Multi-temporal analysis of changes in vegetation distribution in the Great Fish River Game Reserve, Eastern Cape Province, South Africa :1982-2012
- Authors: Dikweni, Sipho
- Date: 2018
- Subjects: Climatic changes -- South Africa|zEastern Cape Biodiversity conservation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10511 , vital:35550
- Description: Great Fish River Game Reserve plays an important role in curtailing the ever-increasing biodiversity declines in Eastern Cape Province and South Africa at large. Though this area plays an important role in the conservation of natural biodiversity, it has been observed that it is undergoing considerable changes with regards to conditions and composition of vegetation cover. These changes signal a decline in the capacity of the Great Fish River Game Reserve to support wildlife population. In this study, remote sensing was used to investigate multi-temporal changes in vegetation distribution in this particular reserve over a period of 30 years (1982-2012). A supervised classification was carried out to classify four Landsat images including; Landsat TM, Landsat ETM and Landsat 8 imagery of 1984, 1992, 2002 and 2013 respectively to map historical and present vegetation conditions and distribution in the Great Fish River Game Reserve. A comparative examination of the classified images showed that there were significant changes in the composition and structure of vegetation with much of the palatable plant species being driven to extinction. The results showed that herbivory pressure inconjuction with climate variability has subsequently resulted in a decrease of the supporting potential of the reserve to sustain wildlife due to mortality of the most preferred plant species and abundant increase of non-palatable plant species. As grazing and browsing intensity increased, there was a decline in regenerative potential of the selected plant species by wild herbivores and successful increase in abundance of the non-palatable plant species. The results of this investigation suggest that the current increase in wildlife population will facilitate the deterioration of habitat condition to support wildlife up to the point of no recovery.
- Full Text:
- Date Issued: 2018
- Authors: Dikweni, Sipho
- Date: 2018
- Subjects: Climatic changes -- South Africa|zEastern Cape Biodiversity conservation
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10511 , vital:35550
- Description: Great Fish River Game Reserve plays an important role in curtailing the ever-increasing biodiversity declines in Eastern Cape Province and South Africa at large. Though this area plays an important role in the conservation of natural biodiversity, it has been observed that it is undergoing considerable changes with regards to conditions and composition of vegetation cover. These changes signal a decline in the capacity of the Great Fish River Game Reserve to support wildlife population. In this study, remote sensing was used to investigate multi-temporal changes in vegetation distribution in this particular reserve over a period of 30 years (1982-2012). A supervised classification was carried out to classify four Landsat images including; Landsat TM, Landsat ETM and Landsat 8 imagery of 1984, 1992, 2002 and 2013 respectively to map historical and present vegetation conditions and distribution in the Great Fish River Game Reserve. A comparative examination of the classified images showed that there were significant changes in the composition and structure of vegetation with much of the palatable plant species being driven to extinction. The results showed that herbivory pressure inconjuction with climate variability has subsequently resulted in a decrease of the supporting potential of the reserve to sustain wildlife due to mortality of the most preferred plant species and abundant increase of non-palatable plant species. As grazing and browsing intensity increased, there was a decline in regenerative potential of the selected plant species by wild herbivores and successful increase in abundance of the non-palatable plant species. The results of this investigation suggest that the current increase in wildlife population will facilitate the deterioration of habitat condition to support wildlife up to the point of no recovery.
- Full Text:
- Date Issued: 2018
Estimating maize grain yield from crop growth stages using remote sensing and GIS in the Free State Province, South Africa
- Authors: Mditshwa, Sithembele
- Date: 2017
- Subjects: Crop yields Crops -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6016 , vital:29481
- Description: Early yield prediction of a maize crop is important for planning and policy decisions. Many countries, including South Africa use the conventional techniques of data collection for maize crop monitoring and yield estimation which are based on ground-based visits and reports. These methods are subjective, very costly and time consuming. Empirical models have been developed using weather data. These are also associated with a number of problems due to the limited spatial distribution of weather stations. Efforts are being made to improve the accuracy and timeliness of yield prediction methods. With the launching of satellites, satellite data are being used for maize crop monitoring and yield prediction. Many studies have revealed that there is a correlation between remotely sensed data (vegetation indices) and crop yields. The satellite based approaches are less expensive, save time, data acquisition covers large areas and can be used to estimate maize grain yields before harvest. This study applied Landsat 8 satellite based vegetation indices, Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI) and Moisture Stress Index (MSI) to predict maize crop yield. These vegetation indices were derived at different growth stages. The investigation was carried out in the Kopanong Local Municipality of the Free State Province, South Africa. Ground-based data (actual harvested maize yields) was collected from Department of Agriculture, Forestry and Fisheries (DAFF). Satellite images were acquired from Geoterra Image (Pty) Ltd and weather data was from the South African Weather Service (SAWS). Multilinear regression approaches were used to relate yields to the remotely sensed indices and meteorological data was used during the development of yield estimation models. The results showed that there are significant correlations between remotely sensed vegetation indices and maize grain yield; up to 63 percent maize yield was predicted from vegetation indices. The study also revealed that NDVI and SAVI are better yield predictors at reproductive growth stages of maize and MSI is a better index to estimate maize yield at both vegetative and reproductive growth stages. The results obtained in this study indicated that maize grain yields can be estimated using satellite indices at different maize growth stages.
