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

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A comparative study of degeneration of the posterior limbs and girdles of some scelotes species.
(University of the Western Cape, 1981) Wilson, Brain .A; Skinner, J.H; Leonard, C.J
The genus Scelotes was instituted by Fitzinger in 1826 and is represented by nineteen species and subspecies in Southern Africa (Fitzsimons, 1943) . Valuable contributions have been made to our knowledge of the Lacertilia by pioneers such as Gadow (1881) , Cope (1892) , El-Toubi (1938) , King (1964) and Tiedeman et al . (1975) who investigated the osteology and myology. Essex (1927) , Stokely (1947) , Lande (1978) and Leonard (1979) dealt with the evolution of limb loss and pelvic girdle degeneration in the lizards , and especially in the skinks. van der Klaauw (1948), Snyder (1952; 1954) and Gans (1962; 1966; 1973) studied the ecology and behaviour of limbless tetrapods, while De Witte and Laurent (1943) and Greer (1970) contributed to our knowledge on the systematics of the skinks. Partial or complete loss of limbs and degeneration in the pelvic arch have possibly evolved independently in a variety of tetrapods. The genus Scelotes exhibits a full range of degeneration - from fully pentadactyle tetrapodous forms to limbless species. The question arises : Can a general pattern of devolution be observed in this genus? Al though many of the Scelotes species have already been described, it will here for the first time be attempted to compare the different stages of degeneration as exhibited in this genus. A major objective of this work will , therefore be to analyze the pattern of degeneration in Scelotes. Firstly, the osteology of the pelvic girdle and hindlimbs of the Scelotes species will be described and, secondly, these structures will be compared. Thirdly, an attempt will be made to graphically reflect the major trends associated with limb regression by employing morphometric data obtained from the limited number of specimens available
The roles of intertidal marine gastropod shells as secondary substrate for macroalgae
(University of the Western Cape, 2014) Padua, Courtney Ann; Maneveldt, Gavin W.
Primary space within the marine benthos is by far the most limited resource for which all sessile organisms must compete. It only ever becomes available when the organisms occupying it dies or are forced to leave the area. It has long been established that herbivorous molluscs play an important role in freeing up space on rocky intertidal shores. However, their grazing activities, although freeing up space. often result in diminished species diversity because most intertidal algae and invertebrates are either consumed or displaced. The exploitation of microhabitats (secondary space) therefore becomes important under such scenarios and is known to increase the biodiversity of a particular area. Ironically, mollusc shells are knom1 to provide such microhabitats as they increase the available surface area for the settlement of a variety of epizoic organisms. While the international literature abounds with examples of the importance of mollusc shells as secondary substrata, virtually nothing is known of these associations within a South African context. Surveys were conducted on five more or less equidistant intertidal rocky shore communities (Kalk Bay. Rooiels, Sandbaai, Pearly Beach, Stinkbaai) within the South African western biogeographic transition zone. At all sites, invertebrate densities and biomass, and algal and lichen percent cover abundance were sampled along transect lines running more or less parallel to the shoreline from mean highwater spring (MHWS) tide mark to mean low water spring (MLWS) tide mark.
Reptile community responses to an avian ecosystem engineer
(University of the Western Cape, 2023) Buckley, Emma Elizabeth; Maritz, Bryan
In the Kalahari, sociable weavers (Philetairus socius) build huge, communal nests. Although Kalahari tree skinks (Trachylepis spilogaster) are known to preferentially use trees that host such colonies, the degree to which other reptile species use these trees is not well documented. Sociable weaver nests can provide benefits to different animals and can provide food and shelter for reptiles. I trapped reptiles at Tswalu Kalahari Reserve to assess the impact of sociable weaver colonies on selected reptile populations during weaver breeding and non-breeding seasons. I tested the hypothesis that the reptile community under trees with colonies would differ in diversity compared to those at nearby control trees without colonies, because the sociable weaver colonies provide more resources (food and shelter) to the reptiles than trees without colonies. I also tested whether the abundance of the Kalahari tree skink, Cape cobra (Naja nivea), and Cape thick-toed gecko (Pachydactylus capensis) under trees with colonies differed from those at nearby control trees without colonies, as these were the most abundant species found at the sociable weaver nests. Trapping for 11 days at 24 sites (12 colony trees, 12 control trees), on two occasions, once in March when weavers were breeding, and once in September before they were breeding, resulted in 665 total detections of 13 reptile species, including 148 total recaptures. Mean species richness was significantly higher at colony trees than at control trees during both surveys (2.5 times higher when the birds were breeding; 1.6 times higher when the birds were not breeding). Poisson N-mixture modelling revealed that Kalahari tree skink was significantly more abundant on colony trees during the breeding (3.2 times) and non-breeding seasons (3.7 times).
