Habitat partitioning, and an assessment of habitat suitability using presence data, of a large herbivore communitiy on a Zimbabwean private wildlife reserve

[摘要] ENGLISH ABSTRACT: The factors determining habitat selection of large herbivores, on a privatewildlife reserve in semi-arid southeastern Zimbabwe, were investigated.Gross vegetative structure, herbaceous composition and topographicfeatures thought to determine herbivore distribution were measured.Seasonal variation in resource distribution was considered, and researchtherefore extended over an entire year. Herbivore distribution andecological niche separation was explained through several importantenvironmental variables, and potential for inter-specific competitioninferred. Additionally, predictive habitat suitability models were designedfor each of the grazing species in the critical dry season.Herbivores showed a large degree of niche overlap in both the hotwetseason and the cool-dry season, when food resources were moreplentiful. Niche separation between grazers was pronounced in the hot-dryseason. Herbivore distribution was associated most closely with distanceto water, grass sward height, time since burn, woody plant density and bythe presence of predominant grasses, these being Urochloamossambicensis, Panicum maximum, Heteropogon contortus and Digitariaeriantha. Ecological separation of herbivores by the grasses P. maximum,H. contortus and D. eriantha was more indicative of associatedenvironmental variables than feeding niche separation.A GIS-based analysis, using species presence data and quantitativecoverages of environmental variables, produced maps of gradations ofhabitat suitability for grazing species during the dry season.Results of both analyses were integrated and gave a betterunderstanding of ecological separation, and possible competitiveinteractions, among the large herbivore community on Malilangwe Estate.Recommendations were made based on the interpretation of findings,within the context of available management options.

[发布机构] Stellenbosch University