The major histocompatibility complex (MHC) is a multigene family known to be the most variable gene group in vertebrates in terms of allelic diversity and gene number. Pathogen mediated selection is thought to be the major driving force behind the unusually high levels of MHC polymorphism in natural populations. In this study the relationship between MHC class I diversity and blood parasite infection intensity is explored in a population of black sparrowhawks (Accipiter melanoleucus). The species is of particular ecological and evolutionary interest as black sparrowhawks display a discrete polymorphism in plumage pattern across its range, occurring as a light and dark morph. It is well established in birds that carotenoïd and melanin-based pigmentation patterns are often associated with parasite resistance. In this study, functional variation at the peptide binding region (PBR) of MHC class I loci is investigated to explain individual variation in blood parasite infection in black sparrowhawks. Using DNA sequence data together with individual estimates of blood parasite load (for Haemoproteus nisi and Leucocytozoon toddi); the study tested the relationship between (i) allelic diversity and individual parasite load and (ii) specific alleles and individual parasite load using a Generalized Linear Model framework. Seven different, putatively functional, MHC class I alleles were identified. Number of alleles per individual ranged from one to three in individuals infected with H. nisi, whereas individuals infected with L. toddi had either two or three different alleles. A significant positive association was found between H. nisi infection intensity and MHC allele Acme_BF2*03. No significant association was found between L. toddi infection intensity and a specific allele. The results reported support the role of pathogen mediated selection of genetic variation at evolutionary relevant MHC genes through rare allele advantage. By characterizing the variation at MHC class I loci and testing for a relationship with parasitemia, it is now possible to elucidate the mechanisms and significance of MHC molecular adaptation in the black sparrowhawk.

Over-exploited fisheries result in global economic losses and can lead to the degradation of marine ecosystems. Commercial and recreational fisheries have grown substantially over the past decades placing fish stocks under increasing pressure. Fisheries management aims to conserve and restore stocks to economically and environmentally sustainable levels. Stock assessments are mostly based on analyses of fishery-dependent data, however, this practice often neglects uneconomically important species, making ecosystem approaches to fisheries management challenging. Competitive recreational angling has the potential to provide accurate and consistent records of catch and effort data for a variety of unassessed fish species as well as data for currently assessed commercial species, but without the market influence on targeting. The data from five boat based recreational competitions in the Western Cape were studied. Records for the competitions varied in length with the longest dataset from running from 1994 to 2014, and the shortest from 2003 to 2014. The competitions were divided into three inshore and two offshore groups with each targeting different assemblages of fish. In total 38 species of teleost were caught, but at least 90% of the total catch for each competition was comprised of seven species or less. Catch composition was determined for each competition and the standardised catch per unit effort (CPUE) of the ten most abundant species across the competitions were assessed. CPUE trends for red roman, snoek and geelbek were comparable to commercial fishery-dependent CPUE data. The targeting of specific species in the multi-species fishery noticeably influenced CPUE values. Catch limits resulted in lower estimations of the CPUE for snoek, and potentially for red stump nose. Boat based competition data is accurate and consistent enough for the extraction of abundance indices for certain species. Further work on these data may involve the standardisation of CPUE values to account for targeting in the multi-species fishery. With a large number of boat based competitive anglers in the country, there is a scope for using these data for stock assessments, either as stand-alone data sources, or as an adjunct to well-established commercial catch time-series.

No description available.

