Bibliography: leaves 126-128. / The sub-Antarctic Prince Edward Island group, consisting of Marion Island and Prince Edward Island (Fig. 1), was annexed by South Africa in 1947-1948 and subsequently declared a nature reserve. Isolated oceanic islands have always presented interesting opportunities for biological research on both the marine mammals and birds which use them for breeding purposes and the resident, often specially adapted, fauna and flora which colonise them. The ice-capped, windy and wet Marion and Prince Edward Islands are young volcanic islands, less than 300000 years old, and house a considerably less diverse biota than the much older Crozet and Kerguelen sub-Antarctic Archipelagos (Van Zinderen Bakker, 1971). In view of the relative simplicity, small size and isolation of the Marion Island ecosystem one of the major goals of the South African Scientific Committee for Antarctic Research (SASCAR) has been to provide a comprehensive model describing the functioning of the system. Thus since the start of official biological research in 1965 many studies have been undertaken in the fields of ornithology, plant ecology, mammalogy and limnology. Marine biological research has been relatively neglected and at the outset of the present project the only work available on the Marion Island littoral fauna, apart from various taxonomic reports, was that of De Villiers (1976) who described species composition and zonation patterns of the shores. The present study, along with Mr Peter Haxen's research on the inshore macro-algae, was aimed at bridging the gap in our knowledge of the intertidal and shallow subtidal communities of Marion Island.

Includes bibliographical references (leaves 68-84). / The onset of activity in animals restricted to being active for only part of the day, is one of the most fundamental aspects of their biology. Onset of activity is likely subject to several factors including presence/absence of predators and the vagaries of environmental conditions at the time of emergence. The aim of my study was to test several hypotheses accounting for differing emergence times amongst sympatric insectivorous bat species.

Bibliography: pages 67-72. / Phylogenetic relationships among species within the beetle genus Onymacris (Coleoptera Tenebrionidae) are identified using phenetic and cladistic approaches. Phylogenetic results from cladistic analyses proved to be more robust than those derived with phenetic approaches. However, phenetic analyses proved to be useful in identifying possible interspecific hybridization. Two monophyletic subgenera are recognized. The subgenus Melanonymacris comprises O. lobicollis, O. rugatipennis, O. paiva, O. boschimana, O. multistriata, O. hottentota and O. plana, all of Which have black elytra. The subgenus Onymacris comprises O. langi, O. marginipennis, O. brainei, O. candidipennis and O. bicolor, all of which have pale-coloured elytra, and two species with black, 'bullet-shaped' elytra, O. laeviceps and O. unguicularis. The resulting cladogram and the characters and synapomorphies underpinning it are compared with those from an independently conducted study (Penrith 1984). The implications of the cladogram are discussed in the lignt of the tenets of vicariance biogeography and the constraints of adaptation to the extreme desert environment.

Bibliography: p. 137-145. / Although broad wetland classifications systems are available internationally, a comprehensive wetland classification system, which can be used for both desktop and field analyses, is lacking in South Africa but is required by the South African National Water Act (36 of 1998). Wetlands within the Western Cape were selected from different bioregions and wetland regions. In this project geomorphological characteristics (drainage patterns, landform), hydrological pattern and timing of water availability, were recorded during winter and summer for each studied wetland. Water samples were also collected at the wetlands and analysed for ion and nutrient concentrations and samples of organisms were collected for identification. Multivariate cluster and multidimentional scaling analyses of the chemical and biotic data were used to aid identification of wetland groups. A hierarchical classification system was developed using drainage patterns ( endorheic or exorheic systems) as the primary defining characteristic, followed by wetland landform and hydrological regime as the secondary and tertiary characteristics for identifying wetlands.

Includes abstract / Includes bibliographical references (leaves 124-133). / Spontaneous succession, as a method to restore degraded riverine habitats, was assessed for three different components of the Silvermine River ecosystem over one year. These were the state of the physical habitats (biotopes) available to aquatic organisms, changes in the community composition of riparian vegetation, and changes to aquatic macroinvertebrate assemblages present in the river. Data were collected during two successive summer-sampling periods (200 I and 2002) at three study sites along the river. Site I was situated in the mountain stream zone, while Sites 2 and 3 were situated in the foothills. Changes in the riverine ecosystem and its associated habitats were compared to reference condition data for each of the three components from each study site. There were no large changes to the macro-channel banks of the river over the one year study, other than where a meander cut-off occurred at Site 2. Changes over the year in the proportions of flow at the three sites revealed a lack of faster-flow types, which would normally characterise mountain stream and foothill reaches, at all three study sites. Measurements of the proportions of substratum types at the three sites revealed there was an unusually high proportion of fine substratum types present. In the foothills, this was attributed to erosion of the unstable bank at Site 2, which continued to deposit an excess of fine sediment that was transported downstream. In the vegetation study, most species that came to dominate the mountain stream (Site I) and the foothill (Sites 2 and 3) riparian communities emerged from the seed bank within the first two years after the fire. Thus, using the presence or absence of characteristic riparian vegetation species it is possible to determine whether there is a need to augment the recovery process after two years. The aquatic macroinvertebrate communities of the mountain stream differed clearly from those in the foothill. The differences were attributed to a combination of the channel type and the longitudinal position of the sites along the river, both of which dictated the physical habitats available. There were clear differences in the potential for recovery at each of the three study sites. It was shown that non-intervention will not support successful recovery in the short to medium term for any of the measured three components of this river. A blanket policy of non-intervention cannot address site-specific differences, be they natural or artificial, which pose different challenges to restoration. There were zonal differences in the availability of substrata and flow types. There were also other differences that were attributed to water abstraction and the presence of different woody exotic trees. Recovery of the mountain stream was being hampered by the presence of the reservoir and the history of water abstraction while recovery of the foothill was being retarded by erosion from the massive sediment deposit at Site 2. Plans to restore the river, that took into account these inter-site differences, were proposed.

