The fish populations in small southern African reservoirs are largely unexploited and there is potential for fisheries development. However, the development of sustainable fisheries requires reliable estimates of potential yield or production. Empirical models that have been developed to predict fish production only apply to large water bodies and only predict total fish production, not the production of individual species. Small reservoirs generally have few commercially important species and therefore species-specific fish production models are an alternative approach. The small reservoirs of the Eastern Cape are dominated by the moggel (Labeo umbratus). The principal objectives of this thesis were to gain an understanding of the ecology of small reservoirs and the function of moggel in these systems. This information was used to design a research approach to rapidly develop species-specific models for small reservoirs in southern Africa. The limnology of two small reservoirs was compared. During the study period the reservoirs were turbid and showed a warm, monomictic pattern of thermal stratification. Anthropogenic pressure in the reservoir catchments appeared to be the overriding factor increasing the nutrient input to the reservoirs and consequently, influencing the biomass of algae in the reservoirs. The feeding biology of moggel in Katriver and Laing reservoirs was examined. Moggel are detrivorous and successfully digested diatoms. The slower growth rate of moggel in Katriver reservoir was attributed to the poorer nutritional value of the diet as a consequence of the lower concentration of diatoms in the detrital aggregate. The reproductive characteristics of moggel were examined in four reservoirs. Moggel were able to reproduce successfully in the reservoirs. This could be attributed to their r-selected reproductive strategy, with a high fecundity and an extended spawning season and their ability to spawn in a floodplain environment. Differences in recruitment success between years were found to be a consequence of the timing and duration of seasonal rains. The number of mature females in a population and the availability of suitable spawning habitat influenced recruitment success. The life history of the moggel in five reservoirs was compared. Growth appeared to be related to food availability, while mortality was lower in the populations where food was abundant and there were less predatory species. Size and age at maturity were not affected by environmental factors, but were dependent on growth and mortality. Three contrasting methods were used to estimate moggel gillnet selectivity. The Sechin, direct fyke net method and length-structured model all yielded similar results and correction factors obtained from the selectivity study were applied to the gillnet data to estimate the fish population size and structure in each reservoir. Using information from the life history and selectivity studies, the biomass and production of five moggel populations was estimated and related to abiotic and biotic factors in the reservoirs and their catchments. Moggel biomass and production was dependent on the biomass of algae, which was dependent on morphoedaphic characteristics of the reservoirs. Small, shallow reservoirs with a reasonable amount of human habitation in their catchments would sustain the highest algal biomass and provided they had adequate spawning habitat would also have the highest moggel biomass and production. The future research requirements for small reservoir fisheries are outlined and include a three-year program to develop a species-specific production model for any of the dominant species.

With our contemporary biota under increasing threat of extinction, it is of interest to understand where, why and how biological diversity is generated. If focussed on appropriate taxa, phylogeographic and phylogenetic studies can assist in the identification of both places and processes central to the origin and maintenance of biological diversity. It is explained why southern Africa presents a perfect test-bed for exploring such mechanisms of diversification and why cicadas (Hemiptera: Cicadidae) have proved very suitable tools for studies of historical biogeography. This study then exemplifies these points by providing the first large-scale investigation of the historical biogeography of the tribe Platypleurini Schmidt, 1918, with emphasis on the genus Platypleura Amyot & Seville, 1843 in southern Africa. Standard methods of DNA sequencing provided data from portions of the mitochondrial small subunit ribosomal 16S RNA (16S) and cytochrome oxidase subunits I (COI) and II (COII); and the nuclear elongation factor 1 alpha (EF-1α) from 400 ethanol-preserved specimens. These data were analysed using standard phylogenetic methods and a time scale of diversification was estimated using a Bayesian framework and both fossil data and DNA substitution rates. The results showed that the tribe is too recent to be of Gondwanan origin. The lack of monophyly of the genera represented in both Asia and Africa showed that the tribe needs formal taxonomic revision. Diversification of the African platypleurine genera coincides with aridification in the early Oligocene. Dispersal of Asian platypleurine taxa coincides with the meeting of Africa and Eurasia in the mid-Oligocene. Two radiations within African Platypleura are hypothesised; one distributed over most of sub-Saharan Africa and the second restricted to southern Africa, with clades restricted within regional biomes. Within each of the three focal biomes, cryptic taxonomic diversity was confirmed, suggesting that, even in relatively well understood groups such as the southern African platypleurine cicadas, molecular data can identify further diversity. Although each focal taxon was restricted to non-overlapping biomes, comparison of the three biomes highlighted interactions between palaeoclimates and fixed landscape features (coastal topography, river catchments and escarpments) as causative agents of vicariance, dispersal, extinction and diversification of these volant insects. The results of using co-distributed species for comparative study cautions against making inferences based on single-taxon datasets and highlights the need to use many, evolutionarily independent taxa when identifying mechanisms of diversification. The dating analyses imply that within-species lineage diversification occurred overwhelmingly within the Pleistocene, a trend that is being increasingly recognised in print for other biota. Some caveats about using phylogenetic approaches to estimate ancestral areas are illustrated. Several recommendations are made regarding additional taxa and data sources for understanding the origin and maintenance of biological diversity.