Temporal and spatial variability in copepod abundance, distribution and community structure off Walvis Bay in the northern Benguela Current, 1979-1981
(University of the Western Cape, 2005) Tsotsobe, Sakhile Vincent; Gibbons, M.J; Verheye, H.M
The zooplankton samples used for retrospective analysis in this study form part of the historical SWAPELS (South West African Pelagic Egg and Larva Survey) collection from January 1972 to December 1989, which covered the entire Namibian shelf. The SWAPELS Programme was initiated following the collapse of the Namibian sardine fishery during the late 1960s and early 1970s. This study investigates variability in the temporal and spatial distribution of total zooplankton (non-gelatinous) biomass, total copepod abundance, as well as copepod community structure off the coast of Walvis Bay along, primarily, transect 70 (23° S), and secondarily, transects 66 (22°67 S) and 74 (23°33 S), over the period 1979- 1981. Included in the data set are sea surface temperatures (SSTs) and surface salinities, allowing for spatio-temporal trends in the hydrology of this region to be examined. Despite extensive variability in SST (1 1.27- 18.15 °C), the most frequently occurring SSTs were in the 15-16 °C range. In 1979 salinities ranged mostly between 35.1 and 35.2, whereas in 1980 and 1981 modal salinities fell within the 35.0-35.1 and 35.2- 35.3 ranges, respectively. A clear seasonal pattern in the cross-shelf distribution of SST and salinity was observed in 1979-80, when, generally, warm , high-salinity water covered most of transect 70 (23° S) in summer to early autumn. In spring the cool inshore water extended seaward, to recede again into summer. The existence of cool inshore surface water from mid-winter to mid-spring, warming up into summer and extending offshore, was indicative of a typical upwelling cycle off Walvis Bay.
The reproductive physiology of The south african pilchard.
(UWC, 1995) Leaner, JJ
Epipelagic fish species form an integral component of the world's supply of protein. The most abundant of these fish belong to the order Clupeiformes (clupeoids) which include sardine, pilchard, sardinella, sprat, and herring. This multi-species group has been estimated to have contributed up to 20% of the world's marine catch in the 1980's (Armstrong and Thomas, 1989). The economic importance of the clupeoids was not only realized by the world's commercial pelagic fishing industry, but the energy was soon directed into experimental research on the multi-species group, both locally and internationally.
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).
Species delimitation and assessment of genetic variability in Carpobrotus (Aizoaceae): evidence from amplified fragment length polymorphisms
(University of the Western Cape, 2004) Khunou, Angeline; Reeves, Gail
During the course of this thesis, AFLP technique was successfully applied to the Aizoaceae taxa. This study involved a substantial component of laboratory work including generating and analysing AFLP data, the operation of an ABI377 automated DNA sequencer, and use of GeneScan and Genotyper software (Applied Biosystems). The initial motivation for this study was to reconstruct relationships between species of the genus Carpobrotus. However, it soon became clear that this would be impossible via the use of DNA sequence data. This was due to the inability to find DNA regions with sufficient variable characters for phylogenetic reconstruction. Therefore applying the AFLP fingerprinting technique to the question of species-level relationships in Carpobrotus resulted in individuals of the same species not forming distinct groups. This has subsequently led to the conclusion that gene flow is common across species boundaries in Carpobrotus as a result of hybridisation. An alternative ved may be that current species delimitations in this group are not well defined. These results also concord well with isozyme studies taxa in the Mediterranean Basin. Increased sampling of species other than C. acinaciformis and C. edulis would allow further investigation into the genetic delimitation and affinities of Carpobrotus, and shed light on the In the biotechnological age the use of molecular techniques has has the potential to greatly improve the bio-prospecting process. This has particular relevance to plants with medicinal properties, such as Carpobrotus, whereby targeted selection of genotypes with well-characterised medicinal properties may increase efficiency. Genetic and phylogenetic information can also help to identify closely related species and genera that may share similar metabolic pathways and properties. These issues are quickly coming to the forefront in the new South Africa, with the opening up of traditional knowledge systems, and subsequent integration and contact with the biotechnology community. 79
Genetic analysis of resistance to powdery mildew (podosphaeara leucotricha) in apple (Malus x dornestica Borkh.)
