Search the Article Database:

Search our library of articles, papers and other published materials. You can use keywords or boolean-style search:

Body size and habitat as determinants of tick infestations of wild ungulates in South Africa

The purpose of the present work was to test the hypothesis that the intensity of tick infestation on South African wild ungulates is proportional to surface area of the host (body weight 0.67} and to assess the role of habitat preference on the intensity of infestations. The results support previous suggestions that larger ungulates are more important hosts for adult ticks, however, the intensity of infestation of nymphs and larvae is proportional to the surface area of the host. Grazers

View Details + Download

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 population model. Based on this model two auxiliary models, called the floor and ceiling models, are derived. These models predict the upper and lower threshold

View Details + Download

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 Africa. Census records for 11 ungulate species in South Africa’s Kruger National Park over 1977–96 reveal severe population declines by seven species, which were inadequately

View Details + Download

Effects of body size on the diurnal activity budgets of African browsing ruminants

We compared the diurnal activity budgets of four syntopic species of African browsing ruminant that differ widely in body size. These were concurrently studied through all phases of the seasonal cycle, in the same area, using the same methods. We tested five predictions from the literature on how body size is expected to influence the behaviour of tropical ungulates: the smallest members of the browsing ruminant guild exhibit (1) the lowest allocation of diurnal time to activity; (2) the greatest

View Details + Download

Evaluating Population Persistence of Censused and Unmanaged Herbivore Populations from the Kruger National Park, South Africa

The application of the Dennis et al. (Ecol. Monogr., 61, 1991) model to data from 12 herbivore populations from the Kruger National Park, South Africa, introduces “risk assessment’ procedures into the conservation management of free-ranging species. The model enables one to predict the probability of reaching an arbitrarily defined threshold population size using census figures from censused and unmanaged populations. It also provides an objective evaluation of population persistence based on past performance. Of the 12 species investigated, five (impala

View Details + Download

Giraffes and the pollination ecology of knobthorns (Acacia nigrescens)

Giraffes (Giraffa camelopardalis) consume large quantities of knobthorn (Acacia nigrescens) flowers every year, and may be acting as pollinators. Because knobthorns flower in the late dry season, nutritionally a critical time of year for ungulates, the flowers are an important source of food for giraffes, especially since they are not physically protected against herbivory. Giraffes visit the flowering trees reliably year after year, carry pollen on their heads and necks, and cover large distances between knobthorns. In this study, conducted

View Details + Download

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 population structure enabled annual survival rates to be estimated for the juvenile, yearling and adult segments of nine ungulate species in South Africa’s Kruger National

View Details + Download

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 group size effects in giraffes and examined social influences on their scanning behaviour, as well as the influence of feeding posture. We found that group

View Details + Download

Oscillations in large mammal populations: are they related to predation or rainfall?

Cyclic population dynamics is relatively common among populations of small mammals in high latitudes but is not yet established among African savanna ungulates. However, oscillations may be expected in large mammal populations subject to quasi-periodic oscillations in regional rainfall. We evaluated evidence for environmentally entrained oscillations in a large-mammal predator–prey system in Kruger National Park (KNP), South Africa, where rainfall exhibits quasi-periodic oscillations. The evaluation is based on analysis of comparative changes in the abundance of twelve ungulate species throughout

View Details + Download
© All articles are copyrighted to the original authors/publishers unless otherwise stated. Any PDF files provided by the GRC are for personal use only and may not be reproduced. The files reflect the holdings of the GRC library and only contain pages relevant to giraffe study, and may not be complete. Users are obliged to follow all copyright restrictions.

Privacy Policy Cookie Policy