Seasonal nutrient fluctuation in selected plant species in the Kalahari

Seasonal changes in crude protein, phosphorus and calcium contents of five common plant species in the south-western Kalahari were investigated. Three species that are browsed by springbok (Acacia erioloba, Grewia flava and Rhigozum trichotomum) and two grass species (Schmidtia kalahariensis and Stipagrostis obtusa), were included in the study. Browse species had higher crude protein, phosphorus and calcium contents than the grass species, but the fluctuation range was similar to that of the grass species. In general, the crude protein content of the food plant species sampled in the present study was above the level required by African ungulates for maintenance. However, the diet of springbok in the south-western Kalahari appeared to be phosphorus deficient. Crude protein and phosphorus levels in plant food were especially low during the cold-dry season, when the crude protein content of the grass species was at or below that which is required by springbok for sustenance. The phosphorus content was below...