-succulents (134 species), reeds (7 species), trees (8 species) and stem succulents (2 species) for statistical analyses. There were generally only a few significant differences for each forage growth form, when comparing the nutritional and anti-nutritional qualities between the two seasons. Certain forage types such as leaf succulents were found to have a high nutritional value in terms of their mineral nutrient content, CP, DMD and ME , but were also found to contain high concentrations of one or more anti-nutritional factors. However, within each season, results showed that for both the nutritional quality and anti-nutritional quality, there was a significant difference between the different growth forms within each season. This suggests that both of these quality parameters are essential in order to draw meaningful conclusions regarding forage quality of these semi-arid rangeland plants. Further research is needed at the species level to determine what plant species are the most nutritious in terms of both nutritional and anti-nutritional quality in order to inform the potential production of these species on a commercial scale.
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    Assessing the vegetation and soil microbial ecology of renosterveld rangelands around Nieuwoudtville, Northern Cape Province
    (University of the Western Cape, 2015) Solomon, Gabrielle Marie; Weitz, Frans M.; Cupido, C. F.; Swart, W. J.
    The Bokkeveld Plateau, a region hosting high plant endemism, is home to two arid mountain centre renosterveld types. One, Nieuwoudtville Shale Renosterveld, has partially been transformed into croplands and pastures, with about 40 % remaining as non-contiguous fragments on privately owned land, and is used as natural rangelands for sheep grazing. The vegetation, soil chemical parameters, and rhizosphere soil microbial ecology of a dominant plant, Eriocephalus purpureus, were assessed. A combination of field sampling and recording, laboratory analyses of soil samples, and interviews were used to glean data. Data were statistically analysed using multivariate techniques. Overall plant species richness did not differ among the study sites, though plant species richness and cover of the different plant growth form categories varied among the sites. Soil chemical parameters varied among sites. Soil chemical and rhizosphere soil microbial parameters co-varied, and showed different profiles among the study sites. High cover of E. purpureus was associated with high microbial enzyme activity, while high cover of (other, non-dominant) non-succulent shrubs was associated with high bacterial functional diversity. Cover of geophytes, Asparagus capensis and perennial grass was associated with high microbial biomass. The findings indicate that E. purpureus-dominated Niewoudtville Shale Renosterveld is heterogeneous not only in terms of vegetation, but also in terms of soil chemical and microbial parameters. The results support the conservation of all fragments of remaining renosterveld, as they may serve as valuable resources of not only plant genetic material but also of soil microbial communities.
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    The behaviour and feeding ecology of extralimital giraffe within Albany Thicket vegetation in the Little Karoo, South Africa
    (University of the Western Cape, 2018) Paulse, Jamie; Couldridge, Vanessa; Cupido, Clement; Deacon, Francois
    Due to their popularity for tourism, giraffes are being introduced into Thicket areas within the Little Karoo region of the Western Cape. However, information regarding the activity budgets and diet selection of these giraffes is lacking. Therefore, this study aimed to achieve three objectives; to determine the diurnal activity budget, diet composition and browsing levels, and the estimated browsing capacities of extralimital giraffe. The study was conducted on two privately owned farms, namely Kareesbos Private Game Reserve and Tsumkwe Private Game Reserves. Observations were completed on both study sites using the interval scan method, whereby observations were conducted on all visible individuals from 6 am – 6 pm for four days every 3 months (winter, spring, summer and autumn). Observations found browsing to be the most dominant activity displayed by both populations, with walking and rumination being the second and third most dominant activity. Females browsed more than males in both study sites. Dietary observations showed four species (Pappea capensis, Portulacaria afra, Euclea undulata and Searsia longispina) and five species (Searsia longispina, Euclea undulata, Pappea capensis, Vachellia karroo and Grewia robusta) to comprise approximately 90% and 80% of their diet in Kareesbos and Tsumkwe respectively. The importance of flower bearing species (Lycium spp. and Rhigozhum obovatum) increased during the spring and summer seasons in both study sites. In addition to the diet selection, browsing by both giraffe populations was shown to occur mostly below 2 m. Estimated browsing capacities for Kareesbos and Tsumkwe were 25 and 21, and 107 and 88 ha per giraffe, respectively, for the respective browse height strata of less than two metres and five metres. It is suggested that browsing capacities of less than two metres be considered when stocking giraffe and the number of individuals adjusted accordingly on each farm, due to the continuous low browsing of giraffe at less than two metres. Furthermore, results indicate that these giraffes have adapted to take advantage of forage available in ecosystems outside their natural ranges. Low foraging heights suggests possible niche overlap with other browsers, which may result in increased competition for food when it becomes limited. Long term ecological monitoring of extralimital populations and appropriate management procedures are therefore required to avoid the displacement and degradation of indigenous fauna and flora within the Little Karoo, and possible mortalities amongst the giraffe populations.
