Estimation of woody plant species diversity during a dry season in a savanna environment using the spectral and textural information derived from WorldView-2 imagery
- Fundisi, Emmanuel, Musakwa, Walter, Ahmed, Fethi B., Tesfamichael, Solomon G.
- Authors: Fundisi, Emmanuel , Musakwa, Walter , Ahmed, Fethi B. , Tesfamichael, Solomon G.
- Date: 2020
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/435727 , uj:37768 , Citation: Fundisi E, Musakwa W, Ahmed FB, Tesfamichael SG (2020) Estimation of woody plant species diversity during a dry season in a savanna environment using the spectral and textural information derived from WorldView-2 imagery. PLoS ONE 15(6): e0234158. https://doi.org/ 10.1371/journal.pone.0234158
- Description: Abstract: Remote sensing techniques are useful in the monitoring of woody plant species diversity in different environments including in savanna vegetation types. However, the performance of satellite imagery in assessing woody plant species diversity in dry seasons has been understudied. This study aimed to assess the performance of multiple Gray Level Co-occurrence Matrices (GLCM) derived from individual bands of WorldView-2 satellite imagery to quantify woody plant species diversity in a savanna environment during the dry season. Woody plant species were counted in 220 plots (20 m radius) and subsequently converted to a continuous scale of the Shannon species diversity index. The index regressed against the GLCMs using the all-possible-subsets regression approach that builds competing models to choose from. Entropy GLCM yielded the best overall accuracy (adjusted R2: 0.41−0.46; Root Mean Square Error (RMSE): 0.60−0.58) in estimating species diversity. The effect of the number of predicting bands on species diversity estimation was also explored. Accuracy generally increased when three–five bands were used in models but stabilised or gradually decreased as more than five bands were used. Despite the peak accuracies achieved with three–five bands, performances still fared well for models that used fewer bands, showing the relevance of few bands for species diversity estimation. We also assessed the effect of GLCM window size (3×3, 5×5 and 7×7) on species diversity estimation and generally found inconsistent conclusions. These findings demonstrate the capability of GLCMs combined with high spatial resolution imagery in estimating woody plants species diversity in a savanna environment during the dry period. It is important to test the performance of species diversity estimation of similar environmental set-ups using widely available moderate-resolution imagery.
- Full Text:
- Authors: Fundisi, Emmanuel , Musakwa, Walter , Ahmed, Fethi B. , Tesfamichael, Solomon G.
- Date: 2020
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/435727 , uj:37768 , Citation: Fundisi E, Musakwa W, Ahmed FB, Tesfamichael SG (2020) Estimation of woody plant species diversity during a dry season in a savanna environment using the spectral and textural information derived from WorldView-2 imagery. PLoS ONE 15(6): e0234158. https://doi.org/ 10.1371/journal.pone.0234158
- Description: Abstract: Remote sensing techniques are useful in the monitoring of woody plant species diversity in different environments including in savanna vegetation types. However, the performance of satellite imagery in assessing woody plant species diversity in dry seasons has been understudied. This study aimed to assess the performance of multiple Gray Level Co-occurrence Matrices (GLCM) derived from individual bands of WorldView-2 satellite imagery to quantify woody plant species diversity in a savanna environment during the dry season. Woody plant species were counted in 220 plots (20 m radius) and subsequently converted to a continuous scale of the Shannon species diversity index. The index regressed against the GLCMs using the all-possible-subsets regression approach that builds competing models to choose from. Entropy GLCM yielded the best overall accuracy (adjusted R2: 0.41−0.46; Root Mean Square Error (RMSE): 0.60−0.58) in estimating species diversity. The effect of the number of predicting bands on species diversity estimation was also explored. Accuracy generally increased when three–five bands were used in models but stabilised or gradually decreased as more than five bands were used. Despite the peak accuracies achieved with three–five bands, performances still fared well for models that used fewer bands, showing the relevance of few bands for species diversity estimation. We also assessed the effect of GLCM window size (3×3, 5×5 and 7×7) on species diversity estimation and generally found inconsistent conclusions. These findings demonstrate the capability of GLCMs combined with high spatial resolution imagery in estimating woody plants species diversity in a savanna environment during the dry period. It is important to test the performance of species diversity estimation of similar environmental set-ups using widely available moderate-resolution imagery.
