Forage quality and availability for large herbivores in southern African rangelands

Abstract

In light of the growing human population, the pressure on herbivores (livestock and wild herbivores) will be accelerated, resulting in a need for eff ective land management. To achieve this, information and knowledge about the availability and quality of food resources of large herbivores and possible changes in those resources are a prerequisite. In this chapter, we wil l summarize diff erent projects conducted regarding food availability and quality within SASSCAL. We will give an example of the use of remote sensing as an eff ective tool for measuring food availability and quality on a large scale. Here, we visualize changes in leaf nitrogen concentration and annual grass biomass. In two other projects, we studied diff erent aspects of plant response. In a fence-line study, we investigated the infl uence of overgrazing on the plant quality of grasses. Though we detected positive impacts on plant quality, but due to high grazing pressure, the reduction in biomass resulted in an overall decline in the quality of the overgrazed site. In the other project, we tested the plant response of bush encroacher species to damage by herbivores. In contrast to the grasses of the fence-line study, in the shrub species we observed a tendency for reduced protein concentration. The reduction varied among the diff erent plant species, but it did not have consequences on subsequent consumers (Boer goats). In our last project we focused on the impact of increased temperature and reduced humidity on the plant quality of fi ve grass species. Here, we found a species-specifi c response. We conclude the article with a synthesis and an outline of possible management implications derived from the diff erent studies.