Ph. D, Faculty of Science, University of Witwatersrand, 2011 / The aim of biological management for black rhinoceros (Diceros bicornis) conservation is to maximise meta-population growth rates to aid species recovery. This research investigated how adaptive resource use in response to seasonal variation in resource availability could affect maximum productive habitat capacity for this critically endangered species. Analysis was based on a population of rhinos which had shown excellent annual growth rates and low inter-calving intervals since re-introduction to Tswalu Kalahari Reserve in the Northern Cape of South Africa in 1995. Acacia haematoxylon, a semi-evergreen species, was identified as the key resource forming the majority of diet contents during the late dry season. Use of this species resulted in a low level of seasonal variation in dietary contents of energy and protein. During the data collection period, energy and protein gains of individual female rhinos were estimated to exceed maximum requirements for reproduction throughout the seasonal cycle. An experiment designed to test the compensatory growth response of A. haematoxylon found that clipping trees in a way that simulated rhino browsing stimulated an increased growth response in the following wet season. This response indicated potential for a facilitatory relationship in the short term. A large proportion of the available area at Tswalu was not used by black rhinos. Home range location and habitat type selection within home ranges during the dry season were positively associated with two shrubveld habitat types containing greater A. haematoxylon biomass than other habitat types. Results from all aspects of field data analysis emphasized the importance of A. haematoxylon as the key dry season resource for black rhino at Tswalu. Field data were used to develop a conceptual model of how seasonally adaptive resource use by black rhinos could determine maximum productive habitat capacity. The crux of the model was to estimate the highest population density at which female rhinos could attain maximum energetic gains for reproduction throughout the entire seasonal cycle. The most limiting period was the nutritional bottleneck during the late dry season. The rationale behind this approach was to enable females to maintain body condition and be capable of meeting nutritional requirements for reproduction throughout the year, thus minimizing inter-calving intervals and maximising population growth rates. Model projections indicated that female rhinos could not attain energy gains for reproduction throughout the dry season in certain habitat types due to low availability of A. haematoxylon. However, model outputs indicated potential for an increase in rhino density by approximately one third in the two favoured shrubveld habitat types, assuming that habitat conditions remained unchanged. Availability of semi-evergreen A. haematoxylon was identified as the key vegetation component determining maximum productive habitat capacity for black rhino at Tswalu. Monitoring available biomass of this species at the end of the dry season could provide a simple plant-based indicator of how close the population is to maximum productive habitat capacity. Managing rhino densities in fenced reserves elsewhere around spatial and temporal availability of key resources may assist in achieving black rhino conservation goals of maximising metapopulation growth rates. Joanne Aileen Shaw

MSc., Faculty of Science, University of the Witwatersrand, 2011 / Black rhinos are being moved to small protected areas in an attempt to expand their range; and factors commonly found within these small protected areas could influence black rhino ecology. From the literature we understand how biological factors affect rhino resource selection but not in the context of small reserves. This study investigates the home range establishment of black rhinos and those factors commonly associated with small reserves that affect rhino habitat-use as well as weigh the relative importance of each of them. The factors considered were human disturbances such as residences, lodges, roads and fences, slope, elevation, perennial water, burnt areas and vegetation type. Minimum convex polygon, 50% core and 95% local convex hull (LoCoH) was used to generate home ranges from sightings data collected for 17 individuals. The mean 95% LoCoH home range was 3.77 km² (95% CI: 2.92- 4.63, n=17), and is comparatively small in relation to the adaptive kernel home ranges of previous studies. A use-availability resource selection function showed that black rhinos avoided areas close to residences, lodges, camps, and perennial water, and these variables played a bigger role than their selection for thicket vegetation. These factors have a highly significant effect on rhino resource selection, and this effect is magnified due to the density of human disturbances and water points commonly found in small reserves. It is essential that this knowledge be applied in the management of reserves protecting black rhinos.

Massive declines in the latter half of the 20th century left black rhinoceros populations perilously close to extinction with only approximately 3600 individuals remaining, in contrast to estimated census numbers of over 100,000 individuals in 1900. While Diceros bicornis bicornis is the second most abundant subspecies of black rhino, behind D. b. minor, relatively few genetic studies have focused on this taxon. I used polymorphic DNA microsatellite markers to describe population structure in this subspecies. Using these genetic markers, the goals of this study were: i) to characterize the genetic variability of D.b. bicornis individuals (n = 170) found in Etosha National Park, Namibia, using seven DNA microsatellite markers, ii) to determine if there is population structure within Etosha National Park, using both traditional Wright’s F-statistics and a Bayesian model that requires no a priori population assignment, iii) to determine relatedness amongst founding and newly introduced black rhinoceroses held in private game farms throughout Namibia, using moment estimators of relatedness; and iv) to determine parentage of game farm rhinos with partial or no pedigree data available, using likelihood-based methods. I found that: i) the levels of genetic diversity in D.b. bicornis from Etosha National Park are consistent with previously published studies using microsatellite markers, and are relatively high; ii) the population structure within Etosha National Park is ambiguous using traditional F-statistics, but can be subdivided into three diagnosable clusters (western, central and eastern) using a Bayesian approach; iii) a relatively high degree of relatedness exists among founding members of game farm rhinos; and iv) assignments of parentage had greater success when there were fewer candidate parents and support the notion that black rhinoceroses are polygynous. / Thesis (Master, Biology) -- Queen's University, 2009-06-01 10:18:14.064