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    Blood cell histology of Homopus areolatus: effects of season and cohort
    (University of the Western Cape, 2015) Sparks, Sharna; Hofmeyr, Emer. Margaretha D.; Couldridge, Vanessa
    Homopus areolatus is an endemic terrestrial tortoise that resides in a Mediterranean type of climate, which is characterised by winter rainfall and mild winter temperatures. Within ectotherms, such as H. areolatus, physiological changes are elicited by changes in the ambient temperature. These physiological changes are evident in the blood profile of reptiles. I described the morphology of immature and mature erythrocytes, leukocytes as well as thrombocytes of H. areolatus. Additionally, I evaluated erythrocytes, leukocytes and thrombocytes to assess the effects of season and cohort on these cells. Blood samples were collected in 2000 and 2001 at Elandsberg Nature Reserve in the Western Cape from H. areolatus cohorts (female, male, juvenile) in all seasons (spring, summer, autumn, winter). Blood smears were made and stained with modified Giemsa stain. SigmaStat was used for all statistical analysis. Immature erythrocyte types within H. areolatus included basophilic rubricytes, polychromatophilic rubricytes and polychromatophilic erythrocytes. Upon my evaluation, I encountered evidence to suggest that small and large immature erythrocytes possibly developed from two distinctive lineages. Further research is required to discern which lineage gave rise to which immature erythrocyte type. Cohort had no effect upon immature erythrocytes. Erythropoiesis was most prevalent during winter and spring within H. areolatus. Aberrant features of erythrocytes appeared to be more prevalent during autumn, which signified the driest season with limited food and water. Mature erythrocytes play a huge role in oxygen transport and metabolism in individuals. Factors such as size and shape are relevant since small, mature, ellipsoidal erythrocytes transport oxygen more efficiently than large, spherical erythrocytes. In H. areolatus small, mature, ellipsoidal erythrocytes appeared to be most prevalent during spring and summer. During winter however, large, spherical erythrocytes appeared to be most prevalent. Thrombocytes and seven types of leukocytes were observed within H. areolatus, namely heterophils, lymphocytes, eosinophils, basophils, monocytes, plasma cells and azurophils. Among cohort and season heterophils were most prevalent overall, followed by lymphocytes and eosinophils respectively. Basophils, monocytes, plasma cells and azurophils were present but overall, were relatively few. H. areolatus appeared to be healthy, and leukocyte counts as well as its dimensions appeared to be in accordance with other reptilian studies. This study serves as the first baseline haematological reference forH. areolatus. The study forms the second of its kind on South African tortoises, only one other haematological study has been done namely, P. geometricus which is a sympatric species to H. areolatus.
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    Can bio fortified plants accumulate trace elements essential to the growth and development of humans?
