Populations of secondary tree-cavity nesting bird species are often limited by a shortage of natural nesting sites. For the Southern Ground Hornbill Bucorvus leadbeateri that typically nests in natural tree cavities, the shortage of nesting sites is one factor potentially limiting population growth. The species is listed as endangered in South Africa, and vulnerable throughout the rest of its range. Nest boxes can improve the conservation status of threatened birds that are limited by nest-site availability. However, nest boxes or other types of artificial nests are not always beneficial to the target species, and their value as a conservation tool needs to be tested for each species. Wooden nest boxes were installed for ground hornbills in a study area in north eastern South Africa with a paucity of natural nest sites. In this thesis, I assess productivity, timing of breeding, and dispersal in the Southern Ground Hornbill in a study area supplemented with nest boxes and discuss the implications for the conservation of this endangered species. Nest boxes are an effective conservation tool to improve productivity in areas lacking natural tree cavity nesting sites. Breeding success (calculated as the proportion of nesting attempts that fledged a chick) and predation levels were similar for groups using nest boxes and natural nests. Natural nests were more buffered against cooling night temperatures, but otherwise nest boxes provided nesting conditions that were no better than natural nests. Timing of breeding for nests in natural tree cavities and nest boxes were similar. However, groups with access to a nest box attempted breeding more often than groups with access to a natural nest only, resulting in an 15 % increase in the number of fledglings per group compared to an adjacent protected area with no artificial nests. The number of breeding groups in the study area increased by 460 % over 12 years. However, there is a limit to the density of breeding groups. Breeding success was highest when breeding density was one breeding group per 90-120 km², so nests should be spaced ~10 km apart. Given that the threats to ground hornbills include persecution and poisoning, increasing the reproductive rate by providing nest boxes should assist in slowing the decline by the increased recruitment of offspring into the population. Timing of breeding varied across years. The first eggs laid each year ranged from 9 September to 14 November, and median lay date was 03 November. Breeding attempts that were initiated early in the season were more likely to fledge a chick than those initiated later in the season. Timing of breeding was delayed during warmer springs, particularly under dry conditions. In savannas, hotter spring temperatures could limit food availability, for example, if higher temperatures cause the vegetation to dry out, resulting in a rapid decline in insect flush, especially in the phytophagous insect groups that form a large part of the ground hornbill diet. Factors to consider when constructing and placing nest boxes include thickness of the cavity walls, entrance height above ground and density of nest boxes placed in the landscape. Breeding attempts in natural nests and nest boxes with thicker nest walls and those positioned with higher entrances above the ground increased breeding success. Therefore, nests should be constructed with cavity walls at least 6 cm thick and placed so that the entrances are situated > 6 m above the ground. With 186 ringed chicks fledging from the study area after the installation of nest boxes, it was possible to observe their dispersal within the study area and farther away into the adjacent Kruger National Park. There was no evidence for sex-biased dispersal. Males and females dispersed at similar ages, and over similar distances, raising interesting questions about inbreeding avoidance mechanisms in this species. If females do not disperse beyond the range of related males, how do related individuals avoid pairing, and what forms of individual recognition exist?

Different histories for forests in Southern Africa have been hypothesized from vegetation biogeography and pollen analysis. However, the history of forests is still controversial. Phylogeography uses gene genealogies to infer history of distributions. Two forest endemic moss species were sampled: Leptodon smithii; and Neckera valentiniana. Two gene regions were used, trnLF (chloroplast genome) and ITS1 (nuclear genome). Neckera valentiniana showed no variation from the populations sampled. Results from Leptodon smithii based on the trn and ITS region suggest that forests once were widespread, but then became fragmented. Dispersal corridors still exist between Southern Cape populations and Western Cape populations.

