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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 53 for “"alien species"”.
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Marine alien species of South Africa : threats and opportunities
… Africa, and the status of intertidal marine aliens was last assessed in 1990. I thus investigated the present distribution and status of three intertidal alien species (Mytilus galloprovineialis, Care in us maenas and Careinus aestuarii) and documented the presence and status of a previously …
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Modelling and empirical approaches for predicting the invasiveness of alien species.
… of global change that result from the release of alien species into novel environments. Where an introduced alien establishes a sustainable population, disperses and impacts native species then it is considered as invasive. Predicting the outcomes of alien introductions is critical for …
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Transfer of an Amphibian Renal Tumor Into Alien Species, Kindred Races and Hybrids
Made available in DSpace on 2014-12-04T22:45:46Z (GMT). No. of bitstreams: 1 0006019.pdf: 5948410 bytes, checksum: 13a27e2bbeeba37629646f28f184b047 (MD5) Previous issue date: 1953
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Fouled yachts : a vector for marine invasive alien species to South African shores?
… is an important vector for marine invasive alien species (MIAS) in many countries. There are various characteristics of a vessel that make it more susceptible to hull fouling. Yachts in three Western Cape marinas were surveyed to assess extent of fouling, hull maintenance patterns, travel …
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Marine alien species in Western Cape harbours, South Africa: A tool for stategically focusing monitoring efforts
Alien species are the second most important cause for the loss in biodiversity globally, after habitat destruction. Marine alien species are transferred across the globe through various vectors, including ballast water, hull fouling, aquaculture facilities and the aquarium and pet trade. Ballast …
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Biological control of alien species (Prosopis) in South Africa : the role of introduced seed-feeding bruchids
… for biologicval control of mesquite, Prosopsis species, in South Africa is deemed to have failed because the beetles are supposed to be unable to compete with livestock which utilise the seed pods of mesquite extensively as forage. These assumptions have been made without any evidence as to how …
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Testing the use of port biological baseline surveys to support relevant marine alien species management applications in Africa
The prevention of non-native marine species introductions is the first line of defense in the management of alien invasive species problems occurring on coastlines around the world. Ports and the shipping industry have been targeted as a sector requiring increased attention and regulation to reduce …
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History and status of oyster exploitation and culture in South Africa, and the role of oysters as vectors for marine alien species
… with S. margaritacea being the most targeted species. The commercial harvesting areas are along the Southern Cape coast and in KwaZulu-Natal. The Southern Cape coast is the largest harvesting area with 102 of the 145 pickers employed in the region. Commercial and recreational harvesting is …
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Alien plant invasion on the Agulhas Plain : a detailed description of invasion patterns
Invasive alien species occur within several biodiverse regions of South Africa. It is not yet fully understood the extent to which invasive alien species affect natural vegetation. It is important to classify such species based on abundance and distribution in order to determine invasion patterns …
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Assessing the variations in alien plant communities within powerline corridors: A case study of Fundudzi and Khakhu Powerline Corridors
… patterns, and may also encourage the spread of alien plants. The spread of alien plants from one area to another through intentional and unintentional human activities is a serious threat to the world’s biodiversity, including that of South Africa. Vegetation management in powerline corridors in …
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The impact of pine plantations and alien invertebrates on native forest and fynbos invertebrate communities in Table Mountain National Park
… invertebrate diversity and endemism, extensive alien plant invasions and exotic pine plantations threaten and reduce native species richness. This study frames invasion ecology theory in a conservation context, and examines the impact of planting and felling pine on litter invertebrate …
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Assessing environmental factors structuring populations and movement dynamics of the invasive snail Tarebia granifera in a subtropical Austral reservoir
Invasive alien species continue to spread and proliferate in waterways worldwide, but environmental drivers of invasion dynamics lack assessment. Understanding alien species ability to self-disperse via locomotion following arrival to new environments is also critical for prediction of invasion …
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An Investigation into the role of Allelopathy in influencing plant diversity around Lantana Camara groves
Invasive alien species have become a serious threat to plant biodiversity in many parts of the world. Globally the threat to biodiversity due to invasive alien species is considered second only to that of habitat loss. Invasive species are thus a serious impediment to conservation and sustainable …
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Modelling the current and potential distribution of woody plants, with special emphasis on the importance of spatial scale and environmental factors
The relationship between species distribution and environment has always been a central issue in ecology. The primary aim of this thesis is to explore the role of abiotic and biotic factors in mediating the distribution of woody plants, particularly invasive alien species. Predictions of the future …
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Low cost, small-scale charcoal production in the Western Cape
… at least 80 was successfully produced from the alien species Acacia Saligna. Carbonisation was effected using a Tongan drum kiln and average yields on a dry basis of 19.1 (excluding fines production) were attained. With fines included, the yield increased to 31.4 . It was shown that the earnings …
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A study of aspects of the biology and distribution of freshwater crayfish in the Thames catchment
… an introduced (Pace as acus leniusculus. Dana.) species have been undertaken and attempts to evaluate some of the factors controlling distribution have been made. The specific influences of river engineering works on populations of A. pallipes have been studied in more detail. Data concerning A. …
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Rapid and portable molecular detection tools for reptile pest priority species in Australian environmental biosecurity scenarios
… resulted in the introduction of many invasive alien species into novel environments. Reptiles are considered particularly high risk, with many global examples of their detrimental impacts on both local environments and economies. The trade in exotic pets facilitates the transport of non-native …
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Remote sensing evaluation of Cape parrot habitat in the Eastern Cape: implications for conservation
… forest or the clearing of plantations and woody alien invasives. The overall accuracy of the classification was very high at 82%. Cross validated accuracies were all high ranging from 95 – 100%, with water having the highest accuracy and indigenous forest, eucalyptus spp., pine spp., and …
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The ecology and control of typha capensis in the wetlands of the Cape flats, South Africa
… growth, production and decomposition of the species in a Cape Flats wetland. The process of invasion by indigenous species rather than by alien species is discussed and the view that wetlands are threatened by mismanagement rather than by encroachment per se is examined. Finally, control …
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