    (University of the Western Cape, 2013) Müller, Francuois Lloyd F.; Raitt, Lincoln
    Micronutrient and trace element deficiencies are a problem affecting nearly two billion people globally. The people affected the most by these deficiencies are those living in poor and rural communities in the developing countries and thus cannot always afford the diverse diet as advocated by WHO and the FAO. Millions of these people living in the poor and developing countries die yearly, either directly or indirectly, as a result of micronutrient and trace element deficiencies. Thus, this study aimed to determine the nutrient content (Co, Cr, F, I, Se and V) of various vegetable based food items collected from the Cape Town area in the Western Cape Province of South Africa. This was done to determine which vegetable crops provided the highest concentrations of essential trace elements, and how much they contribute to the daily recommended intake (DRIs) of these trace elements. It also aimed to assess the effects of the addition of the trace elements (Co, Cr, F, I, Se, Si, Sn and V) on seed germination and root growth under controlled conditions in order to calculate their phytotoxicity, and then to biofortify four vegetable crop species, grown in sand culture, with a composite treatment of the trace elements to determine how the addition of these elements will affect the vegetable crops grown under these experimental conditions. From this study, it was shown that trace element content in vegetable crops in the Western Cape Province of South Africa varied between different geographic locations and that certain trace elements were absent from several items collected from some areas. Although some crop species contained sufficient amounts of certain trace elements to satisfy our daily recommended intakes, most of the crops were found to contain insufficient amounts of many of the trace elements to satisfy our needs. Leafy vegetables and tubers were identified as the better vegetable types to biofortify with essential trace elements as they already contain higher concentrations of several of the essential trace elements and should thus be assessed for their effectiveness as crops to be biofortified. When the trace elements were applied directly to cress and lettuce seeds, it was found that all the trace elements, as well as the composite treatments, exerted phytotoxic effects on cress and/or lettuce seeds when applied at high concentrations. Lettuce was found to be more prone to the effects of these elements. Seed germination was strongly inhibited by fluoride, while several elements affected root growth. When fluoride was left out of the composite treatment, phytotoxicity only occurred at high concentrations. The addition of the trace elements at the high concentrations to already established spinach, cabbage, lettuce and turnip plants were found to affect the uptake of several essential plant nutrients, but the concentrations of the elements affected generally remained higher than the concentrations needed for adequate growth of agricultural crops. Several of the trace elements supplied to the plants were also found to be retained in the roots of the vegetable crops however, as the concentrations supplied to the plants increased, so did the concentrations found in the edible portions of the crops. Agronomic biofortification of vegetable crops with simultaneous additions of multiple trace elements, under these experimental conditions, was thus considered to be a viable option to increase the concentrations of essential mineral nutrients in the edible portions of vegetable crops. However, these modified nutrient fertilizers should only be given to established crops or without the addition of fluoride. Further research on a wider variety of seeds and vegetable crops, as well as research under field conditions is needed to determine whether these findings remain relevant under these conditions.
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    Can biofortified plants accumulate trace elements essential to the growth and development of humans?
    (University of the Western Cape, 2013) Müller, Francuois Lloyd; Raitt, Lincoln
    This study aimed to determine the nutrient content (Co, Cr, F, I, Se and V) of various vegetable based food items collected from the Cape Town area in the Western Cape Province of South Africa. This was done to determine which vegetable crops provided the highest concentrations of essential trace elements, and how much they contribute to the daily recommended intake (DRIs) of these trace elements. It also aimed to assess the effects of the addition of the trace elements (Co, Cr, F, I, Se, Si, Sn and V) on seed germination and root growth under controlled conditions in order to calculate their phytotoxicity, and then to biofortify four vegetable crop species, grown in sand culture, with a composite treatment of the trace elements to determine how the addition of these elements will affect the vegetable crops grown under these experimental conditions. From this study, it was shown that trace element content in vegetable crops in the Western Cape Province of South Africa varied between different geographic locations and that certain trace elements were absent from several items collected from some areas. Although some crop species contained sufficient amounts of certain trace elements to satisfy our daily recommended intakes, most of the crops were found to contain insufficient amounts of many of the trace elements to satisfy our needs. Leafy vegetables and tubers were identified as the better vegetable types to biofortify with essential trace elements as they already contain higher concentrations of several of the essential trace elements and should thus be assessed for their effectiveness as crops to be biofortified. When the trace elements were applied directly to cress and lettuce seeds, it was found that all the trace elements, as well as the composite treatments, exerted phytotoxic effects on cress and/or lettuce seeds when applied athighconcentrations. Lettuce was found to be more prone to the effects of these elements. Seed germination was strongly inhibited by fluoride, while several elements affected root growth. When fluoride was left out of the composite treatment, phytotoxicity only occurred at high concentrations. The addition of the trace elements at the high concentrations to already established spinach, cabbage, lettuce and turnip plants were found to affect the uptake of several essential plant nutrients, but the concentrations of the elements affected generally remained higher than the concentrations needed for adequate growth of agricultural crops. Several of the trace elements supplied to the plants were also found to be retained in the roots of the vegetable crops however, as the concentrations supplied to the plants increased, so did the concentrations found in the edible portions of the crops
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    Carbon sequestration in cultivated and uncultivated Vachellia karroo sites in Tankwa Karoo National Park
    (University of Western Cape, 2021) Phophe, Paulina Avhavhudzani; Knight, Richard
    The Succulent Karoo Biome (SKB) in South Africa is widely reputed to house Earth’s greatest diversity of succulent plants. It is also famous for spectacular displays of annual flowers after good rains. The area experiences winter rainfall which infrequently exceeds 100 mm per annum but certain parts of the SKB can get 250 mm. Irrigated agriculture on a large scale was therefore not a viable option when European farmers began colonizing the land. The land was conquered from the indigenous Khoekhoe herders and San hunter-gatherers, South Africa’s first peoples. The biome underwent extreme transformation in the last 200 years following colonisation which resulted in homogenization of the landscape and extinction of many succulents thus reducing biodiversity.
