Modeling and assessing driving factors of the spatial and temporal dynamics of the sand dunes in the district of Errachidia, Morocco

The desertification affects more than 250,000 ha in the district of Errachidia (Morocco) and results in the expansion of desert landscapes such as the regs, hamadas, and dunes. The latter is a big concern in the district since it is the source of siltation, which threatens dwellings, cultivated lands, and water bodies. To better understand the phenomena, we analyzed the spatial and temporal dynamics of sand dunes until 2069 by applying the seasonal autoregressive integrated moving average (SARIMA) model on a time series of sand dune areas calculated annually from 1987 to 2019 by computing the sand cover index (SCI) on Landsat satellite images. The results indicated that the area of sand dunes would increase by 1.7%/year between 2019 and 2069 in the district of Errachidia. Furthermore, we evaluated the influence of different natural and human factors such as temperature, precipitation, wind, vegetation, and population growth on sand dune dynamics using Spearman’s correlation test. We deduced from the test results that the factors influencing the sand dune expansion do not act individually. Indeed, temperature and precipitation act significantly on wind and vegetation respectively, to influence the dynamics of sand dune in hyper-arid areas where the soil is bare or poorly covered with vegetation, where precipitation is low and where temperature is high. Moreover, Spearman’s correlation test revealed that population growth is not significantly correlated with the dynamics of sand dunes. However, well-planned, conducted, and regulated human practices can help reduce silting up in desert areas.