Assessing Long-Term Trends In Vegetation Productivity Change Over the Bani River Basin in Mali (West Africa)

Souleymane S. Traore, Tobias Landmann, Eric K. Forkuo, Pierre C.S. Traore, 'Assessing Long-Term Trends In Vegetation Productivity Change Over the Bani River Basin in Mali (West Africa)', Journal of Geography and Earth Sciences, vol. 2(2), American Research Institute for Policy Development, 2014

Using time series of Normalized Difference Vegetation Index (NDVI) and rainfalldata, we investigated historical vegetation productivity trends from 1982 to 2011over the Bani River Basin in Mali. Statistical agreements between long-term trendsin vegetation productivty, corresponding rainfall and rate of land cover change fromLandsat time-series imagery was used to discern climate versus human-inducedvegetation cover change. Spearman correlation was used to investigate therelationship between metrics of vegetation, rainfall trends and land cover changecategories. The results show there is a positive correlation between increases inrainfall and some land cover classes, while some classes such as settlements werenegatively correlated with vegetation productivity trends. Croplands and NaturalVegetation were positively correlated (r=0.89) with rainfall while settlements have anegative correlation with NDVI time series trend (r=-057). Despite the fact thatrainfall is the major determinant of vegetation cover dynamics in the study area, itappears that other human-induced factors such as urbanization have negativelyinfluenced the change in vegetation cover in the study area. The results show that acombined analysis of NDVI, rainfall and spatially explicit land cover changeprovides a comprehensive insight into the drivers of vegetation cover change insemi-arid Africa