The research deals with bootstrap interval estimation of wildlife population sizes from multiple surveys in the Hluhluwe-Umfolosi Park. The jackknife procedure was also used to provide the standard errors for the survey estimates. The main wildlife speciese studied in the research were the White and Black Rhino. The survey estimates for the wildlife species were obtained using line transect sampling and mark-recapture methods respectively. The bootstrap and jackknife procedures were applied separately to each of the datasets. Bootstrap estimates for each of the time point were obtained and the confidence intervals of the bootstrap estimates were constructed using percentile and standard methods. The coverage probability was assessed using the Monte Carlo simulations. Only the nonparametric bootstrap was applied in this research and the results were compared to the jackknife results. The lengths of the confidence intervals were used to assess the confidence intervals with a shorter confidence interval being more exact. The estimates used for both the bootstrap and jackknife methodology were based on a simple state space model. The discrete state space model used was proposed by Fatti et al (2002). State space models provide a natural framework for estimating and predicting animal population abundance given partial or inexact information. The model takes into account the (unknown) birth rate in the population and all known losses (mortalities and relocations) and gains (introductions) in the population between successive surveys as well as the errors in the survey estimates.

How so many species coexist while utilizing the same resources is both of ecological interest and important for the management of wildlife communities and parks. This thesis endeavours to understand how grazing herbivores co-exist, with special emphasis on understanding the mechanisms of competition and facilitation over temporal and spatial scales. I compared the dry season use of grasslands, grass species, grass height and grass greenness by white rhino and three other ungulate species, zebra, wildebeest, and impala. I was specifically interested in the extent to which white rhinos, with their capacity to graze both short and tall grass, either competed with or facilitated other grazers. In Chapter Two, I clarify the mechanisms of facilitation and competition in terms of temporal and spatial scales, and discuss why there is little evidence in the literature to support these mechanisms. I conclude that evidence for facilitation through stimulation of grass re-growth during the growing season appears stronger than that for increased resource access through removal of obstructing grass structures during the dormant season. Facilitation may benefit the nutritional gains obtained by certain species in the short term, but these benefits do not appear to be translated into the expected population consequences. In collaboration with co-author Norman Owen-Smith, we suggested this could be due to seasonal tradeoffs between facilitation and competition, as well as to restrictions on the spatial extent of trophic overlap. In Chapter 3 Norman Owen-Smith and I compared the grass height use in relation to body size. We expected that the grass height favoured would increase with the body size of the herbivore species, as suggested from past studies of resource partitioning among large mammalian herbivores. Instead we found that the largest of these species, white rhino, concentrated on the shortest grass, while the smallest species, impala, favoured grass heights intermediate between those grazed by wildebeest and zebra. Results suggest that the scaling of mouth width relative to body size, and hence metabolic demands, is the primary factor governing grass height selection, rather than body size alone. Hence grazing successions governed by body size differences may not be a typical feature of their ecology, contrary to past suggestions. Furthermore, there was considerable overlap in grass height grazed among these four species, indicating that niche separation by grass height is inadequate alone to explain their coexistence. More attention needs to be paid to other aspects such as the grass species selected and habitat structure favoured. Chapter Four compared the overlap in grassland use and grass species use, as well as grass height and grass greenness of swards utilized by the herbivores as the dry season advances. I show that all species prefer grazing lawns during times of abundance, and that zebra leave grazing lawns before other species, and wildebeest leave grazing lawns before white rhino and impala. This suggests zebra and wildebeest may be competitively excluded from grazing lawns through a reduction in grass height, by white rhino and impala, during the dry season. However, white rhino are also potentially the ‘supreme’ facilitator increasing the availability of nutritious grazing lawns, as well as increasing the quality of those lawns through grazing in the wet season. A better understanding of the trade-off between “habitat facilitation” and competitive exclusion by white rhino, allows us to better understand how grazing herbivores co-exist.

The main aim of this study was to classify and describe the plant communities in the home range of white rhinoceros in order to understand the animal seasonal foraging ecology. To provide a detailed habitat description, forty sample plots were stratified randomly. A TWINSPAN classification, refined by Braun-Blanquet procedures, was carried out on the Viewpoint section of the reserve. Ten plant communities, grouped into five major community types, were identified. The veld condition and ecological carrying capacity in these communities were measured, stating an abundance of food on long grass while the short grass equal the number of short grass feeders. A number of behavioural aspects such as activity data, home range utilization and dietary usage were examined. Statistical methods such as the Spearman rank-order correlation, Wilcoxon sign test and Student T-test were used on rhino data. The difference in usage of the home range during wet and dry seasons was insignificant. / Environmental Sciences / M.Sc. (Environmental Management)

The main aim of this study was to classify and describe the plant communities in the home range of white rhinoceros in order to understand the animal seasonal foraging ecology. To provide a detailed habitat description, forty sample plots were stratified randomly. A TWINSPAN classification, refined by Braun-Blanquet procedures, was carried out on the Viewpoint section of the reserve. Ten plant communities, grouped into five major community types, were identified. The veld condition and ecological carrying capacity in these communities were measured, stating an abundance of food on long grass while the short grass equal the number of short grass feeders. A number of behavioural aspects such as activity data, home range utilization and dietary usage were examined. Statistical methods such as the Spearman rank-order correlation, Wilcoxon sign test and Student T-test were used on rhino data. The difference in usage of the home range during wet and dry seasons was insignificant. / Environmental Sciences / M.Sc. (Environmental Management)