Date of Award:

5-1986

Document Type:

Dissertation

Degree Name:

Doctor of Philosophy (PhD)

Department:

Wildland Resources

Department name when degree awarded

Fisheries and Wildlife

Committee Chair(s)

Frederic H. Wagner

Committee

Frederic H. Wagner

Abstract

Coexisting ungulate-eating carnivores--lion, spotted hyena, cheetah, leopard, African wild dog, black-backed jackal, common jackal, and six species of vulture--are examined in East Africa's Serengeti ecosystem. Niche similarities year-round, by season, and by location are described using food, habitat, time of hunting, and other variables. Intraspecific niches of cheetah sex, age, and social groups show that male coalitions differ most from the others in hunting behavior and habitat use. Tests using the carnivore data failed to support hypotheses about niche breadth variation, niche overlap variation, range of food items, and niche inclusion. Densities of the five largest Carnivora in the 35,500 square kilometer ecosystem are 0.513/sq km; including the two jackals gives a density of 1.55/sq km. Their prey--30 ungulate species--are 84.85/sq km. Prey and predator ratios suggest that the Serengeti Plains in 1977 had a three-fourths decrease in relative abundance of prey to predators from wet season to dry season. Year-round the Ngorongoro Crater had a prey:predator ratio slightly larger than that of the dry season Serengeti Plains. Literature review suggests that cleptoparasitism and direct killing are very important forms of interference competition among and within carnivore species. Evidence for exploitation competition is scant, but is inferred because local environments are unpredictable for carnivores. Analysis of body sizes fails to support the hypothesized ratios of 2.0 for body weight and 1.28 for linear dimensions. Three methods of calculating multidimensional niche metrics (product, summation, and projection) are compared. Apparently the Serengeti's carnivores coexist because of their behavioral flexibility in an unpredictable environment. Niche descriptions were of little help in assessing the foci for potential and real competition among carnivores. Only the direct observations of interference competition in long-term field studies identified where competitive interactions are occurring with sufficient intensity to provide a numerical response in a population. Spotted hyenas sometimes competitively exclude African wild dogs locally. Management for a high abundance and diversity of carnivores probably requires maintaining high densities of prey and varied habitats. Specific recommendations are made for cheetah and African wild dog conservation.

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