- Full Text:
- Date Issued: 2017
- Authors: Mditshwa, Sithembele
- Date: 2017
- Subjects: Crop yields Crops -- Physiology
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/6016 , vital:29481
- Description: Early yield prediction of a maize crop is important for planning and policy decisions. Many countries, including South Africa use the conventional techniques of data collection for maize crop monitoring and yield estimation which are based on ground-based visits and reports. These methods are subjective, very costly and time consuming. Empirical models have been developed using weather data. These are also associated with a number of problems due to the limited spatial distribution of weather stations. Efforts are being made to improve the accuracy and timeliness of yield prediction methods. With the launching of satellites, satellite data are being used for maize crop monitoring and yield prediction. Many studies have revealed that there is a correlation between remotely sensed data (vegetation indices) and crop yields. The satellite based approaches are less expensive, save time, data acquisition covers large areas and can be used to estimate maize grain yields before harvest. This study applied Landsat 8 satellite based vegetation indices, Normalized Difference Vegetation Index (NDVI), Soil Adjusted Vegetation Index (SAVI) and Moisture Stress Index (MSI) to predict maize crop yield. These vegetation indices were derived at different growth stages. The investigation was carried out in the Kopanong Local Municipality of the Free State Province, South Africa. Ground-based data (actual harvested maize yields) was collected from Department of Agriculture, Forestry and Fisheries (DAFF). Satellite images were acquired from Geoterra Image (Pty) Ltd and weather data was from the South African Weather Service (SAWS). Multilinear regression approaches were used to relate yields to the remotely sensed indices and meteorological data was used during the development of yield estimation models. The results showed that there are significant correlations between remotely sensed vegetation indices and maize grain yield; up to 63 percent maize yield was predicted from vegetation indices. The study also revealed that NDVI and SAVI are better yield predictors at reproductive growth stages of maize and MSI is a better index to estimate maize yield at both vegetative and reproductive growth stages. The results obtained in this study indicated that maize grain yields can be estimated using satellite indices at different maize growth stages.
- Full Text:
- Date Issued: 2017
Multi-temporal analysis of urban land-use and land-cover patterns in Alice, Eastern Cape Province, South Africa
- Authors: Manyanye, Owen
- Date: 2017
- Subjects: Geographic information systems Land use -- Remote sensing Land cover
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8066 , vital:31506
- Description: South Africa is undergoing rapid urbanization coupled with fast demographic change in the major cities and towns. This economic shift leaves behind underdevelopment, particularly in the rural areas such as the Eastern Cape Province. Underdevelopment of rural Eastern Cape can be understood by revisiting the “native reserve policy” of the Union of South Africa (1910 –1948) and the separate development policies of the apartheid government (1948 –1994). These policies have induced landlessness in the rural Eastern Cape and the destruction of rural livelihoods, poverty and under-development of roads, housing, health, education and sanitation facilities, and constrained development of a sustainable local economy. This study was aimed at determining the temporal and spatial land-use / land-cover changes in and around Alice town in the Eastern Cape Province of South Africa by using multi-date remotely Landsat TM images covering 5 time slices for the years 1984, 1989, 1994, 1999 and 2009. This was done by using supervised classification to objectively reconstruct changes in land-use and land-cover by compiling time-series maps with four information classes and using the Kappa Coefficient to assess the accuracy of all map outputs. Results of this investigation point to significant changes in land-use and land-cover over the 25-year study period between 1984 and 2009 with built-up areas expanding by 3720 hectares from 3227 hectares in 1984 to 6947 hectares in 2009. This observation is important because it enhances our understanding of the dynamics of urban growth and provides useful insights that aid urban development planning and policy formulation. The research concludes by recommending the use time series remotely sensed imagery as a decision-support tool for urban and environment management.
- Full Text:
- Date Issued: 2017
- Authors: Manyanye, Owen
- Date: 2017
- Subjects: Geographic information systems Land use -- Remote sensing Land cover
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/8066 , vital:31506
- Description: South Africa is undergoing rapid urbanization coupled with fast demographic change in the major cities and towns. This economic shift leaves behind underdevelopment, particularly in the rural areas such as the Eastern Cape Province. Underdevelopment of rural Eastern Cape can be understood by revisiting the “native reserve policy” of the Union of South Africa (1910 –1948) and the separate development policies of the apartheid government (1948 –1994). These policies have induced landlessness in the rural Eastern Cape and the destruction of rural livelihoods, poverty and under-development of roads, housing, health, education and sanitation facilities, and constrained development of a sustainable local economy. This study was aimed at determining the temporal and spatial land-use / land-cover changes in and around Alice town in the Eastern Cape Province of South Africa by using multi-date remotely Landsat TM images covering 5 time slices for the years 1984, 1989, 1994, 1999 and 2009. This was done by using supervised classification to objectively reconstruct changes in land-use and land-cover by compiling time-series maps with four information classes and using the Kappa Coefficient to assess the accuracy of all map outputs. Results of this investigation point to significant changes in land-use and land-cover over the 25-year study period between 1984 and 2009 with built-up areas expanding by 3720 hectares from 3227 hectares in 1984 to 6947 hectares in 2009. This observation is important because it enhances our understanding of the dynamics of urban growth and provides useful insights that aid urban development planning and policy formulation. The research concludes by recommending the use time series remotely sensed imagery as a decision-support tool for urban and environment management.
