Woodland loss and restoration in a savanna park: a 20-year experiment
Woodland loss is a major cause of biodiversity decline in African savanna parks. Decisions about whether remedial steps are possible and warranted depend on the cause. Climate, fire, elephants and human impact, often in combination, have been cited as major causes. The almost complete extinction of woodland in Amboseli National Park since 1950 has been […]
Herbivore population crashes and woodland structure in East Africa
Between 1985 and 1991, bush encroachment was serious in Lake Manyara National Park, northern Tanzania. Shrub cover increased by c. 20%. The increase was independent of initial (1985) shrub cover. Since 1987 there has been a steep decline in the number of African elephant in the Park due to poaching. Elephant density decreased from about […]
The giraffe and its food resource in the Serengeti. I. Composition, biomass and production of available browse
The quantification of the browse resource available to giraffe was undertaken as the first stage in the study of the relationship of the giraffe population and its food supply in the Serengeti woodlands. Techniques are described for estimating the seasonal standing crop biomass of available browse and its quarterly rate of production. The conversion of […]
Feeding behaviour of giraffe Giraffa camelopardalis in the Willem Pretorius Game Reserve, Orange Free State
The habitat and feeding behaviour of giraffe in the Willem Pretorius Game Reserve, Orange Free State, are described. Acacia karroo, the single most important component, together with Asparagus laricinus, Rhus undulata and Ziziphus mucronata, comprises almost 90% of the giraffe’s diet. During the wet season deciduous plants of the savanna flats are preferred, but in […]
Effects of simulated shoot and leaf herbivory on vegetative growth and plant defense in Acacia drepanolobium
Plants have considerable ability to respond to herbivory, both with (above-ground) regrowth and with increased defense. We simulated both leaf and shoot herbivory in controlled, replicated experiments on individuals of Acacia drepanolobium in Laikipia, Kenya. These experiments were carried out on individuals that had experienced different, experimentally controlled histories of large mammalian herbivory. Both forms […]
Detection and characterisation of papillomavirus in skin lesions of giraffe and sable antelope in South Africa
Papillomavirus was detected electron microscopically in cutaneous fibropapillomas of a giraffe (Giraffa camelopardalis) and a sable antelope (Hippotragus niger). The virus particles measured 45 nm in diameter. Histopathologically, the lesions showed histopathological features similar to those of equine sarcoid as well as positive immunoperoxidase-staining of tissue sections for papillomavirus antigen. Polymerase chain reaction (PCR) detected […]
Effects of natural and simulated herbivory on spine lengths of Acacia drepanolobium in Kenya
We present experimental evidence supporting the hypothesis that increased spine length in acacia species is a defense induced by herbivory. Acacia drepanolobium is the dominant tree over large areas of East Africa. Each individual tree is occupied by one of four ant species at our study site. Using two types of electric fences, we have […]
Shoot characteristics of Acacia tortilis (Forsk.) in wildlife and rangeland habitats of Botswana
Length, branch production, orientation, spinescence and biomass were measured for current shoots of Acacia tortilis shrubs in a range of habitats in Botswana. All shoot characteristics varied between individuals and between habitats with longer, less spinescent shoots produced in the habitat recently protected from wildlife. Biomass allocated to woody material increased with shoot length at […]
The impact of giraffe, rhino and elephant on the habitat of a black rhino sanctuary in Kenya
The habitat in an enclosed black rhino sanctuary, the Sweetwaters Game Reserve in Kenya, is being altered as populations of elephant, giraffee and black rhino increase. Height-specific browse impact data were recorded for 1075 trees of the dominant species, the whistling thorn, Acacia drepanolobium. Rhinos and elephants browsed 18% of these trees in 1 year, […]
Food Consumption and Energy Budgets of the Giraffe
(1) To estimate the efficiency of the foraging strategy described in Pellew (1984), the rates of food intake of adult giraffe in the Serengeti National Park are assessed. Daily energy intakes derived from the diet are compared with estimates of the energy requirements for year-round reproduction. The reproductive performance of giraffe in the Serengeti is […]