To date the SADC region has managed to develop a manufacturing base but this base is still small as evidenced by its low contribution to GDP. For example, only three out of the fourteen SADC countries, viz. Mauritius, South Africa and Swaziland, had over 20 percent of their GDP originating from the manufacturing sector throughout the 1990s. Also to note is that while the manufacturing sector is quite diversified, the sector is dominated by industrial processes which are more of resource and labour-intensive in nature than those processes of scale-intensive, differentiated and science based in nature. TIle trade performance of the manufacturing sector supports these observations and as such the region is heavily dependent on imports for scale-intensive, differentiated and science based commodities. However, despite the fact that the region tends to focus more on resource- and labour-intensive manufacturing activities, products from these manufacturing activities are still significant components of manufactured goods imports into the region. Also to note is that since resource- and labour-intensive industries dominate manufacturing activities; these are the areas in which investment opportunities abound. For example, agro-based manufacturing presents most of the investment opportunities, with food processing presenting the majority of the investment opportunities followed by garments and textiles production. Mineral processing also presents significant investment opportunities. The analyses of the nature of the manufacturing sector also show that in a few SADC countries, viz. Mauritius, South Africa and Zimbabwe; scale-intensive, differentiated and science based industries also form a significant component of the industrial base implying more technologically complex manufacturing sectors. Since high technology and technologically complex manufacturing activities are limited, investment opportunities in these manufacturing sub-sectors are also limited to just a few countries However, with the SADC ITA in place, opportunities could arise for these limited technology-related manufacturing facilities to expand or engage in import substitution production so as to meet the demands of the growing regional market. It is also important to note that, while the region may not have as competitive advantage in these industries as in the resource- and labour-intensive industries, there is a need for the region to selectively identify and target such industries for priority development, a lesson SADC could learn from the East Asian NIC's took in their industrialisation strategy. The study also shows that the manufacturing sector has been a priority sector for both domestic and foreign investors. This has implications for industrial development because a strong and dynamic manufacturing sector would be developed, forming a sound basis for industrialisation as well as being able to effectively link and support all the other sectors of the economy. FDI could help the region to fully utilise the labour-intensive industries and use them as a stepping-stone to higher levels of industrial development. This is a lesson to SADC from the experiences of the East Asian NICs where while industrialisation was initiated by labour-intensive manufacturing, the countries were able to move into capital-intensive manufacturing due to FDI as it enabled the establishment of the industrial bases, thus leading to a rise in the share of manufactured exports. FDI could also help to develop the resource-intensive industries further by promoting further processing of raw materials into products of more value, thus propelling industrialisation through a resource-led industrial development programme as the current resource-intensive industries become fully utilised. The raw materials which occur in great abundance in the region's primary sector would have a ready market in the manufacturing sector where they would serve as inputs to the production of high value products. The currently smaller industrial base for scale-intensive products, differentiated and science-based manufactured products would benefit from the improved technological capabilities and managerial skills that result from FDI. Therefore, by impacting positively on manufacturing activities of both low and high MVA, FDI would thus have a facilitating role in establishing a more solid industrial base, broadening the current manufacturing base, and improving installed capacity utilisation. The study also shows that investment in productive capacity in the form of machinery and equipment is of great importance in the sampled SADC countries. Investment towards the acquisition of this capital is very important as this is directly relevant towards improving productive capacity. FDI could thus play a facilitating role by augmenting the current domestic investment in machinery and equipment. While the manufacturing sector within the region is still small and the current utilisation of installed industrial capacity is low, there is potential for further industrial growth. The current process to usher in the SADC Free Trade Area would have a facilitating role through various ways: viz. increasing the market size and enabling easier access through the reduction of tariff and non-tariff barriers, promoting regional competitiveness, improved utilisation of regional corridors, increasing opportunities for utilising identified intra-industry trade potentials, and providing opportunities for increased regional cross-border investment. Apart from the SADC FTA, the USA African Growth and Opportunity Act (AGOA) and the Cotonou Agreement will also motivate the identification and utilisation of existing and new potentials within the manufacturing sector in SADC. In order to improve the current nature of industries in the region, there is also a need to design and implement appropriate industrial policies and strategies. Such policies should consider the region's trade policies and the recently launched Regional Indicative Strategic Development Plan (RISDP) so as to complement them. The industrial policies should also address issues relating to industrial investment, technology and local technological capabilities development, human resources development, the structure and nature of industry, the competitiveness of industries, as well as facilitating the complementarities between the agricultural and manufacturing sectors. To this end therefore, instead of relying solely on individual national industrial policies, SADC is in the process of formulating a regional industrial policy and strategies which seek to promote and support sustainable industrial growth across the region, thus facilitating industrial development.

