The giraffe and its food resource in the Serengeti. II. Response of the giraffe population to changes in the food supply
The dynamics of the giraffe population of the Serengeti were quantified to ascertain the response of the population to the increasing biomass of the available browse resource. Aerial counts conducted in 1971 and 1976 together with analyses of fecundity and mortality data suggest a rate of population increase of some 5-6% per annum. Compared with […]
Population dynamics of the Maasai giraffe (Giraffa camelopardalis tippelskirchi) in Tarangire-Manyara Ecosystem
Demographic studies can show overall population performance, help understand population structure and recognize animal distribution and movement. In order to investigate the social structure of giraffes in the Tarangire-Manyara Ecosystem, data on population structure, sex ratios, age ratios and habitat preference were examined in three protected areas. These areas included Lake Manyara National Park, Manyara […]
Early detection of declining populations using floor and ceiling models
1. Within Caughley’s (1994) declining population paradigm for conservation, we develop a realistic method of detecting population changes using floor and ceiling population models. 2. A theoretical framework for detecting declining populations is presented and applied to four ungulate species from Kruger National Park, South Africa. 3. Census data are fitted to a non-linear autoregressive […]
Large-scale ruminant genome sequencing provides insights into their evolution and distinct traits
The ruminants are one of the most successful mammalian lineages, exhibiting morphological and habitat diversity and containing several key livestock species. To better understand their evolution, we generated and analyzed de novo assembled genomes of 44 ruminant species, representing all six Ruminantia families. We used these genomes to create a time-calibrated phylogeny to resolve topological […]
Ecology of the giraffe in Tsavo East National Park, Kenya
The decrease in woody vegetation in Tsavo National Park has probably had adverse effects on woodland-adapted herbivores, including the giraffe (Girafa camelopardalis). In an ecological study we attempted to assess this species’ density, habitat preference and utilization, and population dynamics, using mainly road strip counts and identification of individual animals. Population structure varied seasonally and […]
ENSO, rainfall and temperature influences on extreme population declines among African savanna ungulates
Climatic variation associated with the North Atlantic Oscillation (NAO) and El Nin˜o- Southern Oscillation (ENSO) has a widespread influence on the population dynamics of many organisms worldwide. While previous analyses have related the dynamics of northern ungulates to the NAO, there has been no comparable assessment for the species rich assemblages of tropical and subtropical […]
Season of birth affects juvenile survival of giraffe
Variation in timing of reproduction and subsequent juvenile survival often plays an important role in population dynamics of temperate and boreal ungulates. Tropical ungulates often give birth year round, but survival effects of birth season for tropical ungulate species are unknown. We used a population of giraffe in the Tarangire Ecosystem of northern Tanzania, East […]
Giraffe demography and population ecology
Population dynamics describe temporal change in population size and structure and the processes that contribute to that change. For conservation to succeed, it is critical that we are able to detect changes in population size and the demographic processes in the population, and also we must learn how to effect change in population size by […]
All the eggs in one basket: A countrywide assessment of current and historical giraffe population distribution in Uganda
To design effective conservation and management strategies at the national scale, it is important to consider population trends across space and time. Here we assessed the near threatened Rothschild’s giraffe (Giraffa camelopardalis rothschildi) in Uganda. We applied individual-based photographic surveys to generate abundance estimates for all extant populations, using either mark-recapture estimates or complete enumeration, […]
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. […]