(University of the Western Cape, 2008) Simayi, Zolani Ellias; Rees, Jasper G.
Apple powdery mildew, caused by Podosphaera leucotricha, is one of the major diseases of the cultivated apple in the Western Cape, causing severe losses in yield and affecting fruit quality. This affects the deciduous fruit industry as costs are incurred on the management of this disease. The application of fungicides is one of the strategies mostly used to control the spread of the pathogen. Since consumers demand high quality fruit with no harmful chemical residues, alternative approaches that minimize the reliance on agri-chemicals for the control of this disease must be developed. Marker-assisted breeding for the development of new varieties that exhibit durable resistance to the fungus is the best and safest way to reduce damage caused by powdery mildew.
Studies of foraminifera associated with gelidium pristoides (turner) keutzing (gelidiales: rhodophyta)
(University of the Western Cape, 2002) Toefy, R; McMillan, K; Gibbons, M.J
Our understanding of the macrofauna of hard intertidal substrata around South Africa is fairly comprehensive, and we have a good understanding of the environmental factors responsible for structuring macrofaunal communities (McQuaid & Branch, 1985; Bustamante et al., 1996; Emanuel et al., 1992). The same cannot be said for meiofaunal communities of rocky shores, which despite their neglect are known to play an important role in the functioning of many intertidal systems (Gibbons & Griffiths, 1986). While macrofauna may dominate rocky shores in terms of biomass, meiofauna are generally more abundant, and because they have faster turnover rates they make an important contribution to secondary production (Gibbons & Griffiths, 1986).
Specias delimitation and assessment of genetic variability in Carpobrotus (Alzoaceae): evidence from amplified fragment length polymorphisms
(University of the Western Cape, 2004) Khunou, Angeline; Reeves, Gail; Weitz, Frans
Species of Carpobrotus (Aizoaceae: Ruschioideae) are widely spread throughout South Africa and are commonly used for their medicinal properties. The genus consists of 13 species of which seven occur in South Africa, five in Australia and one in Chile. A number of investigations on South African species have demonstrated that some taxa exhibit anti-microbial activity. Using AFLPs (amplified fragment length polymorphisms) this study was undertaken with the primary aim of resolving relationships between Carpobrotus species in South Africa, and determining species limits by assessing their genetic distinctness. In addition, levels of genetic variability among populations of two South African species, C. acinaciformis and C. edulis werc assessed in more detail. AFLPs were not able to resolve conflict surrounding species boundaries, perhaps due to extensive hybridization. However, major groupings within South African species were identified, although no geographical structuring of these populations was evident. From a bio-prospecting perspective caution needs to be taken when sampling Carpobrotus due to difficulty in identifying species possibly as a result of hybridization.
