Population, distribution, and behaviour of giraffe in the Arusha National Park, Tanzania
In a year’s study of the giraffe population of the Arusha National Park we identified 462 individuals. The cumulative first sightings of individuals were fitted to a logistic model that gave an estimated total population of 471. Immatures accounted for only 24% of the population. Twenty-two calves were born during the period of study. The […]
Seasonal utilization of leaves by giraffes Giraffa camelopardalis, and the relationship of the seasonal utilization to the chemical composition of the leaves
Food preferences of giraffe have been extensively investigated but few data concerning the chemical composition of the preferred species are available. The present study was aimed at ascertaining whether the differences in chemical composition of leaves of preferred food plants influence food selection. Furthermore, whether there are differences in the chemical composition of the specific […]
A comparison between Acacia and Combretum leaves utilized by giraffe
Various studies on the food preferences of giraffe indicate that the leaves of the Acacia and Combretum species are the most important food items selected. The present study was aimed at comparing the chemical composition of the leaves and explaining the utilization of both these plant groups by giraffe. The protein content of the leaves […]
The feeding behaviour of giraffe in Niger
The remaining West African giraffes (Giraffa camelopardalis) are found in Niger (62 individuals in January 1998). Their feeding behaviour was studied by direct observation during two periods of 6 and 12 mo. The giraffe’s diet is diverse: at least 45 plant species were eaten, depending on spatial arrangement and a given plant’s stage of growth. […]
Female tannin avoidance: a possible explanation for habitat and dietary segregation of giraffes (Giraffa camelopardalis peralta) in Niger
Niger is host to the last free‐roaming herd of G.c. peralta (Giraffa camelopardalis peralta). We examined the foraging preferences of these giraffe in their dry‐season habitats, with the goal of preserving the herd in the regions that they currently inhabit. The current dry‐season habitat comprises two distinct vegetation zones. In both of these zones the […]
Symbiotic ants as an alternative defense against giraffe herbivory in spinescent Acacia drepanolobium
We explore here the occurrence of aggressive ants in an apparently symbiotic relationship with the savanna tree Acacia drepanolobium and their effects on giraffe herbivory on the Athi-Kapiti Plains, Kenya. Trees taller than 1.3 m were more likely to be occupied by aggressive ants in the genus Crematogaster than were shorter trees. Ants were concentrated on shoot tips, the […]
Browsing-induced Effects on Leaf Litter Quality and Decomposition in a Southern African Savanna
We investigated the linkages between leaf litter quality and decomposability in a savanna plant community dominated by palatable-spinescent tree species. We measured: (1) leaf litter decomposability across five woody species that differ in leaf chemistry; (2) mass decomposition, nitrogen (N); and carbon (C) dynamics in leaf litter of a staple browse species (Acacia nigrescens) as […]
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, […]