Browsing Lawns? Responses of Acacia Nigrescens to Ungulate Browsing in an African Savanna
We measured browsing-induced responses of Acacia trees to investigate ‘‘browsing lawns’’ as an analogy to grazing lawns in a semiarid eutrophic African savanna. During the two-year field study, we measured plant tolerance, resistance, and phenological traits, while comparing variation in leaf nitrogen and specific leaf area (SLA) across stands of Acacia nigrescens, Miller, that had […]
Behaviour and the effect of giraffe on flora
The study has taken place in Etosha National Park whereby the behaviour and effect of giraffe on the flora was considered. The population of Etosha giraffe is a about 1800, which is high in the presence of other browsers. A lot of trees are pressurized by giraffe and a lot of individual tree spp are […]
Resource partitioning within a browsing guild in a key habitat, the Chobe Riverfront, Botswana
Resource partitioning between elephant, giraffe, kudu and impala was assessed. This was to address concerns that elephant population increase adversely affects other species through depleting their food in key areas close to permanent water. Resources considered were woody species browsed, height browsed and plant parts browsed. Animals were observed as they browsed and the plant […]
Interactions between large African browsers and thorny Acacia on a wildlife ranch in Kenya
Some plants respond to browsing with compensatory regrowth of plant tissues and with increased thorn growth. Associations between browsers and their preferred forage were examined through wandering quarter vegetation sampling and observational studies in an effort to understand how some plants respond to browsing by large African herbivores. Acacia seyal (n = 2680) A. drepanolobium […]
Not all ants are equal: obligate acacia ants provide different levels of protection against mega-herbivores
In obligate ant–plant mutualisms, the asymmetric engagement of a single plant species with multiple ant species provides the opportunity for partners to vary in their behaviour. Variation in behaviour has implications for the interactions with third-party species such as herbivores. This study assessed the effect of obligate ant mutualists (Crematogaster mimosae, Crematogaster nigriceps and Tetraponera […]
Sex differences in giraffe foraging behavior at two spatial scales
We test predictions about differences in the foraging behaviors of male and female giraffes (Giraffa camelopardalis tippelskirchi Matchie) that derive from a hypothesis linking sexual size dimorphism to foraging behavior. This body-size hypothesis predicts that males will exhibit specific behaviors that increase their dry-matter intake rate relative to females. Foraging behavior was examined at two […]
Effect of low rainfall and browsing by large herbivores on an enclosed savannah habitat in Kenya
Savannah ecosystems in East Africa are rarely stable and can experience rapid local changes from dense woodlands to open plains. In this 3-year study there was a reduction of 16.3% in a height-stratified sample of nearly 1000 individually marked Acacia drepanolobium trees. The study was carried out in an enclosed fire-free wooded grassland habitat in […]
Regrowth and palatability of acacia shoots following pruning by African savanna browsers’
Stands of two species of African Acacia were monitored for 1 yr in a natural savanna ecosystem, to compare shoot regrowth and leaf chemistry in lightly browsed and heavily browsed trees. Where ungulates concentrated at a seasonal waterhole, A. nigrescens was more severely browsed than the thornier and finer leafed A. tortilis. Shoot regrowth in […]
The maximum attainable body size of herbivorous mammals: morphophysiological constraints on foregut, and adaptations of hindgut fermenters
An oft-cited nutritional advantage of large body size is that larger animals have lower relative energy requirements and that, due to their increased gastrointestinal tract (GIT) capacity, they achieve longer ingesta passage rates, which allows them to use forage of lower quality. However, the fermentation of plant material cannot be optimized endlessly; there is a […]
Giraffe Helmholtz resonance
Introduction The following acoustical assessment documents infrasonic vocalizations that are produced by giraffe and demonstrates these vocalizations occur in social contexts. It also proposes that Helmholtz resonance is used to produce such vocalizations. Giraffes are large ruminant browsers that live in sub-Saharan Africa. Giraffe females and young are usually sighted in small groups whose composition […]