Étude de l’évolution du ravinement dans les jessour du Sud Tunisien grâce aux images aériennes

Abstract

In southern Tunisia, agricultural land has been subject to significant anthropogenic pressures since the early 20th century, which have contributed to significant changes in land use. The region's strong demographic growth has led to socio-spatial changes (sedentarisation, the descent of mountain populations down to the foothills and the Djeffara plain, the development of agriculture in the jessour (water and soil conservation works that block the gullies dug in the loess) at the expense of the rangelands. The current landscapes of southern Tunisia, from the Matmata region to the surroundings of Tataouine, now display signs of a rural exodus that is reflected in the abandonment of the jessour. This exodus has significant landscape and environmental impacts that can be measured through the use of diachronic vertical imagery (aerial photographs, satellite images). It can be observed that from the 1950s onwards, jessour developed strongly in the ravines, in line with demographics. The rural exodus that appeared in the 1970s led to the concentration of populations in the new towns, which did not prevent water and soil conservation works from continuing to be used and maintained. While some areas, particularly in the southern part of the study area, are still seeing the appearance of new jessour, most of them are abandoned and subjected to regressive erosion due to the suffocation that rapidly destroys them.

Keywords

• landscape
• agriculture
• aerial photography
• satellite imagery
• Matmata