- Title
- Multi-temporal assessment of spatial changes in vegetation distribution in the Swartkops estuary, Port Elizabeth, Eastern Cape, South Africa
- Creator
- Atyosi, Yonwaba
- Subject
- Climatic changes -- South Africa -- Eastern Cape Environmental impact analysis Estuaries -- South Africa -- Eastern Cape
- Date Issued
- 2017
- Date
- 2017
- Type
- Thesis
- Type
- Masters
- Type
- MSc
- Identifier
- http://hdl.handle.net/10353/13762
- Identifier
- vital:39710
- Description
- Over the last decade, image classification has been widely used as a change detection method and provides detailed information for detecting and monitoring changes in land use and land cover (LULC). The main objective of this study was to reconstruct long-term changes in the spatial distribution of different vegetation types in the Swartkops Estuary from 1983 to 2013. The Swartkops Estuary is ecologically important for its wide range of vegetation types that are habitat to estuarine and riverine organisms. Four Landsat images for the years 1984 (Thematic Mapper), 1993 (Thematic Mapper), 2003(Enhanced Thematic Mapper +) and 2013 (Operational Land Imager) were used with the aid of aerial photographs that were used as an ancillary data source. The research methodology comprised of supervised classification, classification accuracy assessment and image differencing. Supervised classification was performed and results of the image classification process for the four time periods were compared to derive information on changes that occurred over the 29-year study period. Images were classified into the following classes: Estuarine water, Salt works, Zostera capensis, Spartina maritima, Terrestrial vegetation, Salt marsh, Swartkops thicket, Built-up areas, Bare areas, and Beach sand, using the Maximum likelihood classifier on Erdas IMAGINE 2014 Software. The significance of the image classification was tested using linear trend regression analysis. Image differencing was performed using 1984 and 2013 Landsat images to reconstruct overall changes in vegetation distribution of the Swartkops Estuary. Results of this investigation revealed significant changes in all land cover types, 24 ha increase from 1984 to 2013 in Zostera capensis as well as Spartina maritima, salt marshes increased by 14 ha between 1984 and 2013, terrestrial vegetation declined by 18 ha between 1984 and 2013. There was a stable increase in estuarine water from 1984 to 2013 by a total area of 29 ha. Water increased by 14 ha between 1984 and 1993, 11 ha increase between 1993 and 2003. However, there was a decline in estuarine water in the period between 2003 and 2013.This decline is associated with the increase in submerged macrophytes like Zostera capensis which utilise open water habitat. The dominant salt marsh species Limonium peregrinum, Sarcoconia pillansii and Spartina maritima occurred in the intertidal, supratidal and floodplain areas where the water table was the shallowest, with the soil moisture being the highest. These results indicate that Remote Sensing and GIS can be effectively used to detect and monitor changes in estuarine biodiversity and habitat in South Africa.
- Format
- 104 leaves
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
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UFH Department of GIS & Remote Sensing
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details Download | SOURCE1 | MSc (GIS & Remote Sensing) ATYOSI.pdf | 2 MB | Adobe Acrobat PDF | View Details Download |