No description available.

No description available.

Please read the abstract in the section, 00front, of this document / Dissertation (MSc (Botany))--University of Pretoria, 2008. / Plant Science / unrestricted

The thesis deals with the differences in floristic composition of the vegetation in abandoned villages in the Slavkovský les forest and surrounding open landscape. Due to complex historical events, the villages were abandoned and demolished by the army. Vegetation survey took place in 13 completely destroyed villages, and since the vegetation in villages consists of a mixture of woody and treeless cover, the reference vegetation in the surroundings was selected to include both types of habitats. Total number of species, number of families, Ellenberg indicator values, number of archaeophytes and neophytes and representation of life forms were compared for the floras of villages and their surroundings. The flora of villages had more neophytes, phanerophytes and higher indicator values for nutrients and soil reaction. Species' positive fidelity and percentage frequency were calculated from the synoptic table. Indirect ordination plot (NMDS) and PERMANOVA test confirmed the differences between floristic composition in destroyed villages and their vicinity. The second part of the thesis explores the differences between floristic composition of plant communities by Heracleum mantegazzianum in the same two types of habitats. Based on 50 phytosociological relevés, the total number of species, number of...

<p>The objectives of this thesis are to assess: to what degree have natural resources deteriorated in a grazing area in northern Namibia, how do perceptions of environmental change held by local stakeholders there, correspond to scientific assessments, and how do these relate to national estimates? Analysis of the process of developing national indicators for monitoring of land degradation concluded that specific indicators should be developed on national level, and in some instances even on local level as there are no universal causes of land degradation. According to farmers overgrazing and low rainfall since the early 1990s cause negative environmental changes in the study area, partly confirming findings from national monitoring. Results also suggest that: less grazing outside the study area, improved access, permanent water supply, and fencing of large areas, also contributed. Results show that improved water supply was the most important factor. Investigation of the influence of permanent water points on grazing resources showed that perennial grasses are replaced by less palatable annual grasses as far as 6 km from water points along a water pipeline. No significant grazing induced changes in grass composition were observed around privately owned wells. Private ownership seems to be a key factor preventing over-utilization of grazing resources around the latter. A remote sensing study using Landsat TM imagery identified bare ground, saltpans and grassland with a fair accuracy. Separation of woodland from shrubland and shrubland from grassland was less accurate using supervised classification. The results show that the soil adjusted vegetation index provides valuable information about variations of green biomass over time in semi-arid environments. However, it is suggested that satellite based investigations should be supported by thorough ground based assessment due to the influence of underlying soil in this environment.</p>

The objectives of this thesis are to assess: to what degree have natural resources deteriorated in a grazing area in northern Namibia, how do perceptions of environmental change held by local stakeholders there, correspond to scientific assessments, and how do these relate to national estimates? Analysis of the process of developing national indicators for monitoring of land degradation concluded that specific indicators should be developed on national level, and in some instances even on local level as there are no universal causes of land degradation. According to farmers overgrazing and low rainfall since the early 1990s cause negative environmental changes in the study area, partly confirming findings from national monitoring. Results also suggest that: less grazing outside the study area, improved access, permanent water supply, and fencing of large areas, also contributed. Results show that improved water supply was the most important factor. Investigation of the influence of permanent water points on grazing resources showed that perennial grasses are replaced by less palatable annual grasses as far as 6 km from water points along a water pipeline. No significant grazing induced changes in grass composition were observed around privately owned wells. Private ownership seems to be a key factor preventing over-utilization of grazing resources around the latter. A remote sensing study using Landsat TM imagery identified bare ground, saltpans and grassland with a fair accuracy. Separation of woodland from shrubland and shrubland from grassland was less accurate using supervised classification. The results show that the soil adjusted vegetation index provides valuable information about variations of green biomass over time in semi-arid environments. However, it is suggested that satellite based investigations should be supported by thorough ground based assessment due to the influence of underlying soil in this environment.

Thesis (M. Sc. (Botany)) -- University of Limpopo, 2019 / The Woodbush Granite Grassland (WGG) is the most threatened vegetation type in Limpopo Province of South Africa. However, it has a high conservation value, because few examples of this vegetation type remain in southern Africa. Unfortunately, a large part of it is not formally conserved, making this the vegetation type most urgently in need of conservation. The study aimed at mapping transformation of the WGG, identifying species of conservation importance, and providing a management plan required for maintenance of the WGG. The objectives of the study included compiling a transformation map for the WGG, which also involved describing the remaining patches of the WGG that are in a natural or near-natural state. It also provides information on species of conservation importance, medicinal plants and threats to the WGG. On the four main study sites (Iron Crown Grassland, Haenertsburg Grassland, Ebenezer Dam Nature Reserve Grassland, and Ebenezer Dam Perimeter Grassland), quadratic plots were randomly set with a size of 25 x 25 m, and subplots of 1 x 1 m. Vegetation mapping was done during summer and winter. At each plot data was collected on all plant species occurring within the quadrat. A cover score was assigned to each plant species. A modified Braun-Blanquet data collection sheet was employed to obtain baseline data. For transformation mapping GeoTerra Image (GTI), land cover data were extracted for the WGG, using the modelled boundary as a mask, with 5 categories of transformation defined. Of the surveyed sites, the Ebenezer Dam Nature Reserve Grassland has the highest number of species, while the Haenertsburg Grassland contained the most endemic species of conservation importance. Rare species such as the Aloe zebrina, which does not occur in any formally protected area, and medicinal plants such as Athrixia phylicoides, occur on the WGG. All sites have importance with regard to WGG conservation. Identified threats include the spread of alien invasive plants, uncontrolled collection of medicinal plants, urban development, and poorly timed anthropogenic fire. vi The WGG underwent transformation to other land classes. Grassland clearing for plantations and cultivation were the main causal factors behind the observed WGG losses, with a total of 55.25% transformed. Transformation by afforestation is considered irreversible. It is concluded that the WGG is of conservation importance, and that some of it has been transformed to exotic timber plantations. The grassland is under various threats; therefore it is recommended that: (1) The proposed management plan provided in this study be adopted, (2) further research on the WGG be done on medicinal plants, (3) phytosociological and floristic studies be conducted and, (4) the effects of fire and alien invasive plant species on the grassland be investigated.

MEVNSC / Department of Geography and Geo-Information Sciences / Vegetation is one of the most important renewable natural resources to play a role in the preservation of the environment and biodiversity. Various land use activities such as urbanization, population growth and other anthropogenic activities, as well as climate change have been some of the major drivers which alter vegetation cover and contribute to biodiversity loss. This research study uses remote sensing and Geographical Information System to quantify vegetation and land cover change in Makhado over a five-year period (2007 - 2012). This study used multi-temporal satellite image data to identify the dynamic pattern of vegetation change and the negative impacts it has on the environment. The research uses remote sensing techniques and GIS software to analyse data. In addition, satellite imageries were used to study the spatial and temporal distribution of vegetation. The results of the study show that settlement areas have been on a stable positive and mostly uncontrolled expansion from 17.73% of the study area in 2007 to 30.52% in 2012. Vegetation on the other hand, has been on a steady decline, from 10.65% in 2007 to 5.92% in 2012, as well as the ecosystems quality on which biodiversity depends for their existence and to a greater extent the climate conditions, with an increase in temperature, methane, nitrous oxide and carbon dioxide. The monitoring of vegetation change can play a vital role in knowledge generation, best practices and as well as Environmental Monitoring and Evaluation which can be abated in the near future. This study recommends that the South Africa Government and public agencies concerned develop policies and strategies to bring about balanced, coordinated and sustainable development in the municipality and its district.