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Remote sensing of woody plant species diversity estimation in a heterogeneous Savanna vegetation ecosystem
- Authors: Fundisi, Emmanuel
- Date: 2021
- Subjects: Woody plants , Savanna plants , Remote sensing
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/483957 , uj:43940
- Description: Abstract: Accurate assessment of savanna woody plant species diversity using remote sensing technologies can help ecologists by providing timely and cost-effective information for sustainable ecosystem management. With the ever-increasing variety of remotely-sensed data becoming available to the public, there is a need to understand the performances of different sensors (optical and structural) in discriminating multiple woody plant species in the savanna environment with morphologically similar features. The overall aim of the present study was to investigate the utility of remote sensing techniques in estimating woody plant species diversity (n = 30) including three different land cover types identified in a complex and localised savanna environment. This was achieved through the following specific objectives: The first objective was to characterise woody plant species diversity during a dry season or period within in a savanna environment, using textural information derived from WorldView- 2 imagery. The second objective was to compare the utility of three multispectral images (WorldView-2, Sentinel-2A and SPOT-6) in classifying woody plant species during a dry season or period. The third objective focussed on the comparison of the classification of savanna woody plant species between wet and dry seasons using Sentinel-2A and SPOT-6 images. The fourth objective assessed the impact of data fusion between Sentinel-1 C band Radio Detection and Ranging (RADAR) and Sentinel-2A multispectral data on discrimination of savanna woody plant species... , Ph.D. (Geography)
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- Authors: Fundisi, Emmanuel
- Date: 2021
- Subjects: Woody plants , Savanna plants , Remote sensing
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/483957 , uj:43940
- Description: Abstract: Accurate assessment of savanna woody plant species diversity using remote sensing technologies can help ecologists by providing timely and cost-effective information for sustainable ecosystem management. With the ever-increasing variety of remotely-sensed data becoming available to the public, there is a need to understand the performances of different sensors (optical and structural) in discriminating multiple woody plant species in the savanna environment with morphologically similar features. The overall aim of the present study was to investigate the utility of remote sensing techniques in estimating woody plant species diversity (n = 30) including three different land cover types identified in a complex and localised savanna environment. This was achieved through the following specific objectives: The first objective was to characterise woody plant species diversity during a dry season or period within in a savanna environment, using textural information derived from WorldView- 2 imagery. The second objective was to compare the utility of three multispectral images (WorldView-2, Sentinel-2A and SPOT-6) in classifying woody plant species during a dry season or period. The third objective focussed on the comparison of the classification of savanna woody plant species between wet and dry seasons using Sentinel-2A and SPOT-6 images. The fourth objective assessed the impact of data fusion between Sentinel-1 C band Radio Detection and Ranging (RADAR) and Sentinel-2A multispectral data on discrimination of savanna woody plant species... , Ph.D. (Geography)
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Survey of community livelihoods and landscape change along the Nzhelele and Levuvhu river catchments in the Limpopo Province, South Africa
- Musakwa, Walter, Wang, Shuai, Wei, Fangli, Malapane, Olgah Lerato, Makamule, Thomas Masala, Mavengahama, Sydney, Hongwei, Zeng, Wu, Bingfang, Zhao, Wenwu, Nesisa, Analisa Nyathi, Mashimbye, Zama Eric, Poona, Nitesh, Chakwizira, James, Gumbo, Trynos, Mokoena, Baleseng, Kaitano, Francis, Fundisi, Emmanuel, Yeni-Letsoko, Vuyiswa
- Authors: Musakwa, Walter , Wang, Shuai , Wei, Fangli , Malapane, Olgah Lerato , Makamule, Thomas Masala , Mavengahama, Sydney , Hongwei, Zeng , Wu, Bingfang , Zhao, Wenwu , Nesisa, Analisa Nyathi , Mashimbye, Zama Eric , Poona, Nitesh , Chakwizira, James , Gumbo, Trynos , Mokoena, Baleseng , Kaitano, Francis , Fundisi, Emmanuel , Yeni-Letsoko, Vuyiswa
- Date: 2020
- Subjects: Landscape change , Livelihoods , Sustainable development
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/415914 , uj:35161 , Citation: Musakwa, W. et al. Survey of community livelihoods and landscape change along the Nzhelele and Levuvhu river catchments in the Limpopo Province, South Africa.
- Description: Abstract: , Landscape change studies have attracted increasing interest because of their importance 29 to land management and sustainable livelihoods of rural communities. However, empirical studies 30 on landscape change and its drivers are often poorly understood, particularly, in small rural 31 communities in developing countries such as South Africa. The present study surveyed local 32 community livelihoods and perceptions of landscape change in the Nzhelele and Levuvhu river 33 catchments in Limpopo Province, South Africa. These areas have experienced land reform and are 34 also characterized by environmental degradation, poverty, inequality and environmental justice 35 concerns among other issues. Land cover maps derived from Landsat satellite imagery were used 36 for purposes of correlating and validating the survey data findings and results. The survey results 37 showed that education levels, working status and marital status have statistically significant effects 38 on community livelihoods (indicated by levels of income, p < 0.05). Maize, fruits and vegetables are 39 the main cultivated crop varieties in the study area, and these crops are mainly used for subsistence 40 to meet household self-consumption requirements..
- Full Text:
- Authors: Musakwa, Walter , Wang, Shuai , Wei, Fangli , Malapane, Olgah Lerato , Makamule, Thomas Masala , Mavengahama, Sydney , Hongwei, Zeng , Wu, Bingfang , Zhao, Wenwu , Nesisa, Analisa Nyathi , Mashimbye, Zama Eric , Poona, Nitesh , Chakwizira, James , Gumbo, Trynos , Mokoena, Baleseng , Kaitano, Francis , Fundisi, Emmanuel , Yeni-Letsoko, Vuyiswa
- Date: 2020
- Subjects: Landscape change , Livelihoods , Sustainable development
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/415914 , uj:35161 , Citation: Musakwa, W. et al. Survey of community livelihoods and landscape change along the Nzhelele and Levuvhu river catchments in the Limpopo Province, South Africa.
- Description: Abstract: , Landscape change studies have attracted increasing interest because of their importance 29 to land management and sustainable livelihoods of rural communities. However, empirical studies 30 on landscape change and its drivers are often poorly understood, particularly, in small rural 31 communities in developing countries such as South Africa. The present study surveyed local 32 community livelihoods and perceptions of landscape change in the Nzhelele and Levuvhu river 33 catchments in Limpopo Province, South Africa. These areas have experienced land reform and are 34 also characterized by environmental degradation, poverty, inequality and environmental justice 35 concerns among other issues. Land cover maps derived from Landsat satellite imagery were used 36 for purposes of correlating and validating the survey data findings and results. The survey results 37 showed that education levels, working status and marital status have statistically significant effects 38 on community livelihoods (indicated by levels of income, p < 0.05). Maize, fruits and vegetables are 39 the main cultivated crop varieties in the study area, and these crops are mainly used for subsistence 40 to meet household self-consumption requirements..
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