Using of Landsat images for land use changes detection in the ecosystem : a case study of the Senegal river delta.

Abstract

Land use changes study is an essential step for the monitoring and assessment of ecosystems. In Senegal River delta, ecosystem has experienced significant changes from 1970 to nowadays. Several natural and anthropic factors are at the origin of these modifications. The aim of this paper is to reconstruct the history of land use in the Senegal River delta and detect these changes. For this, Landsat images acquired in 1972 (MSS), 1984 and 1988 (TM), 1999 and 2006 (ETM) and 2014 (OLI) are used to make the diachronic study. We have first conducted a pretreatment of the image (relating to the geometrical and radiometric correction and the equalization of the histograms), calculated of pseudo ACP bands and NDVI, classified and validated the images and finally detected changes by individual classification method. The results obtained, broadly show significant changes in terms of areas gain for the land plants (231%), growing areas (95%) and aquatic vegetation (75%). This dynamic is at the expense of saline lands, dune surfaces and the water areas. Interesting perspectives for authorities and decision makers in precise management of the ecosystem in the Senegal River delta are offered as well.