- Full Text:
- Date Issued: 2017
Monitoring changes in vegetation distribution to ascertain the extent of degradation in the savannas of Nkonkobe Local Municipality, Eastern Cape, South Africa
- Authors: Masiza, Wonga
- Date: 2016
- Subjects: Savanna ecology -- South Africa -- Eastern Cape Land degradation -- South Africa -- Eastern Cape Vegetation management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2027 , vital:27598
- Description: Savanna degradation is an environmental problem occurring in most countries around the world and it poses threats to biodiversity conservation, the food industry, and other economic sectors. According to FAO, South Africa’s rangelands exhibit the highest rate of fragmentation in comparison to range ecosystems in neighbouring countries including Lesotho and Swaziland, and consensus among researchers is that communal rangelands are more degraded than commercial rangelands. Although researchers and communities have identified the occurrence of land degradation in communal savannas at a local scale, land degradation has been poorly estimated because little has been done to quantify the extent and dynamics of perceived and observed changes associated with land degradation. The main goal of this study is to provide empirical insights on the direction of changes in the communal savannas of Nkonkobe Local Municipality in order to inform policy formulation and implementation. Additional to the communal sites is a private farm included for comparative analysis of trends in communal and commercial savannas. Landsat imagery was used to map, assess, and quantify the extent of land degradation in Nkonkobe Local Municipality, over a period of 30 years between 1984 and 2014. Field investigations were undertaken in June 2015 to acquire reference data to guide supervised classification of Landsat images. Three algorithms (Mahalanobis-distance, Minimum-distance, and Maximum likelihood classification) were compared to identify a classifier that produced the best results. The maximum likelihood classifier produced the best results with classification accuracy levels of 95.24 percent, 89.66 percent, and 95.65 percent for Honeydale Farm, Thyume, and Sheshegu respectively. Regression analysis revealed that both communal and private lands have experienced statistically significant increases in bush encroachment and decreases in surface water. Communal savannas have been confronted more by expansion of built-up area, decrease in open grassland, abandonment of arable land, soil erosion, and a steady invasion by Acacia Karroo compared to the privately owned commercial farm. The land cover changes measured through this investigation suggest an environmental shift that threatens biodiversity and agricultural activity. The study provides empirically informed insights about the direction to which these savannas are changing with the hope that the findings will prompt formulation and implementation of effective policies.
- Full Text:
- Date Issued: 2016
- Authors: Masiza, Wonga
- Date: 2016
- Subjects: Savanna ecology -- South Africa -- Eastern Cape Land degradation -- South Africa -- Eastern Cape Vegetation management -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/2027 , vital:27598
- Description: Savanna degradation is an environmental problem occurring in most countries around the world and it poses threats to biodiversity conservation, the food industry, and other economic sectors. According to FAO, South Africa’s rangelands exhibit the highest rate of fragmentation in comparison to range ecosystems in neighbouring countries including Lesotho and Swaziland, and consensus among researchers is that communal rangelands are more degraded than commercial rangelands. Although researchers and communities have identified the occurrence of land degradation in communal savannas at a local scale, land degradation has been poorly estimated because little has been done to quantify the extent and dynamics of perceived and observed changes associated with land degradation. The main goal of this study is to provide empirical insights on the direction of changes in the communal savannas of Nkonkobe Local Municipality in order to inform policy formulation and implementation. Additional to the communal sites is a private farm included for comparative analysis of trends in communal and commercial savannas. Landsat imagery was used to map, assess, and quantify the extent of land degradation in Nkonkobe Local Municipality, over a period of 30 years between 1984 and 2014. Field investigations were undertaken in June 2015 to acquire reference data to guide supervised classification of Landsat images. Three algorithms (Mahalanobis-distance, Minimum-distance, and Maximum likelihood classification) were compared to identify a classifier that produced the best results. The maximum likelihood classifier produced the best results with classification accuracy levels of 95.24 percent, 89.66 percent, and 95.65 percent for Honeydale Farm, Thyume, and Sheshegu respectively. Regression analysis revealed that both communal and private lands have experienced statistically significant increases in bush encroachment and decreases in surface water. Communal savannas have been confronted more by expansion of built-up area, decrease in open grassland, abandonment of arable land, soil erosion, and a steady invasion by Acacia Karroo compared to the privately owned commercial farm. The land cover changes measured through this investigation suggest an environmental shift that threatens biodiversity and agricultural activity. The study provides empirically informed insights about the direction to which these savannas are changing with the hope that the findings will prompt formulation and implementation of effective policies.
- Full Text:
- Date Issued: 2016
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