Includes abstract. / Includes bibliographical references (leaves 50-55). / The results showed that the difference in the weed density was insignificant, indicating that biological and chemical control were both effective in the management of S. elaeagnifolium. However biological control was shown to be more economically beneficial than chemical control, since there was a net gain as a result of lower costs using L. texana beetles. Further research is needed to determine the effectiveness of L. texana and damage caused by S. elaeagnifolium on expected yield to conduct a full cost-benefit analysis.

Includes bibliographical references. / The South African Cirripedia (Thoracica) are reviewed for the first time in 88 years, since that of Barnard (1924). Data collection consisted of records from the South African Museum, previously published literature, and specimens collected in the field. The current state of knowledge of the taxon in South Africa has been considerably raised. Thirteen new records are added to the fauna, of Which 84.6% are cosmopolitan and 15.4% introduced species. This raises the total number of South African Cirripedia (Thoracica) to 86, of which 64.06% are cosmopolitan, 11.24% introduced and 24.7% endemic. Excluded from this, are three unknown species, which are likely to be new to science. Descriptions of these species will be undertaken outside of this thesis and published; however, they were classified as endemic and included in the analyses presented in Chapter three. Eleven of the new fauna can be described as "offshore benthic" and represent well known deep-water taxa.

This study reports the first characterisation of the embryonic bat limb transcriptome, allowing the identification of novel candidate genes that were differentially expressed between the bat hand and foot plate. These genes may have played important roles in the evolution of the bat wing and hindlimb. The reproduction and development of an African bat species, Miniopterus natalensis, was characterised and three maternal features (mass, belly size and plasma progesterone levels) examined as potential predictors of embryonic stages of development. Belly palpitation was found to be a useful field method to distinguish between non-pregnancy, early development or late development in female bats. A microarray analysis between the hand and foot plates of CS 16 and CS 17 bat embryos, and the hand plates of E 13.5 mouse embryos, revealed high correlation between the transcriptomes of the bat autopods and the mouse hand plate (r > 0.88) and among all the bat autopods (r > 0.98). However, ten genes were found to be differentially expressed in both the CS 16 and the CS 17 bat hand plate as compared to the mouse hand plate while only three genes were identified as being significantly differentially expressed between bat foot plates and mouse hand plates. A comparison between the bat hand and foot plates identified fifteen genes that were differentially expressed at the stage CS 17 stage and six at the stage CS 16. Closer examination of gene families involved in limb development revealed novel expression of genes in the retinoic acid (RA) pathway, and the Hoxd family. This included the apparent co- regulation of the 5' Hoxd genes (Hoxd10, 11, 12 and 13). Of the genes characterised in bat limb development (Hoxd13, Bmp2, Fgf8 and Prrxl), higher mRNA transcript levels in the CS 17 bat hand plate relative to the mouse hand plate was found for Hoxd13 (FC = 2.6) and Prrxl (FC = 1.8). These differences were also found in a comparison to the CS 17 bat foot plate (Hoxd13: FC = 1.4; Prrxl: FC = 1.4). A potentially novel transcript of Meis2, a gene important in specifYing the proximal-distal (P-D) axis of the limb, was noted for its high fold changes in the bat hand plate as compared the foot plate (CSI7: FC = 7.0; CSI6: FC = 2.2) and the mouse hand plate (FC = 13.1).

This thesis comprises two major sections: an assessment of the incidence of plastic particles at sea and in seabirds {Chapters 1-3), and an investigation of the postulated effects of plastic ingestion on seabirds (Chapters 4-7). The incidence of plastic at sea was recorded from neuston trawls performed monthly at 120 sampling stations off the southwestern Cape, South Africa, during 1977-78. The types of plastic particles collected are described, and the temporal and spatial distribution patterns of plastic pollution are discussed. Ingested plastic was recorded from 36 of 60 seabird species sampled. The effect of different sampling techniques on the incidence of plastic is discussed. The frequencies of occurrence of plastic colour-types in birds are compared with those of particles collected at sea in neuston trawls. Pale particles were under-represented in all species, but the disparity was less for small than for large species, which may account for the higher incidence of ingested plastic in small than in large species.

Bibliography: leaves 146-157. / Temporal variation in the diet and feeding intensity of snoek (Thyrsites atun), a top predator of commercially exploited pelagic clupeoids, was investigated in the Southern Benguela Upwelling System.