Browsing by Author "Traill, Lochran (Lochran William)"

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    Habitat partitioning, and an assessment of habitat suitability using presence data, of a large herbivore communitiy on a Zimbabwean private wildlife reserve
    (Stellenbosch : University of Stellenbosch, 2003-12) Traill, Lochran (Lochran William); Bigalke, R. C.; University of Stellenbosch. Faculty of Agrisciences. Dept. of Forest and Wood Science.
    ENGLISH ABSTRACT: The factors determining habitat selection of large herbivores, on a private wildlife reserve in semi-arid southeastern Zimbabwe, were investigated. Gross vegetative structure, herbaceous composition and topographic features thought to determine herbivore distribution were measured. Seasonal variation in resource distribution was considered, and research therefore extended over an entire year. Herbivore distribution and ecological niche separation was explained through several important environmental variables, and potential for inter-specific competition inferred. Additionally, predictive habitat suitability models were designed for each of the grazing species in the critical dry season. Herbivores showed a large degree of niche overlap in both the hotwet season and the cool-dry season, when food resources were more plentiful. Niche separation between grazers was pronounced in the hot-dry season. Herbivore distribution was associated most closely with distance to water, grass sward height, time since burn, woody plant density and by the presence of predominant grasses, these being Urochloa mossambicensis, Panicum maximum, Heteropogon contortus and Digitaria eriantha. Ecological separation of herbivores by the grasses P. maximum, H. contortus and D. eriantha was more indicative of associated environmental variables than feeding niche separation. A GIS-based analysis, using species presence data and quantitative coverages of environmental variables, produced maps of gradations of habitat suitability for grazing species during the dry season. Results of both analyses were integrated and gave a better understanding of ecological separation, and possible competitive interactions, among the large herbivore community on Malilangwe Estate. Recommendations were made based on the interpretation of findings, within the context of available management options.