Abstract:
In 1991 five giraffe (Giraffa camelopardalis) were introduced to the Vaal Spa Nature Reserve three kilometres north of Christiana. A project was undertaken to monitor their adaptation in the new habitat and to assess the suitability of the habitat for sustaining a giraffe population. The soil form in the bigger part of the study area is a Bainsvlei form. Plant communities occurring in the study were identified by using Braun-Blanquet methodology. A TWINSPAN classification, further refined by Braun-Blanquet procedures resulted in four plant communities : Acacia karroo - Cynodon dactylon short thicket. Rhus lancea - Enneapogon scoparius low thicket. Acacia tortilis - Eragrostis rigidior open woodland. Eragrostis rigidior - Schmidtia pappophoroides sparse woodland. A study to monitor the feeding strategy of the giraffe was undertaken over a period of three years. It was established which of the plant species the giraffe selected and the relative importance of each species was determined. It was established that Acacia tortilis is favoured as a fodder plant, followed by Ziziphus mucronata. Samples of the preferred plant species in the Vaal Spa Nature Reserve was taken over a one year period. It was analysed for moisture content, ash content, protein content, crude fibre content, fat content, phosphate content, calcium content, digestable fibre and energy content. The same samples were used in determining each species' in vitro digestibility. The experiments were conducted with the rumen liquids of njala in the Kruger National Park. The fermentation rates within the rumen and ceacum of a giraffe were compared. It was found that the giraffe adapted well to their new environment in spite of harsh environmental conditions like below average rainfall during the study period. It was found that the giraffe in the Vaal Spa Nature Reserve select their browse on grounds of availability, and not according to chemical composition. Proposals were made towards to the management of the giraffe population.
