The reproductive performance, demography and spatial ecology of an extralimital white rhinoceros population
- Authors: Truter, Anja
- Date: 2021-04
- Subjects: White rhinoceros -- South Africa -- Eastern Cape , White rhinoceros -- Effect of poaching on -- South Africa -- Eastern Cape , White rhinoceros -- South Africa -- Eastern Cape -- Reproduction , White rhinoceros -- Dispersal -- South Africa -- Eastern Cape , White rhinoceros -- Food -- South Africa -- Eastern Cape , White rhinoceros -- Behavior -- South Africa -- Eastern Cape , Spatial ecology -- South Africa -- Eastern Cape , Animal populations -- South Africa -- Eastern Cape , Endangered species -- South Africa -- Eastern Cape , Spatial behavior in animals -- South Africa -- Eastern Cape , Shamwari Game Reserve (South Africa)
- Language: English
- Type: thesis , text , Master , MSc
- Identifier: http://hdl.handle.net/10962/177975 , vital:42895
- Description: The white rhinoceros (Ceratotherium simum) (hereafter rhino) is under threat of becoming extinct due to continued poaching for its horns. In South Africa and elsewhere in Africa private landowners have, over the last few decades, contributed to the conservation of various species, including rhinos, even in areas where they have not occurred historically (i.e., where they are extralimital). Unfortunately, very few studies have investigated the conservation contribution of extralimital white rhinos on private reserves to the overall meta-population and/or their reproductive performance. The first aim of my study was therefore to determine whether or not the white rhinos introduced to a private game reserve in the Eastern Cape Province in 1992 have been successful from a reproductive perspective. I calculated inter-calving intervals, age at first calving, conception period, sex ratio, fecundity and fertility rates for white rhinos over this 28-year period. The average annual population growth rate for the rhinos was 10%, which is higher than the recommended 5% by the Rhino Management Group. Trends in density-dependent parameters such as age at first calving and inter-calving intervals also indicated that my study population is still well below carrying capacity for white rhinos and is contributing positively to white rhino conservation in South Africa. The second aim of my study was to investigate home range size and vegetation preferences of white rhinos. Home ranges were mostly larger for all age groups compared to rhinos in their native range. Previously cultivated lands (dominated by several grass species) were preferred by all rhino age groups. The rehabilitation of these previous agricultural-based pastures has likely contributed to the successful introduction of the white rhino as an extralimital megaherbivore in the Eastern Cape. I conclude that although extralimital white rhino populations in the Eastern Cape can be successful from a reproductive perspective, their potential impact on the indigenous biodiversity of the region should be a key future research priority. , Thesis (MSc) -- Faculty of Science, Zoology and Entomology, 2021
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- Date Issued: 2021-04
Options for eland: a multi-scale assessment of antipredatory responses of a vulnerable prey species to their dominant predator in the Eastern Cape, South Africa
- Authors: Leaver, Jessica
- Date: 2014
- Subjects: Endangered species -- South Africa -- Eastern Cape , Predatory animals -- Control -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/6570 , vital:21113
- Description: Eland Tragelaphus oryx are the largest and slowest African antelope, falling within the preferred weight range of the prey of lions Panthera leo. Little is known, however, about the antipredatory strategies employed by eland. Rapid population declines in several small reserves following the reintroduction of lions suggest that the antipredatory strategies of eland may be compromised in spatially limited areas. This emphasises the need for research aimed at investigating how eland respond to lions, particularly in the spatial context, given that lions are increasingly being reintroduced into small reserves in South Africa. This study aimed to investigate lion-eland interactions at multiple scales and determine where on the landscape eland were vulnerable to predation. Adult female eland (n = 3 per site) in breeding herds were collared with GPS satellite collars in two study sites; the Nyathi section of Addo Elephant National Park (Nyathi) and Mountain Zebra National Park (MZNP) in the Eastern Cape, South Africa. A reintroduced population of lions, comprising two males and one female, was present in each study site, with individuals fitted