Assessing the inter-relationship between vegetation productivity, rainfall, population and land cover over the Bani River Basin in Mali (West Africa) uri icon


  • This research investigated the inter-relationship between vegetation productivity, measured usingthe Normalized Difference Vegetation Index (NDVI), change in rainfall and population density in the context ofperceived greening and degradation trends over the Bani River Basin (BRB). A 30-year (1982-2011), 8-kmgridded rainfall data sets was produced by inverse distance weighted (IDW) interpolation of monthly data from40 meteorological stations contained within the basin. Population data were retrieved from the NationalPopulation Statistic data base for 1987, 1997, and 2009. Rainfall and NDVI time-series trends were computedfor the 30-year period and analysed. The relationship between rainfall and NDVI at pixel level, and NDVI andpopulation densities was analysed using a Pearson correlation. Land Use and Land Cover (LULC) conversionrates were computed for the same period using multi-temporal 30-meter Landsat imagery; ground surveys forselected areas within the basin were used for further cross-verification. The computed NDVI trends revealedthat, vegetation 'greening' trends are mostly associated with areas where natural vegetation is still wellrepresented. Concurrent with increases in rainfall over the period analysed, this finding supports the hypothesisthat re-greening observed in that area is the result of multi-decadal fluctuations in climate, rather than improvedland management

publication date

  • 2015