Includes bibliographical references. / Providing an economic case for establishing new protected areas and demonstrating how conservation enhances human well-being is becoming necessary to reinforce moral arguments for biodiversity protection. Accordingly; this study aimed to assess whether the spatial distribution of priority areas changes in accordance with gains in economic-efficiency when ecosystem service benefits are explicitly considered. Using the site-selection software Marxan, priority areas for South Africa were identified under four scenarios, two of which incorporated a spatial cost benefit analysis of the opportunity costs and ecosystem service benefits associated with conservation. Additional scenarios assessed how reserve design and costs changed when communal-land agriculture and resource use were weighted to account for the social costs of conservation. Opportunity costs were spatially variable and greatest in regions where mixed commercial farming was practiced. Economic benefits exceeded costs in the western interior, northern regions and along the eastern coastline. These areas contracted when ecosystem service benefits were more conservatively estimated by applying the principle of additionality. There was minimal to moderate spatial agreement between the scenarios (0.12 < κ < 0.55).When economic benefits were considered, areas that made more economic sense from a conservation management perspective were prioritized. These changes in spatial distribution were associated with gains in economic efficiency. The cost: benefit ratio was ca. 10 times greater than when no economic variables were considered (scenario 1 = 10.44 vs. scenario 4 = 1.15). When heavy weightings (> 100) were applied, the reserve systems became dispersed (R = 0.91 (for weighting factor of 10), R = 0.52 (for weighting factor of 1000)) in the former homelands and more costly overall (difference of R2.95B between the extremes). Considering the economic benefits of conservation changes the spatial distribution of priority areas and improves their economic efficiency. Disregarding economic benefits may compromise the implementation potential of priority areas, particularly when the economic benefits of competing land-uses are brought to the table. Furthermore, it is important to explicitly consider the social costs of conservation and consider resettlement or compensation costs among the trade-offs.

Includes bibliographical references. / Domestic cats (Felis catus) are abundant generalist predators that exploit a wide range of prey within and adjacent to the urban matrix. Cats are known to have contributed to the extinction and endangerment (mostly on islands) of a number of indigenous species, including birds, small mammals, reptiles and amphibians. Most research on this important topic has been carried out in the developed world, predominantly in Australia, New Zealand, the U.K., the U.S. and Canada with only four studies carried out in Africa. Of these, two studies in Cape Town suggest that domestic cats have a big impact on wildlife but these studies may have underestimated predation because they failed to account for the proportion of prey not returned to participants’ homes. In this study I used kitty-cams in an attempt to provide a prey correction factor for urban cats in Cape Town, South Africa. I investigated hunting of wildlife by free-ranging domestic cats in Newlands, a suburb of Cape Town, South Africa over 5 weeks in 2013. I monitored 13 cats (6 deep-urban and 7 urban-edge) by questionnaire survey, asking cat owners to record all prey items returned by their cats. A total of 43 prey items were returned, 42% of which were small mammals, 30% invertebrates, 12% reptiles, 9% amphibians and 7% birds. Combining these data with two similar survey studies carried out in Cape Town I estimated that a total of 118 cats caught an average of 0.04 prey items per cat per day. Ten of the 13 cats were also monitored for 3 weeks using kitty-cam video cameras. Participating cats wore a video camera and all activity was analysed for prey captures and behavioural activity patterns.

The Maputaland Centre of Endemism (MCE), an area stretching from northern-east KwaZulu-Natal in South Africa to the Limpopo River in southern Mozambique, holds more than 2,500 native plant species. Of those, over 203 are endemic or near endemic to this area. However, the current high human population density in MCE, coupled with high population growth, has increased the pressure on the natural resources of the region and threatens the natural vegetation and plant diversity. Therefore, there is a pressing need to fully understand the threats faced by the Maputaland endemic and near endemic plants and to carry out appropriate conservation actions. In this context, the main aim of the study was to document the distribution of the MCE endemic plant species, with particular emphasis on southern Mozambique. The study also aimed to document the threats to these species and to assess their global conservation status using the International Union for Conservation of Nature (IUCN) Red List Categories and Criteria. This was done by gathering historical species distribution data from herbarium specimens and by assessing their current distribution in the field. In addition, a land cover data set was used to evaluate the level of habitat transformation over time. As a result, 13 endemics were assessed, 11 of these species for the first time. Of the 13 species assessed, two were assessed as Least Concern, five as Vulnerable, four Endangered, one Critically Endangered, and one possibly Extinct. MaxEnt models were used to model the potential distribution of the species assessed and to identify hotspots and priority areas for conservation. The priority areas represent sites of greatest overlap, where 50% of all modelled species overlap in their suitable potential distributions. With this approach, priority areas were identified that can be used in conservation planning, protected area expansion, or other conservation projects. This analysis showed that the highest number of the study species (>7) is concentrated within the Licuati Forest, located south of Maputo in Matutuine District, southern Mozambique. The main threat to this area is charcoal extraction and although none of the endemic species are targeted for charcoal production, the impact of the associated habitat destruction on the endemic species is expected to cause severe declines. It is recommended that studies on the dynamics of the Licuati Thicket vegetation are needed, particularly in terms of the impact of charcoal extraction on the endemics.

