Patterns of association, nestedness, and species co-occurrence of helminth parasites in the greater kudu, Tragelaphus strepsiceros, in the Kruger National Park, South Africa, and the Etosha National Park, Namibia

The helminth parasites of the greater kudu from the Kruger National Park (KNP), South Africa, and the Etosha National Park (ENP), Namibia, were examined to determine the major patterns of spatial and demographic variation in community structure and to evaluate nonrandomness in parasite community assembly. Nonmetric multidimensional scaling ordination procedures were used to test for differences in parasite community composition between hosts of the 2 parks and between hosts of different demographic groups within KNP. Infracommunities within KNP were also examined for patterns of nonrandomness using 2 null models, i.e., nestedness and species co-occurrence. Infracommunities of KNP and ENP were significantly different from each other, as were infracommunities of different host demographic groups within KNP. Parasite species in the greater kudu from KNP displayed significant levels of nestedness and were found to co-occur less frequently than expected by chance; however, this lack of co-occurrence was significant only when all demographic groups were considered. When restricted to any particular age class, co-occurrence patterns could not be distinguished from random. Overall, these data suggest that biogeography and host demographics are important factors in determining community organization of helminth parasites in the greater kudu.     

Food habits of giraffe in Tsavo National Park, Kenya

In the context of a broader ecological investigation, food habits of giraffe were studied in Tsavo National Park (East). The only method employed was direct observation of feeding animals in the field. Each instance in which one animal fed on one individual plant was counted as one food record for this plant species; 4025 records are analysed. A total of sixty-six plant species was found to be eaten, the great majority being trees and shrubs, with a few creepers and vines. There were marked seasonal differences in the diet of giraffe, deciduous trees, shrubs and vines being dominant in the green season, evergreen plants (partly in riverine forest) in the dry season. All the trees and larger shrubs common in the study area were eaten by giraffe, while few records for very small shrubs and none for herbs and grasses were obtained. An analysis of the available vegetation was made in part of the dry-season habitat, and for twenty species the frequency in the habitat was compared with the frequency in the giraffe's diet, revealing selection for or against certain species. Giraffe utilized the upper vegetation layers, where available, but overall c. 50% of all browsing was below 2 m above ground, i.e. within reach of smaller browsers. Results of this study are compared with what is known on food habits of giraffe in other areas. Possible competition of giraffe with other browsers and the relationship between giraffe and their habitat are discussed. Continued survival of giraffe, and other browsers, in Tsavo National Park depends primarily on (1) adequate control of fire, and (2) the impact of future vegetation changes on the amount and variety of available browse plants.     

Habitat selection by large herbivores in Lake Nakuru National Park, Kenya

The overall density of 17 large herbivore species encountered during the study differed among species and habitat types, but not between seasons. There were clear seasonal patterns of association among species, which were more pronounced during wet than dry seasons, suggesting greater habitat selectivity and increased ecological separation. The defassa waterbuck (Kobus ellypsiprymnus defassa Ruppel) showed ecological separation from other species, possibly because it competitively displaced them.     

Preliminary observations on the daytime activity patterns of lesser kudu in Tsavo National Park, Kenya*

Free-ranging lesser kudu were observed during the day in Tsavo (East) National Park for periods of up to 12 h and records of activity patterns were obtained. Data grouped into the percentage of animals engaged in feeding, resting, and other activities in each time class show a changing pattern of behaviour through the day. The presence of a biphasic resting rhythm is demonstrated, the initiation and duration of which are variable. Feeding generally predominated in the early morning and late afternoon. Rumination took place during resting periods which were also used for the avoidance of excessive heat stress. Possible factors controlling the phasing of the behaviour seen are discussed.     

Drought mortality of bush elephants in Hwange National Park, Zimbabwe

African bush elephants inhabiting the undeveloped Kalahari Sands region of Hwange National Park, Zimbabwe are subject to episodic mortality during droughts. We monitored the drought‐related mortality of elephants in Hwange National Park over the course of an extended drought between 1993 and 1995. The drought‐related mortality of elephants was higher during 1994 than 1995, despite significantly higher rainfall in 1994 than 1995. We found significant differences in the age‐specific mortality of elephants during 1994 and 1995. The cumulative mortality profile from this study differed significantly from previous die‐offs at this site, with a higher mortality among adult age classes than that reported from earlier studies in Hwange National Park. The effective duration of the rainy season, not total annual precipitation, appears to be the best predictor for the potential severity of drought mortality among elephants in the Kalahari Sands habitats of Hwange National Park.