Abstract: The seasonality of wild caught Cape mole-rats was investigated, focusing on endocrine, neuroendocrine and neuroanatomical parameters. The Cape mole-rat reproduces only during the winter rainfall period of the western Cape Province. Interestingly, the gonadal steroid hormones do not show any significant seasonal patterns in either males or females. In addition, the pituitary does not exhibit a reduced sensitivity to GnRH stimulation during the non-breeding season in either sex. More...
Abstract: Mopane (Colophospermum mopane) trees are browsed upon by two key species, namely mopane caterpillars (Imbrasia belina) and African elephants (Loxodonta africana), which each inflict a different type of damage while feeding, namely defoliation (leaf removal) and pruning (branch and/or stem breakage). Damage type can have a significant influence on plant responses, and these induced changes in morphological and chemical characteristics of regrowth can influence the subsequent feeding...
Abstract: Please read the abstract in the section oofront of this document
Abstract: Please read the abstract in the section 00front of this document.
Abstract: Holistic studies of mammalian life history factors and their consequences on population demography require an intensive, multifaceted field methodology and effort over long temporal scales. A 25-year longitudinal mark-recapture experiment on southern elephant seals, Mirounga leonina, at Subantarctic Marion Island provide such a foundation for demographic analyses and relevant methodology advancement. Two gaps in the methodology related to life history and population demographic res...
Abstract: The lack of fundamental biological information on the honey badger Mellivora capensis and its vulnerable conservation status were the motivating factors behind this study. A study population of 25 individuals (12 females; 12 males) was radio-marked in the Kgalagadi Transfrontier Park (KTP), South Africa. Through a combination of radio telemetry and visual observations (5 244 h) of nine habituated individuals (five females; four males), the feeding ecology, scent marking and social ...
Abstract: Pup mortality of southern elephant seals at Marion Island from 1990 through 1999 ranged from 1.6 to 7.3%, averaging 3.8%. Pup mortality was density independent and dismissed as being a major population regulating agent at Marion Island. Juvenile survival over two periods, one during the population decline and the other after the population had stabilised, was assessed and compared using mark-recapture models. Survival was age- but not sex-related and on average, the probability of ...
Abstract: The present study investigates trap success, species richness, community structure, capture-recapture ratios, sex, population estimates, climatic effects, diversity, age structure, signs of reproduction, and seasonal changes in the body biomass in seven broad vegetation communities in the Bankenveld Grasslands of Telperion in Mpumalanga Province, and Ezemvelo Nature Reserve in Gauteng Province, South Africa. This study focuses on the effect of past management influences on diversit...
Abstract: Habitat loss and fragmentation drives the current extinction crisis. The processes through which it affects biodiversity, however, are complex and poorly understood. This is especially true for spatially complex regions that comprise a mosaic of land-use types, which often range from protected areas to dense human settlements. In such human-modified landscapes, it is important to determine the extent and impact of changing land-use patterns on biodiversity if we are to meet conserv...
Abstract: Since the energy available to an animal for cell growth, thermoregulation, reproduction and other physiological functions is highly dependent on seasonal environmental changes many small mammals breed seasonally during times when environmental conditions are most favourable for growth and survival of the young. In the tropics and sub-tropics, seasonal rainfall appears to be the main reason for seasonal breeding. In order to maximize fitness, it is important for an animal to be able...
Description: Thesis (PhD)--University of Pretoria, 1992.
Abstract: This thesis investigates a number of aspects of the biology of the East African root rat, Tachyoryctes splendens (Rüppell, 1835) and provides important information currently depauperate in the literature. These aspects include the general burrow architecture with respect to fractal dimension (i.e. exploration efficiency), locomotory activity patterns in relation to specific light cycles, the pattern of reproduction, age structure and population growth characteristics based on cran...
Abstract: The study investigated the origin and diversity of the three matrilineally-defined invasive, commensal Rattus species, namely R. norvegicus, R. rattus and R. tanezumi known to occur in South Africa after routine identification of the species using molecular techniques. Subsequently, their role as potential zoonotic disease reservoirs in primarily urban environments with particular interest in their potential to transmit and spread zoonotic disease through direct contact as well as ...
Description: A thesis submitted to the Faculty of Science in fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Zoology, Kenyatta University.
Abstract: Dengue (DENV) and Yellow fever (YFV) viruses are medically important flaviviruses that are transmitted by Aedes mosquito vectors of the subgenus Stegomyia especially Aedes aegypti and Aedes bromeliae, respectively, in East Africa.Urbanization has been identified as a major driver in the emergence of these diseases because of the permissive environment it creates promoting the convergence of susceptible human hosts and local vectors. However, while dengue outbreaks have mainly been ...