M.Sc. (Zoology) / Blood samples were obtained from 42 Cape (Gyps coprotheres) Vultures during the period 1990 to 1991. Nestlings were sampled at two natural localities namely the Scheerpoort and Manoutsa colonies. Samples from captive birds ranging in age from immature to mature were obtained from four locations which include the Johannesburg Zoo, Tygerberg Zoo, De Wildt Cheetah Research and Breeding Station and World of Birds. The main objective of the study was to describe the population genetic structure of G. coprotheres by means of a protein electrophoretic examination. The optimum electrophoretic conditions were determined for maximum resolution of the protein systems examined. Allele frequency data assessed at 34 structural gene loci were obtained. As measures of variability, the perc~ntage polymorphic loci and average heterozygosity were calculated for the Cape vulture and values obtained were 11.76\ and 0.021 respectively. Both of the latter values are less than half the values reported for the majority of other avian species. The electrophoretic data were utilised in two population genetic simulation programmes and it was determined that the variation present in the populations of G. coprotheres studied may disappear within the next 35 generations. The blood samples were also subjected to a toxicological examination. Concentrations of DDT and its derivatives were measured by gaschromatographic analyses. Biocide levels were detected in ppb and adjusted to ppm by a conversion factor of 150. Quantifiable levels of DDT, DOD and DOE were detected in 72.4\, 60.0% and 89.7% of the individuals respectively. DOE is one of the major metabolites of DDT and the discussion was focused on levels thereof.

Scavenging bird of prey have been abundant throughout the Mediterranean region for years, establishing a food acquisition relationship with human activities, their characteristics make them especially suitable for the recognition of dangerous environmental conditions. The West Nile Virus (WNV) considered the most widespread arbovirus has been previously discovered in our 3 species of studio. The analyses from feather follicles and serum samples obtain from different regions in Spain shown a higher seroprevalence against West Nile virus or cross-reacting flaviviruses in the northern part of the country and in the Canary archipelago. Our results showed a general seroprevalence of 19.8% (34 out of 172), a prevalence of 19,8% in Egyptian vultures, a prevalence of 27.1% (13 out of 48) in Griffon vultures and no prevalence in Cinereous vultures. Differences were observed for the body condition off Griffon and Egyptian vultures when anthropized and not anthropized areas were compared, being significantly worse in anthropized areas for Griffon vultures and significantly better for Egyptian vultures. The exposure to the virus of the nestlings increased with the age, showing a higher tend in Egyptian vultures than in Griffon vultures. Our results confirm the circulation and a higher seroprevalence of West Nile virus or cross-reacting flaviviruses than in previous studies.

No description available.

M.Tech. (Architectural Technology) / Please refer to full text to view abstract

Dans le contexte actuel des changements globaux, les êtres vivants sont soumis à de nouvelles pressions sélectives dans des environnements modifiés par les activités anthropiques, et nous assistons à l’émergence de pièges évolutifs. Se déplacer peut être appréhendé comme une conséquence de ces changements, mais aussi comme l’opportunité pour un individu, une population ou une espèce, de s’adapter, à diverses échelles spatio-temporelles, en changeant de site d’alimentation, de domaine vital ou d’aire de répartition. Dans mon travail de thèse, je me suis intéressée aux comportements de prospection alimentaire du vautour fauve (Gyps fulvus), appartenant à la guilde fonctionnelle des nécrophages stricts, qui est la plus menacée parmi les oiseaux à l’échelle mondiale. Des plans de conservation ont été mis en place pour enrayer leur déclin, dont certaines mesures de gestion comme le soutien alimentaire (SA) peuvent néanmoins constituer de véritables pièges évolutifs (des sites attractifs sous-optimaux) pour les vautours. A partir de l’analyse des déplacements journaliers à fine échelle d’individus équipés de balises GPS, et par l’étude des domaines vitaux, j’ai mis en évidence des différences intra- et inter-populationnelles en termes de stratégies d’occupation de l’espace et de recherche alimentaire chez les vautours fauves présents dans deux régions françaises où le SA est élevé (Causses) ou faible (Pyrénées). Grâce à de nouvelles méthodes pour quantifier les routines comportementales, j’ai démontré que les visites des vautours aux sites de SA sont peu stéréotypées et routinières dans les Causses, tant au niveau spatial que temporel. Malgré une utilisation de l’espace à large échelle très différente entre les Causses et les Pyrénées, ainsi qu’un budget temps différent (plus longue durée de vol dans les Causses), le budget énergétique diffère peu entre les deux populations. Au-delà du niveau de prévisibilité des ressources – inhérent au SA - j’ai identifié d’autres facteurs influençant vraisemblablement les prises de décision comportementales des individus : l’état motivationnel de l’individu lié à son statut de reproduction, et les conditions aérologiques locales. Inscrit à l’interface entre écologie comportementale et biologie de la conservation, mon travail de doctorat participe à une meilleure compréhension des patrons d’utilisation de l’espace et des processus en jeu à différentes échelles spatio-temporelles chez une espèce nécrophage stricte. Les acteurs de la conservation pourront s’appuyer sur mes résultats et propositions de gestion pour maintenir les comportements naturels des vautours, et à termes, la viabilité des populations. / In the current context of global change, organism are exposed to new selective pressures in their environments modified by human activities, and we observe the emergence of evolutionary traps. Moving can be interpreted as a consequence of these global changes, but also as the opportunity for an individual, a population or a species to adapt, at different spatio-temporal scales, by modifying their feeding sites, home range or distribution area. During my PhD, I was interested in studying the foraging of Griffon vultures (Gyps fulvus) belonging to the functional guild of obligate scavengers, which are the most threatened birds worldwide. Conservation plans have been carried out to limit their decline, proposing management practices such as supplementary feeding (SF) that may constitute an ecological trap (attractive but suboptimal sites) for vultures. Analysing of fine-scale daily movements and home ranges of individuals equipped with GPS devices, I found significant differences of foraging strategies and space use patterns in vultures from two French regions with low vs high SF (Pyrenees vs Causses). Using recent methods to quantify behavioral routines, I demonstrated that vultures visited SF stations in the Causses with low level of routine, both spatially and temporally. In spite of the distinct large-scale movement patterns between the individuals in the Causses and the Pyrenees, as well as different time-budgets (birds spending more time in flight in the Causses), energy expenditure estimated at the population level are quite similar. Beyond the level of resource predictability - inherent to SF - I highlighted other factors likely to influence individuals’ behavioral decision-making: the individual’s motivational state related to its breeding status, and local aerological conditions. At the interface between behavioral ecology and conservation biology, my work should contribute to a better understanding of the space use patterns in an obligate scavenger and the processes involved at different spatio-temporal scales. Conservationist will be able to use my results and management recommendations to maintain the natural behavior of vultures and, finally, populations’ viability.

