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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.
11

Life history, population dynamics and conservation status of Oldenburgia grandis (Asteraceae), an endemic of the Eastern Cape of South Africa

Swart, Carin January 2008 (has links)
Oldenburgia grandis is a rare, long-lived woody paleoendemic of the Fynbos Biome of South Africa. Confined to quartzite outcrops, it has a small geographic range and narrow habitat specificity. O. grandis responds to its fire-prone environment by resprouting. Elasticity analysis of O. grandis reveals that growth and fecundity were traded off for persistence of adult, mature and sapling stages. Morphological adaptations such as a corky fire-resistant bark and the ability to resprout after fire are traits that O. grandis have evolved to persist in a frequently disturbed environment. Population growth rate for sites undisturbed by fire for a number of years (l = 1.01) and sites at various stages of recovery after fire (l = 1.00) were very similar. The highest variation in transition probabilities for all sites was seen in the persistence of the seedling stage and growth from seedling to sapling. Observed population structure and stable stage distribution determined by the matrix model show that sites recently undisturbed by fire had high abundances of the adult and sapling stages. A peak in sapling stages was seen for the stable stage distribution where similar peak in sapling numbers were seen for population structures of sites at various stages of recoveryafter fire. Favourable environmental conditions for the persistence of O. grandis populations include no fire with transition probabilities between the observed minimum and maximum and fire frequency at a 10 year interval where seedling protection from the fire is high and adult and mature mortalities during the fire are low. Stochastic environmental events that could put populations (particularly small populations) at an increased risk of extinction include high to moderate fire intensities where seedling protection from the fire is low and adult and mature mortalities are high as a result of the fire.
12

Anthropogenic threats to resident and dispersing African wild dogs west and south of the Kruger National Park, South Africa / Antropogenic threats to resident and dispersing African wild dogs west and south of the Kruger National Park, South Africa

Watermeyer, Jessica Patricia January 2012 (has links)
African wild dog Lycaon pictus populations are declining and the species is listed as Endangered by the IUCN. The Kruger National Park (KNP) is home to the only viable population of wild dogs in South Africa, but census results reveal consistently low numbers since the late 1990s. Wild dogs display wide-ranging behaviour and it is possible that the species might frequently use unprotected lands adjacent to the KNP. However, very little is known about wild dog movements beyond the boundaries of the KNP, and whether or not adjacent land owners are tolerant of the species. Significantly, threats along the boundaries may have negative consequences for the KNP population. This research investigated the dispersal habits of wild dogs beyond the western and southern boundaries of the KNP, and gathered information on human tolerance, and anthropogenic threats in an area of mixed land use. The land west of the KNP presented the best prospect for wild dog range expansion. The wild dog packs operating outside the KNP had smaller home ranges and less home range overlap than the packs operating within the KNP. In addition, my data suggested that the development of conservancies and the formation of ecotourism-based land use practices would be beneficial for wild dog conservation. Failed wild dog dispersals due to snaring and human persecution could threaten the genetic stability and persistence of the KNP population. Therefore, raising awareness and an understanding of the plight of wild dogs is important for improving land owner perception and tolerance outside of protected areas. The rapidly increasing human population continues to infringe on protected lands and fragment landscapes, thus cooperation from individual land owners is vital for the conservation of free-ranging large carnivores.
13

The illegal reptile trade - a criminological perspective

Herbig, Friedo Johann Willem 30 June 2003 (has links)
The illegal reptile trade quandary in the Western Cape province is strategically and chronologically addressed in this thesis with the implicit intention of revealing its gamut and underlying dynamics, developing a pragmatic, parsimonious and authentic conservation crime category with clearly delineated parameters, and formulating an integrated theoretical explanation regarding its aetiology that will adequately explicate herpetological, and hopefully also other forms of natural resource, crime and deviance. The thesis, by essentially transcending traditional, stereotypical edicts, throws new light on a severely neglected and underestimated form of natural resource exploitation, highlighting the need for reptiles, as the sentinels of the state of our environmental health to be preserved and perpetuated for, in the final analysis, the benefit of human kind. Through an essentially explorative enquiry, utilising an integrated qualitative -quantitative research approach, the concept of conservation crime, as a vanguard to an innovative and unified conservation criminology, is introduced in this thesis in the form of unambiguous adjunct of the mainstream criminological discipline. It is, furthermore, utilised as a conduit within the herpetological crime framework to enrich the criminological discipline as a whole, broaden its frontiers, promote effective and focussed intervention/mitigation initiatives, as well as stimulate interest for further investigation in this field. Fragmented, antiquated and nebulous legislation, deficient conservation and related role-player organisational capacity and inconsistent penalties, in concert with apathetic (and decidedly generic) societal attitudes and traditional pessimistic rubric regarding reptiles, emerge as fundamental proclivities impeding the effective intercession and management of the natural resources embodied in this sphere. Injudicious manipulation of the Western Cape's scarce and specialised reptile resources and the biodiversity ramifications such exploitation realises portend the intensification and diversification potential of such criminality. Conservation criminology, as developed and presented in this thesis, underscores the significant contribution this field of criminology can make in comprehending the illegal manipulation/exploitation of herpetological and other natural resources, expanding and enhancing its theoretical constructs and implementing justice through decisive, dedicated and holistic intervention programmes/strategies in order to defend the inherent right to the continued existence of all reptile species. / Crimonology / D. Litt et Phil. (Criminology)
14

The illegal reptile trade - a criminological perspective

Herbig, Friedo Johann Willem 30 June 2003 (has links)
The illegal reptile trade quandary in the Western Cape province is strategically and chronologically addressed in this thesis with the implicit intention of revealing its gamut and underlying dynamics, developing a pragmatic, parsimonious and authentic conservation crime category with clearly delineated parameters, and formulating an integrated theoretical explanation regarding its aetiology that will adequately explicate herpetological, and hopefully also other forms of natural resource, crime and deviance. The thesis, by essentially transcending traditional, stereotypical edicts, throws new light on a severely neglected and underestimated form of natural resource exploitation, highlighting the need for reptiles, as the sentinels of the state of our environmental health to be preserved and perpetuated for, in the final analysis, the benefit of human kind. Through an essentially explorative enquiry, utilising an integrated qualitative -quantitative research approach, the concept of conservation crime, as a vanguard to an innovative and unified conservation criminology, is introduced in this thesis in the form of unambiguous adjunct of the mainstream criminological discipline. It is, furthermore, utilised as a conduit within the herpetological crime framework to enrich the criminological discipline as a whole, broaden its frontiers, promote effective and focussed intervention/mitigation initiatives, as well as stimulate interest for further investigation in this field. Fragmented, antiquated and nebulous legislation, deficient conservation and related role-player organisational capacity and inconsistent penalties, in concert with apathetic (and decidedly generic) societal attitudes and traditional pessimistic rubric regarding reptiles, emerge as fundamental proclivities impeding the effective intercession and management of the natural resources embodied in this sphere. Injudicious manipulation of the Western Cape's scarce and specialised reptile resources and the biodiversity ramifications such exploitation realises portend the intensification and diversification potential of such criminality. Conservation criminology, as developed and presented in this thesis, underscores the significant contribution this field of criminology can make in comprehending the illegal manipulation/exploitation of herpetological and other natural resources, expanding and enhancing its theoretical constructs and implementing justice through decisive, dedicated and holistic intervention programmes/strategies in order to defend the inherent right to the continued existence of all reptile species. / Crimonology / D. Litt et Phil. (Criminology)

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