Study of the Dynamics of Vegetation Through the Use of Vegetation Indices in the Region of Djelfa, Algeria

The objective of this study is to propose an approach for monitoring the spatio-temporal evolution of land use in semi-arid steppe zones through the example of the Djelfa zone in Algeria over a period of 36 years. (1986-2021) and systematic sampling over 5 years (8 samples), as well as observation of the impact of climate and human activities on the natural plant cover.Three vegetation indices: NDVI, EVI, and MSAVI , were first calculated in the spring period, then aggregated by two methods: the Median, and the greenest pixel, to determine the composite mosaic images and the index best suited to describing the vegetation of the area.The results obtained showed that the MSAVI aggregated by the greenest pixel method presented the vegetation better than EVI and NDVI; And that there is a considerable degradation of the forest cover caused mainly by agriculture which increased; A degradation in steppe rangeland is also noted due to climatic degradation caused by a reduction in precipitation, and on the other hand the decline in steppe surface area, and overgrazing.