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    Changes in communities of Hydrozoa (Siphonophorae and Hydromedusae) across the Atlantic sector of the Southern Ocean
    (University of the Western Cape, 2020) Kuyper, Drikus; Gibbons, Mark; Thibault, Delphine
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    Characterization of bacterial species in Steinkopf a communal farming area in South Africa: A closer look at pathogenesis
    (University of the Western Cape, 2019) Foster, Jodene; Engelbrecht, Adriaan; Du Plessis, Morné; Taioe, Oriel Moeti
    The human population in sub-Saharan Africa has been increasing due to decreases in mortality rates and increases in average human age; in turn increasing poverty and pressure placed on agriculture and agricultural production. However, livestock production in South Africa, and globally, is declining due to disease and parasite prevalence, lack of feed, poor breeding, marketing management, change in nutrition in both livestock and humans, rapid urbanization, encroachment on wildlife and unfavourable climatic conditions brought about by global change. One unintended consequence has been the emergence and spread of transboundary animal diseases and, more specifically, the resurgence and emergence of zoonotic disease. Zoonotic diseases are sicknesses transmissible from animals to humans, resulting from direct contact or environmental reservoirs. Previous studies have identified small-scale farmers as the group most prevalent to contracting zoonotic diseases, especially those working in a communal dispensation. Therefore, this study focused on the communal farming area of Steinkopf in the semi-arid Namaqualand region of South Africa. Steinkopf is one of the largest Act 9 areas, with communal land tenure and a mixed farming system, sheep and goats, on about 759 ha. Steinkopf is divided into two rainfall regions, the Succulent Karoo (winter rainfall region) and the Nama Karoo (summer rainfall region). This study aims to identify and characterise the bacterial microbial communities found in the topsoil layer and faecal matter (dung) within the winter and summer rainfall regions of Steinkopf communal rangeland using Next-generation sequencing. Further, the aim is to assess whether pathogenic bacteria are present within the rangeland and what their potential impact on the local farming community might be if present. A high-throughput sequencing technique (Next-generation sequencing) was used to amplify 16S rRNA targeting the V3-V4 hypervariable regions. The phylotypes produced were 37 phyla, 353 families and 634 genera of which the most abundant bacterial phyla were Planctomycetes, Firmicutes and Bacteroidetes and the most abundant genera were Gemmata, Akkermansia and Arthrobacter. Alpha diversity indices showed a variation in species diversity, evenness and richness between soil and dung samples, it shows a higher species richness, evenness and unique OTUs detected in summer soil samples and at natural water holes. Through these analysis soil samples were regarded as superior to dung samples within this particular environment and for this particular study. Natural water holes were identified as a safer option when compared to man-made water holes as there are natural systems in place that combat the spread and growth of harmful bacterial microbes. It was found that seasonality has a great impact on the development and growth of environmental bacterial microbiota and that the current randomness of grazing routes and migrations within the Steinkopf communal rangeland is not a detriment but instead acts as a benefits to environmental and livestock health. Furthermore, a total of three pathogenic bacteria were identified however, they occurred at relatively low abundances. It can thus be concluded that this study thoroughly describes the usefulness of using a high-throughput sequencing technique such as Next-generation sequencing when amplifying a small sample size in order to achieve a large volume of information; and that currently the Steinkopf communal rangeland is not subjected to or at risk of a potential zoonotic threat.