Wag-ân-Bietjie Private Nature Reserve is situated ±30 km north of Bloemfontein in the summer
rainfall area. The northern part is 437 ha in size and represents a transition between grassland and
riparian vegetation. Vegetation types present are grassland, open thickets, dense thicket, drainage
lines of the Modder River, a wetland and disturbed area.
Phenology (seasonal leaf carriage) of plants formed the basis of this study. Percentage leaves in
each phenophase (Budding-, Immature-, Mature-, Yellow- and Dry leaves) was noted fortnightly
for specific marked trees and shrubs representing each vegetation type. The deciduous nature of
woody species influenced quality and quantity of browse available for herbivores. Consequently the
nitrogen concentration in faeces (Nf) of four game species was determined to indicate their
nutritional status through the different seasons. The rise and fall of Nf values corresponded to the
seasonal increase and decrease of leaves (phenology pattern). Nf ranged during four years from 18 â
37 gN/kgDM for giraffe, 14 â 33 g/kg for kudu, 16 â 35 g/kg for eland and 17 â 28 g/kg for impala.
Abovementioned minimum concentrations are close to, and in the case of kudu below known
critical values where animals start to lose body condition. Nitrogen is the most limiting nutrient in
the dry, cool season and is linked to protein percentage present in browse. Browse becomes a
limited resource in the winter, therefore certain game species moved seasonally to different areas
inside the private reserve in search of food. It was decided to supply feed in order to sustain animals and help them maintain body condition during the critical period that was established to be from
July/August to middle October. The duration of feeding is important and it is recommended to start
feeding from July at a low ration and then gradually increase feed towards the end of the critical
period in correspondence with the declining browse and grass resources.
Average monthly leaf carriage percentages were used to calculate browsing capacity per month in
each vegetation type and in the study area as a whole. Browser units that could be sustained on
browse resources within the 0 â 2 m stratum ranged from 1 â 6.7 BU between winter and summer
due to the deciduousness of all woody plants present in the study area. This justifies in some way
the provision of feed, or else the numbers of animals would need to be reduced to 1 BU which does
not represent sustainable populations. Viable population numbers, economic value, diet and
reproduction rates were used in determining the numbers of individual animals that can be stocked.
Grazing capacity of the area differed according to annual rainfall and increased with higher rainfall.
Consequently it needs to be recalculated annually.
Habitat occupied by all 17 herbivore species was determined. Some species did not historically
occur in the province. Most of them have adapted to the central Free State conditions over time,
while others were introduced more recently. Inter-species competition for space and food resources
proved to be high in the study area. A reduction in animal numbers has been recommended to limit
competition.
There is an ever increasing number of private game ranches in the province, >343 in August 2010,
that will benefit from this research. Some general, operational guidelines have been presented that
are applicable to the management of other game ranches in the province as well. When calculating
individual animal numbers equivalent to carrying capacity values of other areas, the percentage
grass and browse that herbivores include in their diet need to be adjusted to the specific area for
accurate stocking densities.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:ufs/oai:etd.uovs.ac.za:etd-03132013-091959 |
| Date | 13 March 2013 |
| Creators | Janecke, Beanélri Bénene |
| Contributors | Prof GN Smit |
| Publisher | University of the Free State |
| Source Sets | South African National ETD Portal |
| Language | en-uk |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.uovs.ac.za//theses/available/etd-03132013-091959/restricted/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to University Free State or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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