Secondary Succession and Dynamics of Wetland and Riparian Vegetation of Asaba-Onitsha River Niger Corridor Using Geospatial Techniques
- Paper number
IAC-14,B5,1,8,x20395
- Author
Mr. Okeke Ugo Henry, COPIN/ASTAL-NASRDA OAU CAMPUS, Ile-Ife, Nigeria
- Coauthor
Prof. Mohammed Seidu O., National Space Research and Development Agency, Aduja, Nigeria
- Coauthor
Mr. Eguaroje O. Ezekiel, COPIN-NASRDA OAU Campus, Ile-Ife, Nigeria
- Year
2014
- Abstract
Wetlands and their riparian vegetation are natural ecological resources that are marked invaluable all over the world and vital for sustainable environment and the general ecosystem. This work studied the dynamics and alteration of wetlands/riparian vegetation as a base for wetlands management and sustainable green environment around the Asaba-Onitsha River Niger corridor. The area extent of wetlands was mapped, the rate of change was determined and the wetland vegetation quality using NDVI was ascertained. The data sets used include: Landsat TM 1987, Landsat ETM 2001, and 2004 satellite images, while other secondary data includes: topographic, soil, geology maps and DEM covering the study area. The data from ground-truthing combined with visual image interpretation were used for supervised classification of the imageries with an average kappa coefficient and overall accuracy of 0.94 and 95.7% respectively. Six Landuse/ Land cover class were identified; these were; built up, wetland/riparian vegetation area, upland vegetation, sand deposit, water body, and bare surfaces. The different data sets were overlaid and interpolated to delineate the wetland area while decision tree algorithm was used to determine the NDVI value of the riparian vegetation area over the period of study (1987-2012). The result showed significant changes in the wetland area in relation to other landuse. The wetland area decreased from 326.625km2 in 1987 to 128.6905km2 in 2002 with continual negative magnitude of change and annual frequency of change of -197.9348km2 and -7.917km2 respectively which means that an average of 8km2 of wetland area are altered annually. The NDVI value of the riparian vegetation that ranges from +0.27 to -0.09 shows that the vegetation quality is at the decrease, indicating a tempered ecosystem and rapid secondary succession which are attributed to factors majorly anthropogenic. The study recommended that environmental regulation, education and wetland conservation should be given top priority.
- Abstract document
- Manuscript document
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