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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.
31

A genetic perspective on leopard (Panthera pardus) conservation units across southern Africa

Thacker, Thomas M 17 March 2022 (has links)
Conservation units are a tool to guide policy such that conservation goals can be achieved. These units should ideally synthesise a wide array of data – genetic, ecological, demographic – to identify the appropriate scales at which conservation actions can then be directed. Despite being the most widespread of all felids in Africa, and facing numerous threats across its range, it has been proposed that the entirety of southern Africa be considered one conservation unit for leopards (Panthera pardus pardus). This proposal does not take into consideration the likelihood of existing population genetic structure across an increasingly fragmented landscape. Further complicating regional leopard conservation is the variability in conservation policies among the geopolitical leopard-range states. Within this single proposed conservation unit, the patchwork of different legislation does not support a unified policy for leopard conservation. Using a population genetic perspective, this study explores and tests the values and shortcomings of southern Africa as a single conservation unit, and explores the importance of leopard range states within the context of conservation units. Parallel investigations of leopard microsatellite genotype data within the framework of a genetic population study spanning eight countries across southern Africa were carried out. This study presents consilient evidence supporting the finding that southern Africa contains six clusters of unique genetic lineages, and as such does not constitute a single genetic unit. Furthermore, it is shown here that the spatial genetic structure that exists does not correlate with the separate geopolitical range states. Leopard range states within southern Africa instead capture varying levels of unique genetic structure and thus are not of equal value with respect to the conservation of genetic lineages. These findings have several implications for leopard conservation across the region. While the data presented here specifically consider a genetic element of conservation units, they do suggest shortcomings in adopting either the entirety of southern Africa as a single unit or separate geopolitical range states as conservation units. The variability in leopard conservation policy across southern Africa is unlikely to sufficiently protect their existing regional genetic structure. If conservation units are indeed a tool to guide conservation policy, then the southern Africa unit for leopards is potentially less effective than a smaller unit whose spatial scale more accurately captures the discrete variation in population genetic structure. Genetic diversity and population structure is an important component of conservation units and should not be neglected. Currently, however, an appropriate framework allowing for conservation policy to be informed at the necessary scale does not exist; although the establishment of Transfrontier Conservation Areas speaks to the growing acknowledgement that conservation needs to evolve beyond the historical confines of geopolitical range states. The evidence presented here further supports the need for a rethinking of existing policy structures.
32

Diet and foraging behaviour of Macaroni and Chinstrap penguins at Bouvetøya, South Atlantic Ocean

Huyser, Onno Adrian Wallace January 2000 (has links)
Bibliography: leaf 195.
33

Valuing an ecotourism resource : a case study of the Boulders Beach African penguin colony

Lewis, Sarah E F January 2011 (has links)
The colony of African Penguins at Boulders, Simon's Town on the southern Cape Peninsula, Western Cape formed in 1985, and is now a major ecotourism destination. The African Penguin is listed as Endangered due in part to competition with commercial fisheries. Improvements in the spatial management of these fisheries could assist with the conservation of the penguins, but would be costly. Various techniques were used to estimate the value of the colony, and to assess its impact on the economy of the southern Peninsula.
34

A camera trap assessment of factors influencing leopard (Panthera pardus) habitat use in the Nouabalé-Ndoki National Park, Republic of Congo

