No description available.

Includes bibliographical references. / Francolins (Francolinus spp.) are small to medium-sized, sedentary, Old World, partridge/quail-like, terrestrial gamebirds (Order Galliformes) that occupy diverse habitats ranging from dry/open/scrubby lowland and montane grasslands, bushveld and savanna/woodland to mesic montane/lowland forests and forest edges. Some francolins have complex distribution patterns and also are morphologically, ecologically and behaviourally diverse. At the start of this research, Francolinus Stephens, 1819 was considered a monophyletic galliform genus comprising 41 species (36 African and five Asiatic) divided among eight putatively monophyletic species groups and four taxonomically enigmatic species. However, different taxonomic revisions, especially post Hall's (1963) classic monograph, challenged the monophyletic status of the genus and that of some of its designated species groups differed markedly in the number of recognized subspecies. Furthermore, there was debate concerning the geographical origin of the genus: Asia versus Africa. Some of the early molecular research on a few exemplar francolin species based on partial mitochondrial Cytochrome-b DNA sequences and Restriction Fragment Length Polymorphisms (RFLPs) also challenged the monophyly of the genus and that of some of Hall's (1963) species groups. These findings suggested that francolins may form at least two distantly related lineages called 'patryse' (partridges) and 'fisante' (pheasants) by Afrikaans-speaking people. Patryse, or 'true' francolins, had been divided into as many as five genera (Francolinus, Ortygornis, Dendroperdix, Peliperdix, Scleroptila) and fisante, or spurfowls, all grouped into a single genus, Pternistis. Research in this thesis is based on: mitochondrial and nuclear DNA sequences (5554 base pairs), organismal and vocal characters of francolins and spurfowls.

No description available.

Harvesting of Aloeferox was estimated (in 1996) to bring in an annual income ofR4 million per year to rural communities alone - a vital source of income for full-time tappers who rely solely on Aloe ferox as their only form of financial survival. They are joined on occasion by casual-tappers who rely on tapping to supplement their incomes in times of hardship (Newton and Vaughan 1996). Landowner's also benefit by allowing harvesting on their land in exchange for a percentage of the harvest (Newton and Vaughan 1996). Trade in bitters sap or gel far outweighs that of other plant parts so care is taken by harvesters to keep the plants alive for future tapping. Leaves from only the lower third of the leaf rosette ( 10 - 15 leaves) are harvested, and 2 - 4 cm at the base of the leaves are left to prevent damage to vascular tissues (Newton and Vaughan 1996, Mac Farlane 2004). Populations are only harvested every 18 - 36 months allowing plants to recover from the loss of leaf material. Plants suffering from insect-infestation or disease are not harvested to avoid weakening the plant further and possibly causing death (Newton and Vaughan 1996). Effort is also made by landowners to relocate plants growing in areas they plan to transform and to monitor harvesting activities on their properties (Newton and Vaughan 1996). The vested interest in keeping the plants alive has inadvertently assured the preservation of populations at past harvesting levels although no formal conservation or resource management policy presently exists for A. ferox (Newton and Vaughan 1996). Effects of harvesting, which are not limited to the direct effect of leaf removal on the plant but include indirect effects - such as reduced reproductive output, reduced sap production and even trampling of recruits - have nonetheless raised concern for the long-term survival of populations (Newton and Vaughan 1996). This study addressed some of the indirect effects of harvesting on Aloe ferox on both population and individual plants levels. On the population level plant density, mortality, susceptibility to disease and sizeclass structure was compared between unharvested and harvested populations. On the individual plant level vegetative traits, flower production and sap production were compared between unharvested and harvested plants. One of few other studies on ecology of A. ferox by Hoffman (1988) assessed some of these characteristics for a population in Port Elizabeth, South Africa.

No description available.

This report investigates the potential for the culture of G. gracilis, an indigenous red alga, into the west coast mariculture farm Jacobs Bay Sea Products Pty. Various methods for cultivating Gracilaria as well as environmental parameters, which influence growth of Gracilaria, are disltussed below. From these optimal conditions for the polycultivation of G. gracilis are determined. Cultivation can take place either, in open waters, or on land. Open water systems are generally less intensive than land based operations. Open water systems can be either bottom planted or suspended. Suspended cultivation has the advantage of maintaining the plant thalli in optimal light intensities. Land based systems can make use of ponds, raceways or tanks. Tanks and raceways are more productive than ponds, but require higher flow rates and regulated nutrient regimes.

No description available.

The hybrid zone between Calendulauda albescens and C. barlowi, located near the Orange River, contains a wide range of phenotypically intermediate individuals. This study examines the mitochondrial DNA of some of these individuals to determine if possible introgression is occuring from C. albescens to C. barlowi. Mitochondrial DNA from 13 lark individuals found in the C. albescens/C. barlowi hybrid zone was analysed. A 358 base pair cytochrome-b sequence was obtained. The neighbour-joining phylogenetic tree obtained revealed two distinct clades, a C. albescens and C. barlowi clade. The C. barlowi clade was supported with a bootstrap value of 100. The C. albescens clade contained individuals of intermediate morphology, as represented by their hybrid index scores, indicating that intermediates between the two species contain the mitochondrial DNA of only one species, C. albescens. These results point at introgression from C. albescens to C. barlowi, with female C. albescens choosing to mate with male C. barlowi.

No description available.

The presence of the sporophytic 'Falkenbergia rufolanosa' phase of the invasive algal species Asparagopsis armata was first recorded in South Africa 57 years ago. The introduction of this highly invasive alga, of Australian/New Zealand origins, to Europe in the 1920's has since led to a number of recorded invasions by the gametophytic Asparagopsis phase in both the Mediterranean and Atlantic oceans. Recently however, a number of commercial uses for both phases of A. armata have been identified, which have given rise to industrial interest in the species as a candidate for commercial cultivation. Previous studies on European strains of F. rufolanosa and A. armata have identified a number of life history traits, which not only increase A. armata 's invasive ability, but also make it a useful species for commercial tank cultivation. However, different strains are known to have different environmental parameters which regulate their survival, growth and reproduction capabilities. This study investigated the growth of the South African strain of F. rufolanosa in culture, in response to different environmental variables, as well as the conditions necessary for tetrasporogenesis to occur, in order to assess its potential impacts, both as an invasive threat and as a species for commercial cultivation in South Africa.