Includes bibliographical references / This thesis focuses on the economics and institutional aspects of community wildlife conservation in the context of local communities living adjacent to the Gonarezhou NationalPark in Zimbabwe. A significant proportion of wildlife in Zimbabwe, and in Southern Africa in general, is managed as a common pool resource by communities under community-based natural resource management. Several challenges threaten conservation efforts at both local and higher levels, thus hindering its ability to bring about development that might improve the welfare of poor rural communities participating in wildlife conservation. The most pressing issues in the wildlife sector include: inability to extract resource rents from wildlife conservation that in turn affect household welfare in terms of total household income and reduction in poverty and inequality, lack of capacity by local communities to solve collective action problems or lack of incentives to self-organise, and lack of comparable successful outcomes in CBNRM communities such as the wildlife conservancy communities. Learning from other successful communities that use community-based' models, such as wildlife conservancies, might provide important insights for policy makers and development practitioners. These issues are explored in three substantial papers included in this thesis. The thesis consists of five chapters starting with an introduction, followed by three papers and finally conclusions and policy implications. The study makes use of purpose-collected primary data from local communities living adjacent to Gonarezhou National Park in Zimbabwe. The first paper investigates the effects of wildlife resources on community welfare. Specifically, the paper examines the contribution of environmental income to) total household income,) poverty reduction, and) reduction in income inequality. Furthermore, it investigates the impact of environmental income on households in different income categories, the role of wildlife in the portfolio of environmental income and the determinants of environmental income generated by different households. To achieve the objectives above, the paper makes use of income quintile analysis, the Foster-Greer-Thorbecke poverty measure, Gini coefficient analysis, Ginidecomposition analysis, ordered logit regression model and instrumental variables estimation using heteroscedasticity-based instruments. The results show that the relative contribution of environmental income towards total household income is more pronounced in poor households, while the relative contribution of agricultural income is noticeable in wealthier households. In particular, wealthier households consumed more wildlife products in total than relatively poor households. However, poorer households derive greater benefit from the consumption of wildlife resources than wealthier households. Excluding wildlife compromised the relative contribution of environmental income and, at the same time, increased the relative contribution of farm and wage income. Environmental income has more impact in terms of poverty and inequality reduction in the lower income quintiles than in the upper quintiles. Wildlife income alone accounted for about 5.5% reduction in the proportion of households living below the poverty line. Furthermore, wildlife income had an equalizing effect, bringing about a 5.4% reduction in measured inequality.

1. Two species of seed feeding bruchid, Algarobius prosopis and A. bottimeri, were introduced to South Africa in 1987 and 1990 respectively, to curb the spread of the invasive weed Prosopis. Failure of A. bottimeri to establish and reduced effectiveness of A. prosopis due to interference by livestock resulted in the release of a third species, Neltumius arizonensis in 1992. 2. Algarobius prosopis populations have remained high but N. arizonensis has not been as successful. 3. Populations ofboth bruchids showed similar emergence patterns through the sampling period hence there is no temporal partitioning of resources. 4. Percentage emergence of N. arizonensis was low at the start of the season but increased as the season progressed with higher proportions of N. arizonensis emerging from 'tree' pods than 'ground' pods. Regardless of the spatial partitioning of resources by the two bruchids, N. arizonensis emergence numbers are still far lower than those of A. prosopis (approximately 1:4 respectively). 5. Oviposition strategies of N. arizonensis results in high levels of egg parasitism by Uscana sp., Trichogrammatidae, that A. prosopis escapes by ovipositing in concealed places avoiding detection by parasitoids. 6. Egg parasitism is extremely high on N. arizonensis eggs (67%) and has resulted in failure by N. arizonensis to establish large populations and hence its effectiveness as a biocontrol agent is negligible.