Climatic envelope models focus on the climatic variables affecting species or species assemblages, and are important tools to investigate the effect of climate change on their geographical ranges. These models have largely been proposed in order to make successful predictions on species‘ persistence, determining which variables are likely to induce range expansion, contraction, or shifting. More recent models, including the ability and the cost for individuals to respond promptly to an environmental stimulus, have revealed that species may express phenotypic plasticity able to induce adaptation to the new environment. Consequently, understanding how species evolve to a changing climate is fundamental. From this perspective, investigating intraspecific responses to an environmental variable may contribute to better understanding and prediction of the effect of climate change on the geographical range and evolution of species, particularly in the case of widespread species. In this context, the present study aimed at establishing how environmental variables (focussing mainly on temperature) may have contributed to shape the spatial distribution, physiology, reproductive biology and connectivity of two species of Southern African sandhoppers (Talorchestia capensis and Africorchestia quadrispinosa, Amphipoda, Talitridae). Most of the work was carried out on T. capensis, due to its widespread spatial distribution. A first investigation of the biogeography of T. capensis and A. quadrispinosa, revealed that, for both species, spatial patterns of abundance, size and sex ratio were not explained by the Abundant Centre Hypothesis (greater abundance at the core of a spatial range), but rather guided by bio-physical forces. Precisely, the abundance of sandhoppers was driven by the morphodynamic state of the beach, salinity and temperatures, with strong differentiation among sites that reflected local environmental conditions. In support of these findings, strong population structure in the genetics of T. capensis was found (three main groups) when investigating its phylogeography and genetic connectivity. Although such defined structure may suggests cryptic speciation, the concomitant within-population variation in the COX1 region of mtDNA, also highlighted the importance of individual genetic variability. High individual variability was also found in the response of T. capensis to temperature, both in its physiology (thermal plasticity) and its reproductive biology (maternal effects). Since temperature is one of the main variables affecting the coastal marine systems of southern Africa and the metabolism of animals in general, its effect on the physiology and reproduction of T. capensis was therefore investigated. Thermal responses to increasing/decreasing temperatures were assessed for separated populations of T. capensis. Individual variability was reported in the oxygen consumption of T. capensis in response to temperature (high variation around the means, especially for increasing temperatures). Among population differences in thermal sensitivity were significantly correlated with air temperature variability experienced over the past 23 years, highlighting the importance of historical temperature fluctuations to the current thermal physiology of these sandhoppers. Temperature also had an important effect on the reproductive plasticity of T. capensis. Different temperatures induced mothers to adjust the size of their offspring (i.e. egg size), with larger eggs produced at lower temperatures. Interestingly, females showed strongly significant among individual variation in the size of the eggs. Given the importance of understanding rapid responses of organisms to climate change and considering the fundamental role played by phenotypic plasticity in evolution, the overall study revealed the significance of individual plasticity and variability in response to the environment and highlighted its importance. Particularly, studying the thermal physiology of separated populations and understanding within population reproductive plasticity in response to temperature, helped to clarify how differences among individual responses have important consequences at the population level, possibly explaining the widespread distribution of T. capensis.

The objective of this research was to examine how SADC states can attain goal 8 of the Millennium Development Goals set up by the international community through the United Nations in the year 2000, using trade under the mechanism envisaged by the World Trade Organization by the target date of 2015.

M.Comm. / Since the late 1980's / early 1990's Southern Africa has undergone radical political change. Political democratisation and liberalisation impacted on the economies of individual states as well as on economic relations between states in the region. The democratisation process in South Africa in particular, changed the economic power configurations of the region. South Africa opted to become a member of the SADC in 1994 after its first "representative" elections. The country was initially confronted by unrealistic expectations among the other members in the region regarding the contribution that they expected to emanate from this move. South Africa on the other hand was confronted with the realities of its own reconstruction and development needs. The question that had to be answered however, is how economic integration could contribute to the growth and development of the Southern African region. Of particular interest is the role that external forces could/would have on the integration process. This is the central theme of this document.

