Migratory herds of wildebeests and zebras indirectly affect calf survival of giraffes
In long-distance migratory systems, local fluctuations in the predator–prey ratio can exhibit extreme variability within a single year depending upon the seasonal location of migratory species. Such systems offer an opportunity to empirically investigate cyclic population density effects on short-term food web interactions by taking advantage of the large seasonal shifts in migratory prey biomass. […]
Antipredator behaviour of African ungulates around human settlements
As human populations grow and come into more frequent contact with wildlife, it is important to understand how anthropogenic disturbance alters wildlife behaviour. Using fine-scale spatial analyses, we examined how proximity to human settlements affects antipredator responses of ungulates. We studied seven common ungulate species (Kirk’s dik-dik, Thomson’s gazelle, impala, common warthog, common wildebeest, common […]
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 […]
DNA metabarcoding illuminates dietary niche partitioning by African large herbivores
Niche partitioning facilitates species coexistence in a world of limited resources, thereby enriching biodiversity. For decades, biologists have sought to understand how diverse assemblages of large mammalian herbivores (LMH) partition food resources. Several complementary mechanisms have been identified, including differential consumption of grasses versus nongrasses and spatiotemporal stratification in use of different parts of the […]
Dynamics of ungulates in relation to climatic and land use changes in an insularized African savanna ecosystem
Land use change and human population growth are accelerating the fragmentation and insularization of wildlife habitats worldwide. The conservation and management of wildlife in the resultant ‘island’ ecosystems in the context of global warming is challenging due to the isolation and reduced size of the ecosystems and hence the scale over which ecosystem processes can […]
Seasonal ungulate distribution and densities on Manyara ranch 2012-13
The northern Tarangire-Manyara Ecosystem in Tanzania is among the richest areas in the world for large mammal diversity and abundance, and Manyara Ranch provides crucial wildlife habitat for migratory and resident species between the Tarangire River and Lake Natron. This area is essential to the survival of migratory wildlife populations in the area, and sustains […]
Delayed effects of fire on habitat use by large herbivores in Acacia drepanolobium savanna
Fire is frequently used as a wildlife management tool in savanna habitats (Trollope, 1982). Burning stimulates sprouting of plants (Vesey-Fitzgerald, 1971), improving forage quality (Komarek, 1967; Dorgeloh, 1999). Several studies have supported quantitatively what has been well known by managers for some time, namely that ungulates are attracted by resprouting vegetation in recently burned areas […]
The structure of the masseter muscle in the giraffe (Giraffa camelopardalis)
In the giraffe (Giraffa camelopardalis), the masseter muscle was divided into several layers. The superficial and more medial (second) tendinous sheets of the masseter muscle fused with each other at the dorso-caudal part and a fleshy portion was located between these tendinous sheets. In the rostral part, the most superficial tendinous sheet turned around as […]
Comparative changes in adult vs. juvenile survival affecting population trends of African ungulates
Among large mammalian herbivores, juvenile survival tends to vary widely and may thus have a greater influence on population dynamics than the relatively constant survival rates typical of adults. However, previous studies yielding stage-specific survival rates have been mostly on temperate zone ungulates and in environments lacking large predators. Annual censuses coupled with assessments of […]
Social influences on vigilance behaviour in giraffes, Giraffa camelopardalis
Vigilance in ungulates is considered to have a predominantly antipredator function, with the frequency and duration of scans per individual decreasing with increasing group size. Social influences on vigilance scans have been overlooked in studies on ungulates, although studies in primates and birds show that conspecific scans are important determinants of vigilance behaviour. We investigated […]