The habitat of an animal is extremely important as it provides that animal with the necessary resources for fulfilling its life-history requirements (Brennan & Block, 1993; Beyer et al. 2010). A habitat is defined as a region in environmental space which comprises of multiple abiotic and biotic variables influencing an animal's location (Krausman, 1999; Beyer et al. 2010). Animals tend to utilise discrete areas within a habitat, constituting part of their home range. Home range analysis helps to delineate the area used by an animal habitually and areas of concentrated use (Samuel et al. 1985; Seaman & Powell, 1996; Moorcroft et al. 1999; Mitchell, 2007; Rodgers & Kie, 2011). Patterns of differential use of space within an animal's home range are the result of competing demands and trade-offs. In this study, a kernel technique was used to determine the home range of four satellitetracked groups of Southern Ground-Hornbills Bucorvus leadbeateri in the Associated Private Nature Reserves (APNR) in the South African lowveld. Satellite data were analysed in ArcGIS® 9.3 to quantify habitat selectivity by groups of ground-hornbills at different times of the year to determine a) favoured habitat types, and b) the resolution with which they perceive their environment. Each of the I groups showed variation in the utilisation and extent of their home ranges on a seasonal basis. Home range sizes contracted towards the nest during the summer breeding season (December to March) and expanded during the dry season (April to September). Within the home range of one of the groups the physical characteristics of habitat types (i.e. vegetation types) were sampled at 250 random co-ordinates in order to assess whether habitat preference at the meso-scale can be explained by the physical attributes of that vegetation type. By profiling and quantifying the vegetation of areas in the home range that are used by Southern Ground-Hornbills to differing degrees, this information could be used as a proxy to facilitate re-introduction efforts, by providing a tool to identify optimal landscape configurations.

Deep-sea organisms are increasingly subject to bycatch interactions worldwide. Recent studies have shown that discard mortality can lead to significant declines in deep sea fish stocks, and highlight the inherent vulnerability of deep sea organisms to overexploitation due to their shared suite of conservative life history characteristics. Estimating the post-release mortality (PRM) rates of these deep-sea organisms is a necessary step towards responsible fisheries management, particularly as PRM represents a substantial source of uncertainty when estimating total fishery mortality. The deep-sea giant isopod Bathynomus giganteus and its relatives are captured as bycatch in numerous fisheries, although knowledge is limited regarding their population trends or response to capture and release. In order to assess and predict PRM in B. giganteus, we used reflex action mortality predictors (RAMP) whereby the presence or absence of target reflexes was used to create a delayed mortality model, and considered factors affecting mortality. Mortality rates five days post-capture ranged from 50-100% and both RAMP scores and time at the surface were significant predictors of mortality, although our conclusions regarding the effect of surface time are limited. In-cage video documented little movement within the 24 h monitoring period following cage deployment, and it appeared that surviving individuals often fed within the holding period after cage deployment. Our results suggest that PRM in B. giganteus is common and that this unaccounted source of mortality should be quantified and investigated for other deep-sea crustaceans as well. Similarly, bycatch interactions with deep-sea elasmobranchs can lead to dramatic declines in abundance over short time scales. Sharks hooked in the deep sea could face a higher likelihood of severe physiological disturbance, at-vessel mortality, and PRM than their shallower counterparts. Unfortunately, robust PRM rates have not yet been estimated for deep-sea elasmobranchs and as such are not currently incorporated into total fishery mortality estimates or bycatch assessments, limiting the effectiveness of conservation or management initiatives. We empirically estimated PRM for two focal species of deep-sea shark, the Cuban dogfish Squalus cubensis and the gulper shark Centrophorus sp. using post-release cages deployed at-depth. We calculated 24 h PRM rates of 49.7% (± 8.5 SE) for S. cubensis and 83% (± 16 SE) for Centrophorus sp. and identified shark size (total length), blood lactate, blood pH, and vitality scores as predictors of PRM in Squalus cubensis. We also observed all PRM within 11 h post-capture and demonstrated the effects of capture and recovery depth on stress and behavior. Our results suggest that PRM rates of deep-sea sharks are higher than previously assumed, and highlight the need for filling in this gap in fishery mortality estimates for other common deep-sea discards in the future. / A Thesis submitted to the Department of Biological Science in partial fulfillment of the Master of Science. / Spring Semester 2016. / March 31, 2016. / bycatch, deep-sea, giant isopod, mortality, post-release, shark / Includes bibliographical references. / Brendan Suneel Talwar defended this Thesis on March 31, 2016, Professor Directing Thesis; Edward J. Brooks, Committee Member; Don Levitan, Committee Member; Joseph Travis, Committee Member.