School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, 2017 / Snakes have often been proposed as ideal model organisms for studying digestive physiology. This is due to their easily–measureable and extreme changes in their digestive tracts in response to feeding, when compared to other vertebrates. Some species display extreme physiology regulation in response to feeding, a system known as digestive down-regulation. This regulation allows them to down-regulate their digestive tracts during their long fasting periods, which allows them to save energy. In response to feeding, they up-regulate their digestive tracts to a functional level, resulting in a significant increase in the size of the digestive organs during digestion. These changes have been found to be most noticeable in certain ambush foraging snakes. In contrast, actively foraging snakes appear to not display as extreme changes in response to feeding and keep their digestive tracts in a constant state of readiness. However it is not known if this pattern exists in all species and previous methods of classifying the digestive physiology have proven to be expensive, difficult and time consuming. My study aimed to investigate if museum specimens could be used as a cheap and quick method of classifying the characteristics of the digestive physiology within a species. I measured the dimensions of several organs from museum specimens from 13 species of southern African snakes, as well as recorded the relative size of the meal and month of capture. I compared measurements between postprandial and fasting individuals from each species as well as between individuals from each species with the same feeding state to assess whether they were able to down-regulate their digestive systems when not digesting. While the different foraging strategies appeared to be linked to differences in organ morphology, the presence of down-regulation was not clear-cut. No significant differences in organ size between feeding states were found within each species, and very few significant differences were found between species. Few correlations with organ size to meal size or seasonality were found. This suggests that the museum specimens are not suitable for determining digestive physiology in snakes, probably due to the poor quality of the specimens. I therefore recommend the use of freshly obtained samples as a suitable comparison rather than the use of museum specimens. / MT2017

Thesis submitted to the Faculty of Science at the University of the Witwatersrand, Johannesburg in fulfillment of the requirements for the Degree of Doctor of Philosophy. / The taxonomy of modern and fossil Hystricidae and the evolutionary history of the family has been reviewed, with particular reference to 203 undescribed South African specimens from the Transvaal australopithecine deposits and Cave of Hearths. After comparison with all contemporaneous fossil forms (only 10 of the 28 described fossil species seem valid) it was concluded that Xenohystrix crassidens Greenwood 1955, Hystrix makapanensis (Greenwood 1958) and H. africaeaustralis Peters 1852 are present at Hakapansgat Limeworks, whereas only the latter species is present at the remaining australopithecine sites, with the possible exception of a few tentatively referred specimens of H. makapanensis. There are insufficient grounds for erecting a distinct species for the fossil form of H. africaeaustralis present in the australopithecine deposits and the Cave of Hearths material is likewise referred to the modern species. The distribution and minimum numbers of individuals of porcupine species present in the different breccias of the five sites is detailed and a reconstruction of the skull and mandible of X. crassidens attempted. The environment, stratigraphy and potential ages of the source deposits is discussed; it is concluded that with the exception of Taung, the dates suggested by Partridge and Vrba agree with the limited evidence provided by the fossil Hystricidae. Numerous skull characters used in the diagnoses of new Hystrix were examined for variability within a single modern species (only 3 of the 77 extant species proved to be valid) and then tested for diagnostic significance by comparison with the remaining valid species. Special attention was paid to mandibular and dental characters, particularly the crown enamel pattern, but the only reliable diagnostic characters were found to be associated with the anterior part of the cranium, which is seldom preserved in fossil form. The sequence of tooth replacement, a method for identifying isolated teeth, methods for segregating specimens into growth stages, and a standard terminology have been outlined. A taphonomic study, attempting to determine the extent to which fossil porcupines may have been responsible for the accumulation of the Makapansgat Limeworks bone assemblage and for the manufacture of the bone tools described by Dart, was undertaken. Unlike the fossil assemblage porcupine bone accumulations are characterized by a high percentage of much-gnawed bones, a large average fragment size, a high proportion of intact shafts with the concomitant near-absence of bone flakes anci a low survival potential for the articular ends of all limb bones. Comparison showed that the damage done by porcupines differs from that evident on the corresponding skeletal elements from Makapansgat. It is concluded that fossil porcupines had very little to do with either the accumulation or fracture of the Makapansgat Limeworks bones. / Andrew Chakane 2018

Thesis (MTech (Business))--Peninsula Technikon, 2002. / Word processed copy. Summary in English. Includes bibliographical references (leaves 106-108). Also available online.

The objective of this dissertation is to examine the effect of recent trade policy changes on trade and economic growth for southern Africa. This is accomplished by using a dynamic panel data modeling approach to examine the effect of openness on economic growth during the 1990s. The gravity model and Tobit maximum likelihood estimation are used to examine the effect of trade policy changes and two types of spatial separation on the likelihood of trade. The two types of spatial separation are distance and preferential trading arrangements. This study uses sophisticated econometric techniques and a more complete sample of countries than previous studies on southern Africa. / The results show that distance impedes the likelihood of trade. Trade policy changes and the preferential trading arrangements, SADC and COMESA, enhanced trade in southern Africa during the 1990s. The trade stimulating effect was larger for SADC membership. However, some members benefited much more from the existence of preferential relations than other members. The study results indicate that openness affects economic growth.