Assessing the effects of grazing intensity by large herbivores on species diversity and abundance of small mammals at Waterberg Plateau Park, Namibia

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2007
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This study focused on the effects of disturbance by large herbivores on the species diversity of small mammals at Waterberg Plateau Park in northern Namibia. The effects of large herbivores on species diversity (species richness and eveness) and composition were investigated in the vicinity of two waterholes, Duitse Post and Securidaca. At each watering point, two sites along the rangeland utilization gradient, at 100 m and 2 km distance from waterhole, were selected. The sites situated at 100 m from a waterhole, fall under a more disturbed area, whereas sites located at 2 km distance lie in the less disturbed area. A total of 100 trap stations, spread into a 1 ha (100 x 100 m) grid were placed at the two interval distances from the waterhole. The Sherman traps, along with the capture-mark-recaptured method were employed
The Kruskal-Wallis test (H = 12, df = 4, p = 0.916) indicated that there was no significant difference in the vegetation cover between the more disturbed and less disturbed area, particularly at Duitse post waterhole. The Mann-Whithney U test (U 1.0. p = 0.015) indicated that there was a significant difference in the vegetation cover between the more disturbed and less disturbed area at Securidaca waterhole, A total of 146 individual small mammals, representing 12 species, were captured in 8000 trap nights. Dendromus melanotis was most commonly captured small mammal species followed by Gerbillurus paeba, Tatera leucogasier and Thallomys nigricauda being the least captured The study revealed that species diversity was high in the more disturbed area, while species richness and composition was high in the less disturbed area
The encountered high proportion of Mastomys spp and reduction of population density of Tatera leiicogaster suggests a level of disturbance in the more disturbed areas, The Petersen method of capture-mark-recapture showed that there was no significant difference in population density of small mammals (U = 10.0, p = 0.602) betweenthe more disturbed and less disturbed area. Minimum Number Alive (MNA) methodshowed that there was no significant difference in population size of small mammals (U = 62.5, p = 0.579) between more disturbed and less disturbed area.The present study was the first to record Dendronms melanotis at Waterberg Plateau Park.
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Submitted in partial fulfilment of the requirements for the degree of Master of Science in Biodiversity Management and Research in collaboration with Humboldt-Universität zu Berlin
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