Diet selection and habitat selection is closely related, since the availability of food is one of the main determining factors in the acceptability of the habitat for the wild animal. Diet selection can be determined through visual observations of a game species, while certain measurements of the food plants and the collection of plant material are also necessary. Since visual observations are made, certain aspects of social behaviour are usually also included in a diet selection project.

Diet selection can include the determination of the following aspects:

• Availability of palatable food plants in total and at different feeding heights (BECVOL model for browsers);
• Carrying capacity (number of animals that can be sustained on the available food);
• Preferred food plants of wild animals;
• Presentation utilisation of individual plants;
• Factors that influence utilisation;
• Nutritional status of animals (determined through faecal nitrogen analyses);
• Intra- and inter-species competition between animals, etc.

Projects

1. Habitat and feeding ecology of the kudu.
Project leader: Dr BB Janecke
Various aspects are being examined that have relevance to the feeding, diet selection, and habitat preferences of the kudu. This forms part of a master's degree study.

2. Nutritional status from faecal nitrogen
Project leader: Dr BB Janecke
Nitrogen in faeces of wild animals is determined monthly. It indicates differences between seasons that can be connected to phenology percentages (leaf carriage) of deciduous trees. In literature, certain values are available that indicate the critical levels of faecal nitrogen where animals lose body condition or mortalities may occur. In this way, the nutritional status of the animal can be determined. Faecal nitrogen can also be connected to crude protein quantities in the droppings. These values have already been determined for kudu, giraffe, eland, and impala, while other browsing game species are also in the process. Fresh faeces are collected, dried and milled, where-after nitrogen content is determined in a laboratory with the Leco Nitrogen Analyser.

3. Phenology (leaf carriage patterns) of trees and shrubs
Project leader: Dr BB Janecke
Deciduous trees are usually the main food source for browsers. During winter, a critical period of limited browsing may occur when these trees are leafless. Evergreen plants, which are less palatable, are usually included in the diet during winter. In order to calculate the correct carrying capacity of game ranches and nature reserves, the quantity of food that is available during winter to sustain the animals must be the determining factor. Thus, the determination of phenology, indicating the critical period, is of cardinal importance. An estimating method has been developed to determine phenology, and is being applied to different plant species in different areas through the seasons.

4. Tannins and secondary metabolites
Project leader: Dr BB Janecke in collaboration with Dr ME Cawood (Plant Sciences)
Plants have specific defence mechanisms that protect them to a certain degree against browsing. One of the chemical defence mechanisms is the increase of tannin and other secondary metabolite levels in the plant. Tannins are chemical compounds that reduce the digestibility of proteins in leaves. Tannin concentrations are determined in a laboratory. A series of experiments are being conducted to determine how tannin levels change under certain circumstances.

5. Habitat and feeding ecology of the nyala
Project leader: Dr BB Janecke
This project follows the same methods and procedures as the project on kudu. Competition between these two browsers of the same genus (Tragelaphus) is being examined. The nyala is native to KwaZulu-Natal and thus forms part of the project to determine how this species adapt to conditions in the Free State.