The effective conservation of threatened and endangered plants requires an understanding of population dynamics and the evaluation of factors that could reduce population growth. I constructed and analyzed a stage structured demographic model for Euphorbia telephioides, a threatened dioecious perennial herb, to determine the current status of three populations, compare projections of population growth using different methods, and determine the effects of pollen limitation in the population dynamics of this species. Dioecious plants are prone to pollen limitation due to their inability to self-pollinate. Studies indicate that pollen limitation reduces seed set in plants due to insufficient quantity or quality of pollen, which can reduce population growth rate due to the decrease in fecundity. I combined experimental tests for pollen limitation with construction and analysis of structured demographic models, to examine how increased levels of pollen limitation would affect population growth rates. Determining the current status of populations, and simulating the consequences of possible threats, such as pollen limitation, provides a quantitative basis for conservation actions. I compared deterministic and stochastic projections of a stage structured demographic model to examine how environmental variation affects population growth rates, and I examined the effects of parameterizing the model excluding demographic measures of randomly marked individuals in the population growth rates (Lambda). The majority of estimated lambdas and their 95% confidence intervals indicate that these three populations are projected to decline. Lambda estimated excluding randomly marked individuals overestimated population growth because adult plants had 100% survival. I did not find evidence of significant pollen limitation of fruit or seed production, and simulations of increased levels of pollen limitation reduce Lambda at a modest rate between 0.17% to 1.91%. The main advantage of constructing a structured demographic model is that these models allow us to integrate data on different stages of a complex life cycle. In the case of E. telephioides elasticity analysis indicates that increasing stasis of non-flowering plants could lead to increasing population growth rates. / A Thesis submitted to the Department of Biological Science in partial fulfillment of the Master of Science. / Fall Semester 2016. / November 2, 2016. / Euphorbia telephioides, Population ecology / Includes bibliographical references. / Alice Winn, Professor Directing Thesis; Joseph Travis, Committee Member; Nora Underwood, Committee Member.

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The research question posed in this study asks what qualities, characteristics and cultural significance need to be embodied within an urban environment that make the area worthy of conservation-oriented protection through laws and policies. The research question was explored through an assessment of the townscape of Vredehoek, an informally(1) proposed conservation area in Cape Town where there is a relatively high concentration of Art Deco buildings. The selection of Vredehoek as a laboratory within which to ask this question is due to the presence of contested opinions amongst various stakeholders and heritage-claimants about the cultural significance embodied within the built fabric of this place. This study aimed to identify what elements of the built environment of Vredehoek are of special interest, what qualities and characteristics these elements of special interest embody, to understand and articulate the values that inform these qualities, and to identify to whom these elements are valuable and why. Criteria were established with which to determine whether the identified qualities and values are special enough that when synthesised, the resultant significance of the place warrants protection through heritage area designation. The criteria developed with which to assess and evaluate proposed urban conservation areas, including Vredehoek, require that such environments need to embody cultural significance and characteristics informed by an urban history reflected in its authentic manifestations developed over time through continuity of use with a high townscape quality established primarily through the aesthetic unity of its component parts. Through historical research, the studying, mapping and analysis of the area's urban morphology, built environment and natural landscape, and the identification and evaluation of values held by heritage-claimants and views held by those critical of Vredehoek's proposed designation, evidence regarding the conservation-worthiness of Vredehoek has been assembled and assessed within the framework of criteria developed to evaluate heritage area designation. It has been found that the environment of Vredehoek does not embody high townscape quality nor does a strong aesthetic unity of its components exist. Furthermore, the area is not a richly layered environment reflecting continuity of use, the existence of cultural significance within the place is limited to a relatively small part of the townscape - a collection of Art Deco buildings demonstrating a moderate degree of architectural merit. Thus the environment of Vredehoek does not meet the criteria required for heritage area conservation.

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