Natural & Applied Sciences

Natural & Applied Sciences Research Papers/Topics

An analysis of numerical trends in African elephant populations

Abstract: The elephant debate deals largely with population size, how elephant numbers change over time, how they may affect vegetation, and how their populations should be managed. Trends in elephant numbers frequently motivate management decisions, and past efforts to alleviate elephant impact aimed at controlling population size. However, methodological and statistical constraints may influence interpretation of trends and lead to incorrect management decisions. Furthermore, inferences ab...

Indirect interactions between elephants (Loxodonta africana) and mopane caterpillars (Imbrasia belina) through their shared food resource – mopane trees (Colophospermum mopane)

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...

Genetic diversity and hybridisation estimates of Arctocephalus tropicalis and A. gazella from Marion Island

Abstract: In this study, hypervariable region I (HVRI) of the mitochondrial DNA (mtDNA) control region, and five microsatellite loci were used to assess genetic variability and the extent of hybridization between the two fur seals (Arctocephalus tropicalis and A. gazella), that occur on Sub-Antarctic Marion Island. Both species were harvested during the 18th and 19th centuries, leading to a reduction in population size and the extinction of A. gazella at some localities. Whilst both species ...

Life history studies of the southern elephant seal population at Marion Island

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...

Feeding ecology and social organisation of honey badgers (Mellivora capensis) in the southern Kalahari

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 ...

The seasonal haulout cycle of the declining southern elephant seal, Mirounga Leonina, population at Marion Island

Abstract: Data recorded from annual tagging and regular tag resightings of southern elephant seals at Marion Island, permitted the investigation of temporal variation in the terrestrial haulout cycle of this species, and estimation of participation levels in the little understood resting haulout phase, that could be related to age, sex, and sexual status. Primigravid females moulted later, and were less inclined to rest, than nulligravid females of the same age, but moulted earlier than matu...

Social behaviour of the Eland (Tayrotragus Oryx) on Loskop Dam Nature Reserve

Abstract: Please read the abstract on page 3. Copyright 1975, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Underwood, R 1975, Social behaviour of the Eland (Tayrotragus Oryx) on Loskop Dam Nature Reserve, MSc dissertation, University of Pretoria, Pretoria, ...

Patterns in the distribution and abundance of terrestrial arthropods on sub-Antartic Marion Island

Abstract: Quantitative studies of complete soil arthropod communities are considered essential if a thorough understanding of the structure and dynamics of soil faunas, and their likely response to anthropogenic environmental change, is to be gained. In practice, however, high species richness and poor taxonomic knowledge for most systems often hampers the acquisition of such information. In consequence, many studies resort to the use of higher taxa or more qualitative data. Sub-Antarctic te...

Arthropod assemblages in a savanna invaded by Opuntia stricta (Cactaceae) in the Kruger National Park, South Africa

Abstract: Invasive alien species are considered the second greatest threat to global biodiversity after habitat loss. South Africa is not immune from such threats and it is estimated that 10 million ha (8.28%) of land has been invaded to some extent by invasive alien species. Although South Africa has been invaded by several taxa, it is the effect of invasive trees and shrubs that has been environmentally and economically most damaging. The concerns raised due to the effects of biological in...

Resource competition between spotted hyaenas, Crocuta crocuta, (Erxleben 1777), and brown hyaenas, Parahyaena brunnea, (Thunberg 1820)

Abstract: Field data were collected and analysed on the feeding and spatial ecology of spotted hyaenas and brown hyaenas living in the Madikwe Game Reserve. Methods used to estimate the population of spotted and brown hyaenas include audio call-in surveys, photographic records and mark-resighting. The localized convex hull method was used on data collected from latrine surveys, radio-telemetry, sighting records, and camera-trapping to determine the spatial ecology of hyaenas in Madikwe. Faec...


646 - 660 Of 8876 Results