Biodiversity changes, often resulting from climate change, land transformation, and the transportation of organisms across geographical barriers are among the most important human induced global changes. To optimize the spatial allocation of conservation efforts, and how to best protect indigenous species, requires an understanding of the principal determinants that structure ecological communities and ecosystems. We studied community-level interaction among a diverse assemblage of specialist and generalist browsers in an African savanna. Hluhluwe-iMfolozi Park (HiP), South Africa, hosts a complete assemblage of vertebrate species across all trophic levels and contains a diverse guild of large browsers. Using species abundance distributions (SADs) we graphically illustrate the diversity and abundance of woody species that comprise six structural habitat types within HiP. We calculated the Shannon-Wiener index and Pianka’s niche overlap to characterise the utilization of forage across habitat types among different browser groups. By using individual plant traits we investigated mechanisms of resource partitioning. We specifically investigated the effect of the temporal expansion of an exotic invasive plant (Chromolaena odorata) on the critically endangered black rhino using GIS and statistical analyses. We found that lower lying habitat types were important forage resources for browser species and individual plant traits that are highly correlated with digestibility strongly predicted browser preference. Black rhino used different strategic and metabolic mechanisms to successfully compete within the same forage height range of other, smaller, browsers. C. odorata has negatively impacted forage species utilization and has led to a spatial reorganization of the population of black rhino. This may partly explain the recent decline in the population. The principles within metapopulation management can be used to successfully conserve endangered species. High diversity of browse across three dimensions (diversity, abundance and maximum height) relative to area facilitates a high diversity and abundance of different browsing herbivores. Therefore the spatial configurations of resources ranging from topological attributes to the individual plant traits are essential to maintaining viable populations of many co-occurring species within conservation areas of limited extent. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2009.

Thesis (Ph. D.)--Ohio State University, 2004. / Document formatted into pages; contains xiii, 126 p. Includes bibliographical references. Abstract available online via OhioLINK's ETD Center; full text release delayed at author's request until 2007 Sept. 21.

Thesis (MSc. (Vet. Trop. Diseases))--University of Pretoria, 2003. / Includes bibliographical references.

This study aims to develop a predictive understanding of the resource use, impacts and interactions of elephant Loxodonta africana and black rhinoceros Diceros bicornis in the succulent thickets of the Eastern Cape, South Africa. While these megaherbivores typically dominate the biomass, elephant are more abundant, such that their impacts off-set that of all other herbivores. Consequently, this thesis has three main foci: first, developing a mechanistic understanding of the influences of elephant; second, developing predictive insights into elephant impacts on plant communities; finally, an understanding of the knockon-effects of the impacts for coexisting rhinoceros. Thus, by documenting the diet and dietary preferences of elephant, I firstly show that only about 18 percent of the species previously thought vulnerable to herbivory, occur in the diet. This refutes the generally held belief that elephant herbivory is the primary driver of decline among plants, and emphasizes the likely contribution of other mechanisms (e.g. trampling, knock-on-effects, etc.). Thus, the accurate prediction of the impacts caused by elephant requires an understanding of previously marginalized mechanisms. From here, I quantify >50 years of impacts on the thicket shrub community and test their spatial and temporal extent near water. I confirm the vulnerability of thicket to transformation (particularly near water) as the accumulated influences of elephant reduce community composition and structure, and predict that these impacts will eventually bring about landscape-level degradation and a significant loss of biodiversity. Importantly, results show an uneven distribution of effects between elements of this community: from community composition and structure, to the structure of individual canopy species and ecological functioning. While these findings confound our interpretation of the extent of the impacts, it demonstrates the importance of explicitly recognizing biodiversity and heterogeneity for the conservation management of elephant. Finally, I test the consequences of the impacts for coexisting rhinoceros. While I show that this causes rhinoceros to change their foraging strategies in the presence of elephant at high densities, I also show that elephant may facilitate access to food for rhinoceros at reduced densities. These findings indicate the importance of elephant in driving the structure and composition of the thicket shrub community and the consequences of this for coexisting large herbivores. Thus, developing a predictive understanding of the spatial and temporal variations of elephant impacts between elements of biodiversity and the mechanisms driving these changes are key to their management. This implies that the effective conservation management of elephant can only be achieved through the careful, scientific design of monitoring programmes.