The distribution of the desert rain frog ( Breviceps macrops) in South Africa
(University of the Western Cape, 2009) Bell, Kirsty Jane; Channing, Alan
The desert rain frog (Breviceps macrops) is an arid adapted anuran found on the west coast of southern Africa occurring within the Sandveld of the Succulent Karoo Biome. It is associated with white aeolian sand deposits, sparse desert vegetation and coastal fog. Little is known of its behaviour and life history strategy. Its distribution is recognised in the Atlas and Red Data Book of the Frogs of South Africa, Lesotho, and Swaziland as stretching from Koiingnaas in the South to Luderitz in the North and 10 km inland. This distribution has been called into question due to misidentification and ambiguous historical records. This study examines the distribution of B. macrops in order to clarify these discrepancies and found that its distribution does not stretch beyond 2 km south of the town of Kleinzee nor further than 6 km inland throughout its range in South Africa. The reasons for this are not clear, as there appears to be adequate habitat south of this point. Habitat suitability, food availability and competition, anthropogenic disturbance, and historical distribution patterns are discussed in terms of their impact on B. macrops distribution however no significant correlations are found. In addition, examination of the available habitat within South Africa reveals that the anthropogenic impact of strip mining for alluvial diamonds has greatly transformed much of the west coast of southern Africa including vast tracts of B. macrops habitat. Previous estimates of distribution as pertains to available habitat are found to be overly generous and this study estimates that only 2l.84Vo of the original area remains. Thus the conservation status of this species is dire and should be reviewed by the IUCN in light of current findings. It is the assertion of the author that the current status of Vulnerable (VU) be elevated to Endangered (EN).
Food resources available to juvenile fish (particularly rhabdosargus holubi) in seagrass beds of the swartkops etuary
(University of the Western Cape, 2023) Brown, Kylen Leigh; Rajkaran, Anusha
Estuarine habitats are critical nursery areas for many species of marine fishes during their early life stages in terms of food availability and structural complexity, which increases survival and growth rates. The Cape stumpnose Rhabdosargus holubi is one of the most abundant marine fish species found in estuaries along the south-east coast and depends on estuaries as exclusive nursery habitats. This study aimed to identify the epiphytic diatom and macrofauna food resources available to R. holubi in the seagrass Zostera capensis habitat of the Swartkops Estuary. This habitat has been identified as a core nursery area for this species through a combination of greater abundance, higher growth and survival of juveniles. This study compared what was found in the seagrass habitat and assessed whether this habitat provided for the prey resources most commonly observed in the diet of R. holub.
Understanding mangrove dynamics in range edge populations in South Africa
(University of the Western Cape, 2023) ZIde, Ayanda; Rajkaran, Anusha
Mangrove distribution along the East African region occurs from Somalia to South Africa, including Madagascar and other islands. It comprises approximately 10 species, including Avicennia marina (Forsk.) Vierh, Bruguiera gymnorrhiza (L.) Lam. and Rhizophora mucronata Lam. that are core mangrove species and common in the region. Within the Indo-West Pacific (IWP) Province, studies have determined the genetic variation of mangrove species, but only a limited number of studies have included B. gymnorrhiza and R. mucronata populations occurring in the East African region, while none have included those occurring in South Africa. Genetic variation and environmental conditions affect plant performance and the longevity of mangrove populations.
Detection of phycotoxins along the South African coast: a comparison of three different biological assay systems and instrumental analysis by high performance liquid chromatography
(University of the Western Cape, 1998) Myburgh, Carolyn l.; Gibbons, Mark
In recent years, harmful algal blooms have been of growing concern in many parts of the world. These blooms often result in deterioration in water quality, large-scale mortalities in marine life, and shellfish poisonings which can adversely affect local mariculture industries, coastal tourism and fisheries. Because of problems related to some of the methods that are currently used to detect phycotoxins (e.g. false positives), it has become necessary to explore new approaches, especially for routine monitoring. In this study, High Performnance Liquid Chromatography was used as an instrumental method for detecting Paralytic Shellfish Poisoning in mussel samples. Three bioassays were also examined, viz. the luminescent bacteria assay (LUMIStox kit), the Artemia larvae assay (Artox kit), and the sea urchin gamete test. The bioassays were assessed as to their suitability, reliability and practicality in detecting phycotoxins in water and mussel samples. HPLC was used to establish toxin profiles of mussel samples from South Africa, where Alemndrium catenella was present in the water. The three bioassays were found to be unsuitable for detection of toxins in mussel samples. However, based on the results obtained in this study, the Artox kit seems to be the most suitable, sensitive and practical bioassay for the detection of PSP toxins in water samples.
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.
