Habitat partitioning, and an assessment of habitat suitability using presence data, of a large herbivore communitiy on a Zimbabwean private wildlife reserve
Date
2003-12
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
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.
AFRIKAANSE OPSOMMING: Die bepalende faktore van habitat seleksie by groot herbivore op ‘n privaat wildreservaat in semi-dorre suidoos Zimbabwe is ondersoek. Globale plantegroei stuktuur, kruidagtige samestelling en topografiese eienskappe wat glo herbivoor verspreiding bepaal, is gemeet. Seisoenale variasie in hulpbronverspreiding is in ag geneem en dus het navorsing oor ‘n hele jaar gestrek. Herbivoor verspreiding en ekologiese nisskeiding is verduidelik deur verskeie belangrike omgewingsveranderlikes en die potensiaal vir interspesifieke kompetisie is afgelei. Boonop is voorspellende habitat-geskiktheidsmodelle ontwerp vir elk van die weidingspesies in die krities droë seisoen. Herbivore toon ‘n hoë graad van nis oorvleueling in sowel die warm, nat seisoen as die koel, droë seisoen wanneer voedingsbronne meer volop is. Nis verdeling tussen weidiere was duidelik herkenbaar in die warm, droë seisoen. Herbivoor verspreiding is meestal geassosieer met die afstand na die water, die grasveld hoogte, tydperk sedert ‘n brand, digtheid van houtagtige plantsoorte en met die teenwoordigheid van die oorheersende grasse, Urochloa mossambicensis, Panicum maximum, Heteropogon contortus en Digitaria eriantha. Die ekologiese skeiding van herbivore deur die grasse P. maximum, H. contortus en D. eriantha het meer gedui op geassosieerde omgewingsveranderlikes as op skeiding van voedingsnisse. ‘n GIS-gebaseerde analise wat spesie-teenwoordigheidsdata en kwantitatiewe dekking van omgewingsveranderlikes gebruik, het klassifikasiekaarte geproduseer van habitatgeskiktheid vir weidiere tydens die droë seisoen. Resultate van beide analises is geïntegreer en het ‘n beter begrip van ekologiese skeiding en moontlike kompeterende interaksies tussen die groot herbivore gemeenskap op Malilangwe Estate tot gevolg gehad. Aanbevelings is gemaak, gebaseer op die interpretasie van bevindinge, binne die konteks van beskikbare bestuursopsies.
AFRIKAANSE OPSOMMING: Die bepalende faktore van habitat seleksie by groot herbivore op ‘n privaat wildreservaat in semi-dorre suidoos Zimbabwe is ondersoek. Globale plantegroei stuktuur, kruidagtige samestelling en topografiese eienskappe wat glo herbivoor verspreiding bepaal, is gemeet. Seisoenale variasie in hulpbronverspreiding is in ag geneem en dus het navorsing oor ‘n hele jaar gestrek. Herbivoor verspreiding en ekologiese nisskeiding is verduidelik deur verskeie belangrike omgewingsveranderlikes en die potensiaal vir interspesifieke kompetisie is afgelei. Boonop is voorspellende habitat-geskiktheidsmodelle ontwerp vir elk van die weidingspesies in die krities droë seisoen. Herbivore toon ‘n hoë graad van nis oorvleueling in sowel die warm, nat seisoen as die koel, droë seisoen wanneer voedingsbronne meer volop is. Nis verdeling tussen weidiere was duidelik herkenbaar in die warm, droë seisoen. Herbivoor verspreiding is meestal geassosieer met die afstand na die water, die grasveld hoogte, tydperk sedert ‘n brand, digtheid van houtagtige plantsoorte en met die teenwoordigheid van die oorheersende grasse, Urochloa mossambicensis, Panicum maximum, Heteropogon contortus en Digitaria eriantha. Die ekologiese skeiding van herbivore deur die grasse P. maximum, H. contortus en D. eriantha het meer gedui op geassosieerde omgewingsveranderlikes as op skeiding van voedingsnisse. ‘n GIS-gebaseerde analise wat spesie-teenwoordigheidsdata en kwantitatiewe dekking van omgewingsveranderlikes gebruik, het klassifikasiekaarte geproduseer van habitatgeskiktheid vir weidiere tydens die droë seisoen. Resultate van beide analises is geïntegreer en het ‘n beter begrip van ekologiese skeiding en moontlike kompeterende interaksies tussen die groot herbivore gemeenskap op Malilangwe Estate tot gevolg gehad. Aanbevelings is gemaak, gebaseer op die interpretasie van bevindinge, binne die konteks van beskikbare bestuursopsies.
Description
Thesis (MFor)--University of Stellenbosch, 2003.
Keywords
Herbivores -- Habitat -- Zimbabwe, Southeastern, Habitat selection, Habitat partitioning (Ecology) -- Zimbabwe, Southeastern, Resource partitioning (Ecology) -- Zimbabwe, Southeastern, Theses -- Forest and wood science, Theses -- Conservation ecology and entomology, Dissertations -- Forest and wood science, Dissertations -- Conservation ecology and entomology