This study focused on how changes in food availability during the dry season,
influenced various aspects of sable (Hippotragus niger niger) foraging and social
ecology. The main purpose of this was to determine whether differences in their
foraging ecology explained the reduction in population size compared to other
more abundant herbivores (e.g. zebra, buffalos, hartebeest).
Contrary to expectation, sable did not limit their foraging to woodlands, but
also fed in open grasslands, provided these retained green grass during the dry
season. Wetlands were key resource areas during the dry season, but sable did not
limit their feeding to these bottomland areas. They also fed on hill slopes and
upper plateaus that had been burnt. During the study, sable were attracted to burnt
areas despite the reduced grass availability. My study highlights how these burnt
areas were important in alleviating nutritional deficiencies during the dry season.
At lower spatial levels, I looked at the factors that influenced the selection of
feeding areas and plant species. Like other grazers, sable were attracted to green
leaves but did not avoid brown leaves or stems. Grass species eaten were the same
as those preferred by most domestic and wild grazers.
Surprisingly, adult males stayed with the breeding herds despite their different
activity budgets. Unlike most other African grazers, sub adult sable males did not
form bachelor groups. Instead, they stayed within the breeding herds the whole
time and had a similar activity budget to females. As adult males moved with the
breeding herds, I was able to examine the costs and benefits involved with such a
social structure. From this, I was able to relate my results to the bigger picture of
factors influencing sexual segregation in ungulates.
In conclusion, sable utilised a wide variety of habitat types and adjusted their
foraging behaviour to accommodate different seasonal situations. I was unable to
find anything in their feeding ecology that could explain the continued decline in
population size. Therefore, I suggest that future research needs to focus on other
potential causes such as a higher susceptibility to predation and disease as
compared to more abundant herbivore species.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/5695 |
| Date | 26 September 2008 |
| Creators | Parrini, Francesca |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf |
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