Spatio-temporal dynamics of vegetation cover in North-West Algeria using remote sensing data

Land cover change is the result of complex interactions between social and environmental systems which change over time. While climatic and biophysics phenomena were for a long time the principal factor of land transformations, human activities are today the origin of the major part of land transformation which affects natural ecosystems.

Quantification of natural and anthropogenic impacts on vegetation cover is often hampered by logistical issues, including (1) the difficulty of systematically monitoring the effects over large areas and (2) the lack of comparison sites needed to evaluate the effect of the factors.

The effective procedure for measuring the degree of environmental change due to natural factors and human activities is the multitemporal study of vegetation cover. For this purpose, the aim of this work is the analysis of the evolution of land cover using remote sensing techniques, in order to better understand the respective role of natural and anthropogenic factors controlling this evolution.

A spatio-temporal land cover dynamics study on a regional scale in Oranie, using Landsat data for two periods (1984–2000) and (2000–2011) was conducted. The images of the vegetation index were classified into three classes based on Normalized Difference Vegetation Index (NDVI) values and analysed using image difference approach.

The result shows that the vegetation cover was changed. An intensive regression of the woody vegetation and forest land resulted in -22.5% of the area being lost between 1984 and 2000, 1,271 km² was converted into scrub formations and 306 km² into bare soil. On the other hand, this class increased by around 45% between 2000 and 2011, these evolutions resulting from the development of scrub groups with an area of 1,875.7 km².