Thesis (MSc (Veterinary Tropical Diseases)--University of Pretoria, 2009. / Includes bibliographical references. Also available in print format.

Many aspects of habitat selection have been largely ignored in conservation planning of large mammals, including variation between day and night movement patterns, inter-individual niche variation of conspecifics and translocated individual‟s responses to new environments in relation to the influence of ecogeographical variables. Being a solitary moving animal with a known tendency to move through the night, the black rhino Diceros bicornis is a perfect species to test theories about individual spatial and temporal variation in habitat utilisation. I tested the appropriateness of using carrying capacity (CC) estimates as a tool for population conservation planning, and as an indicator of habitat utilisation for black rhino. I found individual selection was not related to the value of the habitat according to modelled CC. I therefore do not recommend the use of a priori calculations of resource quality and abundance of habitats (CC estimates), which do not take into account the factors that influence an animal‟s selection of a habitat, as indicators of species habitat use. Secondly I tested whether current methods of analyzing mainly diurnal location data of animals result in accurate ecological or conservation conclusions. I found a circadian variation in habitat use for different behaviours, and that excluding nocturnal data from home and browsing range analyses would provide inaccurate results for black rhino habitat use. I then tested for inter-individual niche variation amongst two populations of black rhino at various scales of selection, ranging from habitat through to browse selection. I showed that black rhino, a selective browser, had a significant degree of inter-individual habitat and dietary niche variation. Consequently, pooling habitat location data and diet selection data for black rhino individuals in a population does not reflect the actual selection of any, or many, individuals. To clarify which ecogeographical variables might influence this selection I ran maximum entropy models on individual‟s diurnal locations across the landscape. I was then able to develop a habitat suitability model which was based on the individual rather than population, providing a more accurate prediction. I repeated the individual models in phases, from the initial post-release phase after the release of individuals onto a new reserve through to their „settled‟ phase, allowing me to explore the effect of habitat variables on different settling phases of translocated animals. The results indicate that all the rhinos‟ acclimation phase lasted no longer than 25 days and that to minimize disturbance to the settling process all individuals in a newly released cohort should be released within this period. This study as a whole provides conservation managers with a better ecological understanding of black rhino in conjunction with a number of management tools. This will enable conservation managers to better understand the way animals utilise and perceive their environment, allowing for better monitoring and analyses of animal movements. This will aid in the development of strategic management plans in the conservation of not only animal species but also the ecosystems that they reside in and the identification of suitable areas for future conservation of animal species. / Thesis (Ph.D.)-University of KwaZulu-Natal, Westville, 2010.

Between November 2002 and October 2006, blood samples were collected from 46 black rhinoceroses (Diceros bicornis) originating from various national parks and game reserves within South Africa. The samples were divided into two groups, based on the black rhinoceros subspecies from which they originated: twenty-eight (n = 28) of the samples originated from subspecies D. b. bicornis, and eighteen (n = 18) from subspecies D. b. minor. DNA was extracted; the V4 hypervariable region of the 18S rRNA gene amplified and subjected to the Reverse Line Blot (RLB) hybridization assay. The RLB results demonstrated the presence of either Theileria bicornis or Babesia bicornis in 9 of the 46 samples examined. A further three PCR products failed to hybridize with any of the Babesia or Theileria species-specific probes, and only hybridized with the Babesia/Theileria genus-specific probe, suggesting the presence of a novel species or variant of a species. Samples collected from black rhinoceroses originating from the more arid areas of South Africa, Tswalu Game Reserve and the old Vaalbos National Park, were found to be apparently free of T. bicornis and B. bicornis piroplasms. Based on these findings, it was concluded that B. bicornis and T. bicornis are relatively widespread in black rhinoceros populations in South Africa and pose a potential risk to the success of metapopulation management programs. Of the two black rhinoceros subspecies that occur in South Africa, D. b. bicornis is at greater risk due to their apparently Babesia/Theileria-naïve status in certain areas, when compared to the subspecies D. b. minor. Conservation managers need to carefully evaluate methods and procedures during the translocation of black rhinoceroses, especially when relocating from geographically and climatically diverse ecosystems and more so when dealing with the subspecies D. b. bicornis. Copyright / Dissertation (MSc (Veterinary Tropical Diseases))--University of Pretoria, 2009. / Veterinary Tropical Diseases / unrestricted