 Reference Base  Resource partitioning between the five major grazing ungu... |
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Emslie, R.H., 1985. Resource partitioning between the five major grazing ungulates in the Umfolozi Game Rserve, Natal. South African Journal of Science 81: 698-699
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| Location: |
Africa - Southern Africa - South Africa |
| Subject: |
Ecology - Food |
| Species: |
White Rhino |
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Umfolozi, South Africa - resource partitioning. The degrees of dietary separation between white rhinoceros, buffalo, zebra, wildebeest and impala were examined in the 1983/84 wet season in an attempt to shed some light on how these species coexist. Feeding patches were defined (using a 0.25 m? circular quadrat) and an assortment of techniques were used to measure what was available, what had been eaten and how it had been eaten. These ranged from broad-scale measurements of all grass species to detailed measurements of every tiller of two key species, Themeda triandra and Panicum coloratum. These data were then analysed according to a hierarchy of selection (feeding patch, species, tiller size and plant part selection).
Only buffalo selected areas dominated by culmed T. triandra (which contributed 59% of their diet).The four other species selected areas where 'short and medium' species contributed between 75% and 90% of the standing biomass. These grazers demonstrated highly significant species selection within short grass areas. Even when grazing the same species, tiller size selection differed between ungulates. Taking P. coloratum as an example, the broad-mouthed 'lawn mower' species (wildebeest and white rhinoceros) preferentially grazed the shorter, erect central tillers on a tuft, while the longer, stoloniferous tillers contributed significantly to the diet of the narrower-muzzled and more selective impala and zebra. These data indicated that the main scale of selection was at the feeding patch level, while selection for species and tiller size within patches further increased dietary separation. Different digestive systems, body sizes and mouthparts enabled grazers to exploit the large degree of macro- (area, batch) and micro- (species, tiller size) habitat heterogeneity and allow widely differing feeding niches to be adopted, thus enabling coexistence to occur. Dietary overlap would, however, be expected to increase during the dry season.
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