Mavinga, Franck Barrel 21 February 2019 (has links)
Leopards (Panthera pardus) are faced with increasing levels of anthropogenic pressure resulting in population declines across much of their historical range. While there is relatively limited knowledge of leopards occurring in African rain forests, their abundance and distribution is assumed to be impacted by a combination of several anthropogenic factors, most notably loss of prey and habitat conversion. In this study I used a long-term camera trap array that forms part of the Tropical Ecology, Assessment and Monitoring (TEAM) project - Terrestrial Vertebrate (Camera Trapping) Monitoring Protocol, to estimate the species richness of mammals, the relative abundance of leopard prey species and leopard habitat use in the Nouabalé-Ndoki National Park (NNNP) in the Republic of Congo. I investigated the impact of different environmental and anthropogenic factors on leopard occurrence at two camera trap arrays (a northern and southern cluster) within the NNNP using occupancy modelling. While there were no significant differences in mammalian species richness between the two clusters there was a higher relative abundance of the preferred prey species of leopards in the northern cluster. A total of 106 leopard photographic events were recorded across all camera traps and all survey years. The top occupancy model produced an average probability of site use (ψ) over all sites of 0.52 ± 0.14 (SE). The covariate specific β-coefficient estimate suggests that leopard occurrence and detectability were positively correlated with both the relative abundance of the blue duiker (Philantomba monticola) and the distance to the nearest river (β =0.062 ± SE 0.053 and 6.55 ± SE 10.84, respectively). Therefore there was no support for the prediction that the probability of leopard habitat use increases with a higher relative abundance of all potential prey species, nor was there support for the prediction that leopard habitat use would be higher further away from human settlements (β =3.42 ± SE 2.94). 2 Leopard habitat use was higher in the southern cluster which may be linked to the denser understory that would provide greater cover which is important for improved hunting success in leopards. Together, these results suggest that both the prey species and leopards appear to be thriving within the NNNP with limited evidence of anthropogenic impacts despite an increase in commercial logging and the itinerant bushmeat hunting in the peripheral area. It would be worth expanding the existing camera trap arrays to cover a greater spatial extent within NNNP and hence allow for a more detailed analysis of edge effects and to detect the potential impacts of anthropogenic activities which are predicted to increase in selected villages in the periphery of the park.
35

The status and conservation of common hippopotamuses in Virunga National Park

Kujirakwinja, Deo January 2010 (has links)
No description available.
36

Heat tolerance of Southern Pied Babblers in the Kalahari Desert : how will they respond to climate change?

Du Plessis, Katherine January 2011 (has links)
An increasing incidence of mass mortalities of birds in hot deserts suggests that birds may be appropriate candidates for assessing how natural selection, under the influence of climate change, drives adaptation. ... The effects of ambient temperature on daily weight gain, foraging effort and efficiency and the presence of heat-dissipation behaviours were assessed to determine the mechanisms by which increased temperature affect babbler body condition.
37

Assessment of pesticide concentrations in environmental and biological parameters from two Kenyan Rift Valley Lakes

Gudka, Masumi January 2012 (has links)
Includes abstract. / Includes bibliographical references. / In the last two decades Kenyan agriculture has developed rapidly. In particular, horticultural and floricultural activities have intensified on the riparian fringe of Lake Naivasha, a RAMSAR site. The lake supports a large variety of wildlife and avifauna in particular. In the 1980s, the African Fish-Eagle (Haliaeetus vocifer) population on the lake was the densest in Africa. As a top predator resident in the Kenyan Rift Valley Lakes the African Fish-Eagle is a good indicator of general ecosystem health but is also highly susceptible to toxic effects of pesticide contamination...Globally, most organochlorine pesticides have been banned, but endosulfan, HCH and methoxychlor are widely used in Kenya, while aldrin, dieldrin and lindane are restricted and DDT, endrin, and heptachlor banned. Studies examining residue levels of these harmful chemicals in African Fish-Eagles are limited to small sample sizes examined in the 1970s and 1980s. This study is the first comprehensive investigation of organochlorine residue contamination in biological and environmental parameters from Lake Naivasha and the control water body at Lake Baringo.
38

Host plant associations of two cochineal insect species, Dactylopius ceylonicus and D. opuntiae (Dactylopiidae: Hemiptera), on the invasive cactus species Opuntia monacantha, O. ficus-indica and a possible hybrid cactus, in South Africa

De Souza, Nadia R January 2014 (has links)
Includes bibliographical references. / Several cochineal species have been used with great success for biological control of invasive cactus species, both in South Africa and elsewhere. Although most cochineal species are oligophagous, they are all exclusively associated with opuntioid cacti and therefore pose minimal risk of non-target effects in the Old World where there are no native Cactaceae. However, the ability of cochineal to use more than one host plant species has validated reports of inadvertent displacement of Dactylopius ceylonicus (the original agent released in 1913) by D. opuntiae (which was originally released on Opuntia ficus-indica in 1938) on O. monacantha in South Africa. There are also reports that the two cactus hosts, O. monacantha and O. ficus-indica, have hybridized in South Africa, but there are uncertainties as to which of the two cochineal species is associated with the alleged hybrid. The primary aim of this study was to determine the present status of D. ceylonicus and D. opuntiae on O. monacantha and on the possible hybrid. Cochineal samples were collected off cactus plants from sites in the Eastern Cape and Western Cape and identified using bioassays and morphological features. The performance of each cochineal species on each of the three cactus hosts (O. monacantha, O. ficus-indica and the hybrid) was determined through measures of female developmental rates, survival and mass at reproductive maturity. Results showed that D. ceylonicus remains present on O. monacantha at each of seven study sites, while D. opuntiae did not occur on O. monacantha at any of the sites. However, D. opuntiae is capable of establishing on O. monacantha, O. ficus-indica and the possible hybrid cactus under laboratory conditions. Dactylopius ceylonicus is also compatible with both O. monacantha and the possible hybrid, although it did not establish on O. ficus-indica. These findings showed that D. ceylonicus has not been displaced by D. opuntiae on O. monacantha in South Africa and it is expected that O. monacantha will continue to be kept under excellent biological control into the future. Results also indicated that possible hybridisation between the two Opuntia species has not produced a new taxon that is immune to either of the two control agents. However, further research is required to improve our understanding of this new plant taxon and confirm it will be suppressed by one or both of the cochineal species.
39

