Browsing behaviour of impala, Aepyceros melampus in two contrasting savannas

Impala are medium-sized antelopes, widely distributed throughout East and Southern Africa. They consume grasses in the wet season, switching to browsing in the dry season. African savannas are classified into arid-eutrophic and moist-dystrophic. The arid-eutrophic savannas have fertile soils which support plant biomass of high nutritive value, utilised by small and mediumsized herbivores. The moist-dystrophic savannas have nutrient-poor soils and high plant biomass of relatively low nutritive values, utilised by large-bodied herbivores. Impala occur in both savannas, though more abundant in the arid-eutrophic savannas. I studied browsing behaviour of impala in Mikumi National Park, a moist-dystrophic savanna, and Serengeti National Park, an arid-eutrophic savanna. A car was driven in all access roads in the Parks during the wet and the dry season. The car was stopped for recording whenever impala were sighted browsing within 50 m from the road. I recorded tree species browsed, browsing height, number of bites, and habitat type. The study showed differences between the seasons and the savannas. The animals took more bites during the dry season compared to the wet. Biting rate was higher during the dry season and when spineless trees were utilised. Small and large leaves reduced biting rate while medium size leaves promoted biting rate. The impala frequently browsed at head level in both savannas, however variations between the savannas were observed during the wet season. The differences in forage quality and quantity between the savannas and the seasons, and in herbivore community between the savannas are likely to attribute the results.

Automated summary

The study showed differences in browsing behavior of impala between seasons and savannas, with impala taking more bites in the dry season and biting faster when browsing spineless trees. Additionally, browsing small leaves and large leaves decreased biting rate while medium size leaves promoted biting rate. Variations in browsing behavior between savannas were observed during the wet season.