Variations in Patch Use by Ruminant and Non-Ruminant Herbivores in a Tropical Wildlife Reserve, Ghana

Abstract

Food processing and consumption by herbivores are affected differently by the availability of forage quality and quantity per unit of time. This demonstrates the “Allometric response concept”, and it is considered a significant determinant in habitat use for foraging by grazers. The relevance of this approach has comprehensively been applied to herbivores of different body sizes, but little is known about its demonstration to explain patch use in herbivores with different digestive physiology and body size. We explain the use of patches by grazing herbivores of different digestive physiology and body sizes, Hippopotamus amphibius (hippopotamus, mega non-ruminant) and cattle (ruminant), by integrating foraging relationship herbivores. We analysed the significant relationships between species dropping densities and environmental variables across forty-eight 100 m×100 m plots in Bui National Park, Ghana, during the wet and dry seasons. We found that both species utilised areas closer to the river in the wet season, but the H. amphibius foraged further away from the river during the dry season. Sward height also determined patch use by both species, with the H. amphibius utilising shorter swards than the cattle. Considering the quality of food resources, the study revealed that patch selection of ruminants (cattle) was significantly influenced by nitrogen content. In contrast, acidic detergent fibre content was positively related to non-ruminant species (H. amphibius). The high seasonal effect of sward height and food quality on patch use is primarily due to the species digestive physiology and body size of hippopotamus and cattle at the Bui National Park.