The impacts of biological invasions on native avian diversity have been the subject of many studies in Africa. However, a holistic synthesis of available information from different taxa and their impacts on native birds is lacking. From published information, I analysed the negative and positive effects of biological invaders on native African birds from five taxa: plants, invertebrates, fish, mammals and birds. In order to assess functional gains and losses, native birds were categorized into their functional guilds defined by their primary diet. I limited my scope to mainland Africa at the biome level. ArcView GIS 3.3 software was used to map locational data of impacts within the major biomes. The results indicate that a minimum of 572 native birds are negatively impacted by invasive species from the five taxa. This represents ca 29% of all the bird species in Africa. In contrast, only 191 species of native birds benefited from such invasions. Birds whose diet was primarily insects were disproportionally impacted. The majority of the impacts were caused by invasive plants. At the biome level, the greatest numbers of native birds impacted were in the Montane grassland and shrubland biome. It is predicted that native birds will continue to lose more than they gain from biological invasions in the continent.

The study focused on avian species' responses to high ambient temperature. Ambient temperature is a variable to which birds are particularly sensitive and which climate-change models predict will increase disproportionately rapidly in southern Africa's hot deserts, especially the Kalahari.

Includes bibliographical references. / In the arid and semi-arid western parts of southern Africa, Aloe dichotoma Masson, a long-lived succulent tree species, is thought to be responding to anthropogenic climate change. However, differences in response across its distribution are likely to be related to rainfall seasonality. This study investigated change in ten Aloe dichotoma populations within winter and summer rainfall zones in South Africa and southern Namibia. Using repeat photography over a timespan of approximately 30 years, demographic patterns, population dynamics (including mortality, recruitment and overall population change) and growth were assessed and modelled with climatic variables. Long-term patterns of recruitment and longevity were also investigated by using individual plant growth data to reconstruct recruitment histories for each population. Finally, the influences of climatic conditions on recruitment were evaluated by superimposing historical rainfall and temperature data. Differences in response between rainfall zones are clearly evident throughout. Generalised linear models revealed lower mortality, higher recruitment and positive population change at winter rainfall sites, while summer rainfall sites showed negative population change. Growth data revealed more rapid growth in height of juveniles than adults, and slower growth in height in the winter rainfall zone, most likely related to differences in tree architecture. It is evident that biotic and anthropogenic factors such as herbivory, nurse plants and theft are likely to moderate observable patterns as opposed to driving them. Recruitment modelling suggested that A. dichotoma attains a maximum age of 300 to 350 years, and revealed recent recruitment peaks in the winter rainfall zone and peaks around the turn of the 19th century in the summer rainfall zone. Changes in temperature and rainfall are likely to be the main drivers. Rising temperatures within the last century may have driven increased recruitment and low mortality in the cold-limited winter rainfall zone, while decreasing rainfall within the summer rainfall zone, combined with increasing temperatures, may explain this region's low recruitment and high mortality. The advancement of knowledge of broad spatial and temporal patterns in A. dichotoma and the likely causes, coupled with fine-scale future studies, will enable more detailed prediction of the species' response to future global change.

Includes bibliographical references (p.36-44). / Whilst the phylogenetic relations of gamebirds are now well understood, there is a great lack of consensus on their biogeographical relationships. It has been suggested that the basal galliform clades, namely the megapodes from Australasia and the cracids from South and Central America, have their origins in the northern hemisphere and have colonised the southern hemisphere more recently. Those in favour of a Northern Hemisphere origin suggest that stem galliforms originated only after the Cretaceous-Tertiary mass extinction event.