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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The effect of vegetation on the behaviour and movements of Burchell’s Zebra, Equus burchelli (Gray 1824) in the Telperion Nature Reserve, Mpumalanga, South Africa

Coetzee, Charleen 07 November 2012 (has links)
Telperion is a portion of the eZemvelo Nature Reserve, located in Mpumalanga Province of South Africa. It falls within the Grassland Biome that comprise of a wide diversity of habitats and of which only 2.3% is currently conserved in reserves. The objective of this study was to determine the interaction of Telperion zebras with their vegetation habitats, the influence of vegetation on their movement and how it differs seasonally, focusing specifically on two groups in distinctly different habitat types. The first, Rocky Highveld Grassland, the second a Mixed Grassland community. Hourly zebra observations took place distinguishing between stallions, mares and foals during different times of the day, throughout a year. Zebra habitat was thereby identified and vegetation surveys were conducted in each of these sites according to the Braun-Blanquet vegetation sampling method. The plant species recorded for each sample plot were captured in the vegetation database TURBOVEG. The database was exported into the working directory JUICE. The results indicate no difference between feeding rates of the habitat types. Mares spent most time feeding, then stallions followed by foals, all of which were highest during afternoons. A vegetation gradient was identified, implying that zebras utilise both vegetation communities, as well as the transition between the communities. Zebras were less vigilant during grazing when large numbers were gathered in the same area. Tracking zebras revealed their migrating behaviour from a central point to the rest of the reserve in summer and more specifically to rocky ridges in winter. The understanding of zebra behaviour contributes to management and mitigation for good veld conditions in Telperion. Copyright / Dissertation (MSc)--University of Pretoria, 2012. / Plant Science / unrestricted
2

Risk analysis and potential implications of exotic Gyrodactylus species on cultured and wild cyprinids in the Western Cape, South Africa

Maseng, Monique Rochelle January 2010 (has links)
<p>Koi and goldfish have been released into rivers in South Africa since the 1800&rsquo / s for food and sport fish and have since spread extensively. These fish are present in most of the river systems in South Africa and pose an additional threat the indigenous cyprinids in the Western Cape. Monogenean parasites of the genus Gyrodactylus are of particular concern, as their unique biology renders them a possible threat. Gyrodactylus kherulensis and G. kobayashii were identified from koi and goldfish respectively imported from Asia, Europe and locally bred fish. Morphometrics and the use of statistical classifiers, which includes univariate (ANOVA and Kruskal-Wallis), bivariate (Pearson&rsquo / s correlation) and multivariate (Principal Component Analysis) placed the two species within their respective groups. There was some intraspecific variation among the different populations collected from the various locations, especially in the hamulus and ventral bar features, but the marginal hooklets, however, remained static for both helminth species.</p>
3

Risk analysis and potential implications of exotic Gyrodactylus species on cultured and wild cyprinids in the Western Cape, South Africa

Maseng, Monique Rochelle January 2010 (has links)
<p>Koi and goldfish have been released into rivers in South Africa since the 1800&rsquo / s for food and sport fish and have since spread extensively. These fish are present in most of the river systems in South Africa and pose an additional threat the indigenous cyprinids in the Western Cape. Monogenean parasites of the genus Gyrodactylus are of particular concern, as their unique biology renders them a possible threat. Gyrodactylus kherulensis and G. kobayashii were identified from koi and goldfish respectively imported from Asia, Europe and locally bred fish. Morphometrics and the use of statistical classifiers, which includes univariate (ANOVA and Kruskal-Wallis), bivariate (Pearson&rsquo / s correlation) and multivariate (Principal Component Analysis) placed the two species within their respective groups. There was some intraspecific variation among the different populations collected from the various locations, especially in the hamulus and ventral bar features, but the marginal hooklets, however, remained static for both helminth species.</p>
4

Risk analysis and potential implications of exotic Gyrodactylus species on cultured and wild cyprinids in the Western Cape, South Africa

Maseng, Monique Rochelle January 2010 (has links)
Magister Scientiae (Biodiversity and Conservation Biology) / The expansion of the South African aquaculture industry coupled with the lack of effective parasite management strategies may potentially have negative effects on both the freshwater biodiversity and economics of the aquaculture sector. Koi and goldfish are notorious for the propagation of parasites worldwide, some of which have already infected indigenous fish in South Africa. Koi and goldfish have been released into rivers in South Africa since the 1800’s for food and sport fish and have since spread extensively. These fish are present in most of the river systems in South Africa and pose an additional threat the indigenous cyprinids in the Western Cape. Monogenean parasites of the genus Gyrodactylus are of particular concern, as their unique biology renders them a possible threat. Gyrodactylus kherulensis and G. kobayashii were identified from koi and goldfish respectively imported from Asia, Europe and locally bred fish. Morphometrics and the use of statistical classifiers, which includes univariate (ANOVA and Kruskal-Wallis), bivariate (Pearson’s correlation) and multivariate (Principal Component Analysis) placed the two species within their respective groups. There was some intraspecific variation among the different populations collected from the various locations, especially in the hamulus and ventral bar features, but the marginal hooklets, however, remained static for both helminth species. This illustrates again the importance of the minor variations in the marginal hook features in gyrodactylid taxonomy. Infection trials conducted by co-habitation of infected koi and goldfish with two indigenous redfin minnow species, Pseudobarbus burchelli and P. phlegethon showed that both G. kherulensis and G. kobayashii could successfully transfer and establish themselves on P. phlegethon, where the infection increased rapidly initially, but remained relatively constant thereafter. P. burchelli appeared to be inherently resistant as the parasite population growth rate initially remained steady, until the infection died off. The wild-caught indigenous fish were however not infected with any exotic Gyrodactylus species, but a new species, G. burchelli n. sp. described from the body surfaces of P. burchelli. / South Africa

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