Over the last decade, three species of Gyps vultures on the Asian subcontinent have declined dramatically in population numbers, some as much as 97 to 99%. Although the initial cause was believed to be infectious, it was later shown to be due to an inadvertent exposure to diclofenac via the food chain. In order to protect the remaining wild vultures, diclofenac needed to be removed from the food chain. Unfortunately the Indian government was reluctant to ban diclofenac until an alternate veterinary non-steroidal anti-inflammatory drug (NSAID) that was both safe in vultures and effective in cattle could be identified. Although meloxicam was tentatively identified as this drug, toxicity testing still needed to be undertaken. Using a previously validated model, two studies were undertaken to determine the acute toxic effect of diclofenac in vulture as well as to ascertain if the drug had the potential to accumulate. In the first study, meloxicam in formulation was shown to be safe as a single oral dose up to 2mg/kg in African White Backed-Vultures (Gyps africanus). To further demonstrate the safety of food borne meloxicam, vultures were exposed to meat rich in meloxicam residues, with once again no signs of toxicity being evident. In the second study the drugs ability to accumulate was evaluated pharmacokinetically in Cape Griffon Vultures (Gyps corprotheres). From this study meloxicam was shown to have a very short half-life of elimination, making it unlikely that the drug could be a cumulative toxin. This was subsequently confirmed clinically by the absence of toxicity in birds receiving repeated doses of meloxicam. Although meloxicam was shown to be adequately safe, the safety of other veterinary NSAIDs still required elucidation. While further testing in vultures would have been possible, the small population size of the various vulture species made this unethical. Therefore a surrogate species needed to be identified. With the domestic chicken (Gallus domesticus) being commonly available, attempts were made to validate the chicken as a model. Although the dosed chickens did show similar toxicity patterns from clinical pathology to histopathology, a major problem was their higher tolerance making it impossible to use them as a surrogate. It was, however, concluded that the domestic chicken may be used in mechanistic studies in an attempt to establish an in vitro model. From the mechanistic studies both diclofenac and meloxicam were directly toxic to chicken and vulture renal tubular epithelial cells following 48h of incubation. It was later shown that this toxicity was associated with an increased production of reactive oxygen species (ROS), which could be temporarily ameliorated by pre-incubation with uric acid due to its anti-oxidant activity. When cultures were incubated with either drug for only two hours, meloxicam showed no toxicity in contrast to the cellular toxicity present for diclofenac. In both cases no increase in ROS production was evident. In addition diclofenac influenced the excretion of uric acid by interfering with p-amino-hippuric acid channels. The effect on uric acid excretion persisted after the removal of the diclofenac. It was therefore concluded that vulture susceptibility to diclofenac results from a combination of an increase in cellular ROS, a depletion of intracellular uric acid concentration and most importantly the drug’s long half-life in the vulture. Unfortunately the importance of the drug’s half-life in the toxicodynamics makes it unlikely that in vitro testing will be possible. / Thesis (PhD (Paraclinical Sciences))--University of Pretoria, 2007. / Paraclinical Sciences / unrestricted