with GPS satellite collars. At a broad spatiotemporal scale, eland did not avoid lions and there was considerable overlap between eland and lion home ranges in both study sites. At a finer spatiotemporal scale however, eland and lion space use was asynchronous in time, except in the case of the female lion in Nyathi where there was considerable overlap at the finest temporal scale investigated (i.e. monthly). Herd-associated eland in Nyathi were killed most frequently in areas associated with high long-term use by the female lion, showing that failure to avoid the female lion at a fine scale increased predation risk for eland. Secondly, eland in Nyathi were killed most frequently in habitat types of intermediate structural density (i.e. mixed habitats), which limited the viewshed of eland but presumably offered increased forage. This habitat type was selected for by eland, despite it being associated with a higher level of predation risk. This suggested that eland in Nyathi traded off safety for forage. In MZNP, predation of herd-associated eland was low which reflected the limited spatial overlap between eland and lion at a fine scale in this reserve. In Nyathi, but not in MZNP, eland responded to lions within 1.5 km by increasing their movement rate, with this response particularly strong at night. The findings of this study show that eland responses to lions are scale-dependent and site-specific. Furthermore, eland responses to lions were shown to be lion gender-specific. This study has increased our understanding of the antipredatory behaviours of eland and demonstrated the importance of investigating prey responses to predation risk at multiple scales.
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- Date Issued: 2014
Life history, population dynamics and conservation status of Oldenburgia grandis (Asteraceae), an endemic of the Eastern Cape of South Africa
- Authors: Swart, Carin
- Date: 2008
- Subjects: Compositae , Fynbos ecology -- South Africa -- Eastern Cape , Endemic plants -- South Africa -- Eastern Cape , Rare plants -- South Africa -- Eastern Cape , Plant populations -- South Africa -- Eastern Cape , Vegetation dynamics -- South Africa -- Eastern Cape , Plant conservation -- South Africa -- Eastern Cape , Endangered species -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4230 , http://hdl.handle.net/10962/d1003799 , Compositae , Fynbos ecology -- South Africa -- Eastern Cape , Endemic plants -- South Africa -- Eastern Cape , Rare plants -- South Africa -- Eastern Cape , Plant populations -- South Africa -- Eastern Cape , Vegetation dynamics -- South Africa -- Eastern Cape , Plant conservation -- South Africa -- Eastern Cape , Endangered species -- South Africa -- Eastern Cape
- Description: Oldenburgia grandis is a rare, long-lived woody paleoendemic of the Fynbos Biome of South Africa. Confined to quartzite outcrops, it has a small geographic range and narrow habitat specificity. O. grandis responds to its fire-prone environment by resprouting. Elasticity analysis of O. grandis reveals that growth and fecundity were traded off for persistence of adult, mature and sapling stages. Morphological adaptations such as a corky fire-resistant bark and the ability to resprout after fire are traits that O. grandis have evolved to persist in a frequently disturbed environment. Population growth rate for sites undisturbed by fire for a number of years (l = 1.01) and sites at various stages of recovery after fire (l = 1.00) were very similar. The highest variation in transition probabilities for all sites was seen in the persistence of the seedling stage and growth from seedling to sapling. Observed population structure and stable stage distribution determined by the matrix model show that sites recently undisturbed by fire had high abundances of the adult and sapling stages. A peak in sapling stages was seen for the stable stage distribution where similar peak in sapling numbers were seen for population structures of sites at various stages of recoveryafter fire. Favourable environmental conditions for the persistence of O. grandis populations include no fire with transition probabilities between the observed minimum and maximum and fire frequency at a 10 year interval where seedling protection from the fire is high and adult and mature mortalities during the fire are low. Stochastic environmental events that could put populations (particularly small populations) at an increased risk of extinction include high to moderate fire intensities where seedling protection from the fire is low and adult and mature mortalities are high as a result of the fire.
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- Date Issued: 2008