Résumé:
Mostaganem's western coastal zone (study area) is characterized by an urban concentration and a
variety of economic activities, including agriculture, industry, transport (land and sea), fishing and
green and seaside tourism. The geomatics approach adopted involved the use of GIS and remote
sensing tools to diagnose environments (physical, biotic and abiotic) and map land use. GIS
processing methods applied using ArcGis software (version 10.8) to eight (8) 1:25,000 topographic
maps (1989) and a 30m DEM (2000) were used to delimit the area of interest and characterize its
relief. The remote sensing methods involved using ArcGis software to generate six (6) vegetation
index images from six (6) Sentinel-2 images acquired between January and August 2024. Other
images such as Bing Microsoft and images archived in Google earth Pro. were used to refine the
interpretation of the satellite images. Analysis of the results shows that the western coastal zone
(study area) is administratively delimited by four (4) coastal communes (Fornaka, Stidia,
Mazaghrane and Mostaganem). It covers a total area of 18,400 ha with a coastline of 48.5 km. Its
relief is gently sloping. The land-use map shows that vegetation surfaces (agriculture, forest and
halophilic vegetation) are more important than mineral surfaces (bare soil, urban areas and
associated facilities). At the end of January 2024, planted areas occupied a total surface area of
15,129 ha (82% of the zone's total), of which 23% was forest. Between the months of January and
August 2024 (8 months), the vegetated area decreased by 8,810 ha (48% of the total area) due to the
seasonal cycle of crops. Mineral surfaces have doubled (2) more than plant surfaces, due to the
increase in bare soil surfaces after seasonal harvesting. This loss of vegetation increases the risk of
erosion, reduces oxygenation of the environment and reduces carbon sequestration.
