Modelling the impact of large herbivores on the food supply of mountain gorillas and implications for management Original Research Article

During the 1980s, the populations of large mammals, particularly buffalo Syncerus caffer, appeared to be increasing in the Virunga volcanoes in central Africa, causing concern about their possible impact on the food supply of the mountain gorilla Gorilla gorilla beringei. This was therefore investigated by analysing the overlap in diets and habitat use between the mountain gorilla population and four other large mammalian herbivore populations. Expected niche overlap values were calculated from random simulations and showed that dietary overlap was unexpectedly low between most speciesʹ pairings. Predictions about the effects of competition on the five herbivores were produced by computer simulation of the plant-herbivore dynamics. These showed that elephants Loxodonta africana could have the most serious effect on the gorilla population. The other herbivores would appear to have little effect on the food supply. Consequently further increases in the buffalo population should cause little concern for the gorilla population. The conservation of the mountain gorilla is discussed in the light of these findings.