Investigating the relationship between novel farming practices and zoonotic disease transmission at the wildlife/livestock interface: A case study at a commercial farm and conservancy in Beaufort West, South Africa
(University of the Western Cape, 2022) Badrodien, Yameen; Engelbrecht, Adriaan
In recent years, the intensification of agricultural activities in South Africa, has led to many of the sectors farmers adopting novel farming practices as a means of promoting economic productivity. One such practice, is the expansion of traditional livestock systems to include unconventional forms of stock such as wildlife. Despite the economic benefits of this approach, the threat of disease re/emergence remains a major obstacle, as both wild and domesticated animals are known reservoirs to a variety of disease-causing agents. Whilst many studies have directed their attention toward the surveillance of emerging pathogens within animal populations, less attention has been directed towards monitoring pathogens within environmental disease reservoirs (i.e., soil), which may be affected by these novel farming practices.
Phylogeography and co-evolution of ectoparasitic mites that live on the rodent host species Lemniscomys rosalia (Rodentia: Muridea)
(University of the Western Cape, 2022) Meissenheimer, Keenan Keith; Engelbrecht, Adriaan
Lemniscomys rosalia is a widespread, possibly cryptic species of murid grass mouse. Cytogenetic evidence points towards cryptic speciation in L. rosalia as the eastern African karyotype (2N = 54; FNA = 62) differs from the southern African karyotype (2N = 48; FNA = 62). Further resolution through phylogeographic analysis is necessary to corroborate this hypothesis; however, there is little to no molecular data on L. rosalia. The present study sought to determine the phylogeographic patterns found in southern African populations of L. rosalia using mitochondrial and nuclear markers. Parasites are commonly used to complement the genealogy of their host species since both species may undergo co-phylogeny.
Description and assessment of neuston 1 communities present in the South Indian Ocean
(University of the Western Cape, 2022) Parker, Yasmeen; Gibbons, Mark
Animal communities living at the sea-surface are relatively poorly known, despite the fact that this biotope is globally distributed, it acts as an important nursery area for many commercially important taxa and supports significant amounts of anthropogenic waste. This lack of knowledge applies particularly to the Indian Ocean. Here, I describe the structure of non-copepod neuston assemblages across the Southern Indian Ocean Gyre using samples collected between 26 June – 16 July 2015 from 35 stations along a transect line at 20° S. Neuston was sampled using triplicated manta trawls at each station, while environmental parameters were assessed using a CDT. All non-copepod neuston were identified to morphospecies, with the exception of siphonophores, which were identified to species.
Using faecal DNA to investigate the diet of the snakes, Psammophis crucifer and Psammophylax rhombeatus
(University of the Western Cape, 2022) Scholtz, Kim Jennilee; Maritz, Bryan
Knowledge of the feeding ecology of an organism helps us to better understand predator-prey relationships and aspects of species biology, ecology and life-history traits. Understanding the feeding ecologies of snakes is challenging because snakes are generally secretive and often difficult to observe when foraging in the wild. Traditionally, studies attempting to quantify the diets of snakes relied on observing direct predation events, dissecting dead specimens, or microscopy of gut and stomach contents to identify prey species. However, investigations using traditional methods can result in an incomplete understanding of prey utilised by particular snakes. Analysis of prey DNA in snake faeces is a useful method to obtain accurate information on diet.
Systematics of subtribe Anthosperminae and the generic affinities of Anthospermum and Nenax (Rubiaceae: Anthospermeae)
(University of Western Cape, 2021) Nemando, Rangani; Boatwright, James
The last taxonomic treatment of the subtribe Anthosperminae was in 1986 by Puff., nevertheless, few attempts have been made to resolve the phylogeny and the inter- and infrageneric relationships within the subtribe. The genera Anthospermum L. (39 species) and Nenax Gaertn. (11 species) are considered the most difficult groups to distinguish. Anthospermum species are widely distributed in Sub-Saharaan Africa and Madagascar with the highest concentration of taxa in southern Africa, while Nenax species are restricted in southern Africa, south-western Cape Floristic Region. The two genera share common morphological and anatomical characters.

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