The aim of the study was to determine the consequences of elephant (Loxodonta africana) impact on selected nesting sites of avian fauna and other species in the Associated Private Nature Reserves. The study also aimed at answering key questions on how the architecture of trees influence nest site suitability and what landscape features affect nest site location. Furthermore the type of impact that elephants have on specific nesting sites was determined and how this would affect the short term persistence of these trees. The facillitatory role of elephants was examined by looking at the type of impact that produces gum exudants as well as what gum is selected for by primates and whether primary branch breaking may lead to the creation of nesting sites for species such as the southern ground hornbill (Bucorvus leadbeateri). / Environmental Sciences / M. Sc. (Environmental Management)

The broad aim of this study is to show, through a comparative and contrasting analysis of three thematically related texts - namely Peter Abrahams's Mine Boy; Alan Patan's Cry, the Beloved Country and Phyllis Altman's The Law of the Vultures - the ideologically mediated nature of the relationship between the 'real' history which constituted their context, and the representations of it in the historical realist form. An examination afthe texts' characters and events; political formulations, and formal devices reveals three very different representations of the same object. This diversity is significant in so far as it supports a Marxist conceptualisation of the [historical] realist text as a production of ideology as opposed to a portrayal of reality. The study considers the nature of the relationship between each text and ideology in terms of three aspects of this relationship: the 'objectively determinable' relation between history, ideology and text; the ideology of the text itself, and the mode of a text's insertion into an 'ideological sub-ensemble.' In relation to the modes of a text's insertion into an ideological sub-ensemble, my specific aim is to assess the extent to which each text actually challenges the political dispensation to which it was addressed. / Thesis (M.A.)-University of Natal, Durban, 2000.

The aim of the study was to determine the consequences of elephant (Loxodonta africana) impact on selected nesting sites of avian fauna and other species in the Associated Private Nature Reserves. The study also aimed at answering key questions on how the architecture of trees influence nest site suitability and what landscape features affect nest site location. Furthermore the type of impact that elephants have on specific nesting sites was determined and how this would affect the short term persistence of these trees. The facillitatory role of elephants was examined by looking at the type of impact that produces gum exudants as well as what gum is selected for by primates and whether primary branch breaking may lead to the creation of nesting sites for species such as the southern ground hornbill (Bucorvus leadbeateri). / Environmental Sciences / M. Sc. (Environmental Management)

The Cape Vulture (Gyps coprotheres), a southern African endemic, is a species currently listed on the IUCN Red List as “Threatened” due to its 66-81% decline over the past 50 years. South Africa and Lesotho hold 90% of the global population, which are focused at two core areas, namely northern central South Africa and eastern South Africa. This species provides important ecological services yet faces numerous anthropogenic threats. An emerging threat in the south eastern part of South Africa is that of wind energy development. Understanding the movement and roosting behaviour of the Cape Vulture may mitigate potential collisions if areas of high use are avoided. Juvenile Cape Vultures, who naturally suffer high mortality rates, are known to forage extensively over a wider landscape and as a consequence may face a greater assortment of threats. The overall aim of this study therefore was to determine the ranging and roosting behaviour of juvenile Cape Vultures in the Eastern Cape Province, South Africa. In order to achieve this aim, i) the ranging behaviour and habitat use were determined and ii) roost sites and factors that influence roost site selection were determined. Using five juvenile Cape Vultures tagged with Global Positioning System (GPS/GSM) transmitters, home range sizes, distance travelled from the nest and habitat use were determined. Home range was determined through kernel density estimates and distance travelled from the nest was determined through the Euclidean distance. Habitat use was determined by overlaying the home range size onto a merged layer of all protected areas and the National Land Cover Database of South Africa. To determine roost sites, data from the tagged vultures were split into encamped and exploratory movements using a mixture model in a cluster analysis setting. Encamped movements were associated with roost sites. Roost density was determined around the natal colony using predetermined buffer sizes and a generalised linear mixed model (GLMM) fitted to the data. Conditions considered favourable for roost sites were based on previous research conducted on cliff-nesting species and a GLMM conducted. Juveniles increased their home range progressively for the first two months, then exhibited a rapid increase in size associated with dispersal from the colony. Distance from the nest increased rapidly following the dispersal period. Protected areas and woody vegetation were areas of preferred habitat. The highest density of roosts for juveniles was located within 20 km’s from the breeding colony and decreased further away. Roost sites that were favoured for juveniles and adult birds were those that were located close to colonies, had low accessibility to terrestrial predators and were in areas of high wind speed. The orientation of the cliff into the prevailing wind direction was also a determining factor. Roosting sites and foraging areas are important spatial determinants of Cape Vulture behaviour and the identification of such areas can help with conservation management. With the additional threat of wind development in areas highly utilised, wind farms located too close to colonies could have a devastating impact on the Cape Vulture population. Therefore, this study highlights the importance of conservation buffer zones as no-go areas for wind energy development around vulture colonies.