Student Number : 7729948 - MSc dissertation - School of Animal, Plant and Environmental Sciences - Faculty of Science / As early as 1583 an ultramafic plant was described (Proctor & Woodell, 1975). Since the early 1900s a number of works documenting ultramafic vegetation in various parts of the world have been published (Proctor & Woodell, 1975). The vegetation of the Great Dyke, Zimbabwe was only described in 1965 (Wild, 1965). Much has been written since then, however. It was only as recently as 1989 that any work on ultramafic vegetation in South Africa was published (Morrey et al., 1989), possibly because ultramafic vegetation in the Barberton Greenstone Belt is not noticeably different from that of the surroundings and outcrops are much smaller than the Great Dyke. Studies since then have documented the flora of the ultramafic soils of the Barberton Greenstone Belt (BGB) (Morrey et al., 1992; Williamson, 1994; Balkwill et al., 1997; Williamson et al., 1997; Changwe & Balkwill, 2003; Williamson & Balkwill in prep.). There are around 40 larger outcrops of ultramafic soil in the BGB, the largest of which are shown in Figure 1.1, and to date 29 endemic taxa have been discovered, 5 of which hyperaccumulate Ni (Williamson & Balkwill, in prep). Using IUCN criteria 21 of these taxa have recommended conservation status in the vulnerable categories and four are data deficient. With a number of threatened taxa and scientifically interesting and potentially useful Ni hyperaccumulators on the South African part of the BGB, it was likely that there were additional endemic taxa in Swaziland or additional populations of species collected in South Africa. The ultramafic sites in Swaziland (Figure 1.2) range in altitude from 4750 m above sea level (Figure 1.3) in the south to below 2250 m in the Komati River valley (Figure 1.4), higher than the South African sites which range from 354 – 1648 m above mean sea level (Balkwill et al., 1997). The Swaziland sites thus provide an opportunity to discover the effect of altitude on the vegetation of ultramafic soils in the BGB. The higher sites are cooler than the lowveld sites, with frost at night in winter and even snow on rare occasions. Rainfall averages 127 to 152 mm per year, the highest rainfall being recorded at the higher altitudes, where frequent fog also supplements the rainfall (Compton, 1966). The Swaziland sites also show a range of topography with the lower altitude sites often situated on the slopes of mountains, but higher altitude sites comparatively level. Very little of the ultramafic area in Swaziland has any form of protection and half the area has already been lost to agriculture and forestry. A previous study (Witkowski et al., 2001) identified Kniphofia umbrina Codd. as a critically endangered ultramafic endemic. There was thus an urgent need to study the remaining ultramafic areas and document the vegetation before more of this unique and important habitat is lost, and possibly some endemic plant species too. High population growth, expanding forestry and black wattle encroachment could all impact negatively on the remaining diversity of the ultramafic areas.

Typescript Includes bibliographical references

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 86-93). Also available on the World Wide Web.

Reducing the cover of non-native species is one of the challenges of ecosystem restoration. The goal of this study is to identify native species traits that will increase native species cover and reduce non-native species cover in the first growing season at upland and wetland prairie restoration sites. Native and non-native prairie species were planted in the fall and harvested the following summer at both an upland and a wetland site. Native species traits, such as plant weight, leaf area, relative growth rate, leaf area ratio, leaf weight ratio, net assimilation rate, and specific leaf area were measured under laboratory conditions for 7- and 21-day old seedlings. Germination rate (laboratory) and phenology (field) were also measured. At the upland site, species with a large 7-day plant weight and a high germination rate also had high native cover in the field (P<0.00l, R��=0.83). At the wetland site, high 21-day leaf area, low 21-day leaf weight ratio, and high net assimilation rate predicted increased native cover in the field (P<0.00l, R��=0.87). An abundance of natives, as measured by native cover, native biomass, and number of individuals, likely results in fewer resources (light, nutrients, and water) available for the non-native species growth resulting in a reduction in the non-native cover. Intrinsic traits of native species also predicted the field performance of non-native species, although the amount of variation explained was lower than the amount of variation explained in the models that predicted native cover. In the upland site, native species with high leaf weight ratio (21-day) tended to have lower non-native cover in their field plots (P=0.087, R��=0.23). In the wetland site, the native species traits that predict non-native cover were low 21-day leaf area and high 21-day leaf weight ratio (P<0.00l, R��=0.46). These traits were similar to those that predicted native species cover at the wetland site. This study demonstrates the ability of species traits to predict field performance. Predictive models were generated using native species traits to select species for restoration that will increase native cover and decrease non-native cover in the first growing season. Traits can be measured for species not included in this study and the models generated can be used to predict the field performance of species at similar sites. / Graduation date: 2002

Thesis (M.S.)--Oregon State University, 2007. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: Judith Hough-Goldstein, Dept. of Entomology & Wildlife Ecology. Includes bibliographical references.

Not available / text

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 40-46). Also available on the World Wide Web.

Thesis (M.Sc.). / Written for the Dept. of Biology. Title from title page of PDF (viewed 2008/07/24). Includes bibliographical references.

Thesis (Ph.D.)--University of Western Australia, 2006.