An experimental assessment of the efficacy of falconry to mitigate human-wildlife conflict: Egyptian Geese Alopochen aegyptiaca at golf courses

Atkins, Alexander January 2015 (has links)
Includes bibliographical references / Human-wildlife conflicts are increasing globally and are believed to be one of the most prevalent and intractable issues that face conservation biologists today. One such conflict is found on golf courses, where high numbers of geese can come into conflict with residents and members. In South Africa, the indigenous Egyptian Goose Alopochen aegyptiaca population has increased dramatically over recent years and as a result they are often seen as nuisance animals whose population requires active management. Most non-lethal methods of goose control have had little success due to habituation to their presence, whilst the use of lethal methods are often deemed socially unacceptable. In this study we experimentally investigated the efficacy of falconry as a management tool to mitigate human-wildlife conflict. We hypothesised that the use of falconry would re-establish a landscape of fear, whereby habitat choice is influenced by the perceived fear of predation, resulting in the local departure of geese to a safer habitat, thereby reducing the population of geese to a tolerable level. Absolute counts of geese and analysis of vigilance levels were conducted at three golf courses in the Western Cape which included two control sites and a treatment site. The results of the experiment indicate that goose abundance declined by 73% at the treatment site after falconry was initiated, and that this was well over the losses due to direct predation. Vigilance levels increased by 7 6% during the treatment period, with no such changes observed at either control site. Additionally, vigilance was higher when filmed from a golf buggy compared to when filmed on foot, which may suggest the geese also learned to associate the golf buggy with the threat of predation, enhancing the overall efficacy of the falconry. While there is a relatively small lethal aspect to falconry, the results of this study confirm that a reduction in the population of geese can be achieved by simulating the naturally occurring non-lethal effects of predation that have been lost in some habitats, as a result of anthropogenic changes to the landscape. To our knowledge, this is the first truly experimental test of the efficacy of falconry to reduce nuisance birds and these important ecological findings have relevance for techniques that people deploy for dealing with human wildlife conflict, particularly where lethal options are unfavourable.
40

Biodiversity survey towards conservation of subtidal reef habitats in KwaZulu Natal : biogeography and depth patterns

Lawrence, Cloverley January 2005 (has links)
Includes bibliographical references (pages 49-58). / Subtidal reef communities in KwaZulu-Natal (KZN), South Africa are poorly known. This lack of knowledge is problematic as the biodiversity of these reefs may be severely impacted and inadequately conserved. This study documents and describes subtidal benthic communities occurring on reefs at four depth categories along the whole length of the coast. A distinct difference between northern reefs from those in the south and central parts of the province emerged with substantiating evidence of a discrete biogeographic separation at Cape St Lucia. Pairwise ANOSIM tests found no significant differences in community composition of reefs along a depth range of 10 m to 30 m at nine localities in KZN. However, differences among localities were significant at both regional (R = 0.607, P = 0.1%) and local (R = (1.792, P = 0.1%) scales. In the north, trends in species assemblages and functional groupings revealed a higher percentage cover of fauna (mainly corals) at shallower depths and a greater coverage of algae on deeper reefs. In the southern localities algae dominated shallower reefs while filter-feeding epifauna were more prevalent at deeper depths. Species richness, evenness and diversity were highest at 10m in the northern coral-dominated region while in the central/south region diversity peaked in the intermediate depth zone (15 - 25 m). Appropriate measures to conserve representative habitats in each biogeographic zone are necessary. Further research to assess biodiversity at a finer scale, as well as the establishment oflong-term monitoring to quantify natural variability and human effects, are required.

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