One of the most important indicators for land degradation is the progressive salinization of soils. This work, conducted at the Dawling National Park (southern Mauritania), assess the effects of salinity on soil quality. Analyzes of spatial variation in salinity were performed using interpolation and spatial analysis (GIS) methods. Thus, maps of electrical conductivity have been developed using several methods of interpolation and spatial analysis: Inverse Weighting (IDW), Local Polynomial Interpolation (LPI), Radial Base Function (RBF) and Ordinary Kriging (OK). The obtained results showed that the best estimator is IDW method, which provides a good ability to predict electrical conductivity, with a mean squared error (RMSE) of 0.34 mS/cm and a correlation coefficient (R) of 0.99.

The aim of this paper is to evaluate the impact of forest cover dynamics on the erosion at Kharouba watershed in the Moroccan Central Plateau. Our methodology is based on the diachronic analysis of the land cover between 1986 and 2016, using treatments of aerial photographs from 1986 and a Google Earth satellite imagery at a high resolution from 2016. The land cover maps obtained were used to establish erosion status maps between 1986 and 2016, based on methodology PAP/RAC. Our study highlights the regressive evolution of vegetation cover. This decline has stressed the increased water erosion risk in Kharouba watershed causing the spread of the areas that are vulnerable to water erosion from 36 % in 1986 up to 41 % in 2016.

The main objective of this study is to quantify the floral richness and diversity of Tetraclinis ecosystem in the Moroccan Central Plateau. The approach was based on over 300 floristic surveys covering the different parts of the Moroccan Central Plateau forests. It also entails the analysis and processing of data from studies in the region. The results indicate that there are 233 taxa belonging to 56 families. Keywords: Floral richness, Tetraclinis ecosystem, Moroccan Central Plateau IntroductionDue to its typical and geographical position between the Atlantic Ocean to the west and the Mediterranean Sea to the north, Morocco is characterized by high vascular plant diversity with approximately 4200 species and subspecies belonging to 135 families and 940 genera (Benabid, 2000). The endemic flora includes 951 species and subspecies, representing 21 % of the Moroccan vascular plants. The richest floristic regions for endemic species are located at the top of high mountains.By its geographical position, its varied topography, geology, ecoregion and climate, the Central Plateau of Morocco includes a large area of forest ecosystems with an important floristic diversity. However, this flora richness is still not well known and botanical studies within the zone still remains limited.

The current study aims to quantify and evaluate the Tetraclinis stands (Tetraclinis articulata (Vahl.) Masters) richness and floristic diversity at Kharouba Site of Biological and Ecological Interest (SBEI). The 150 floristic surveys conducted in the site allowed us to inventory 143 species distinguished with rare taxa majority that are distributed over 54 families and 123 genera. This reduced number of taxa reflects the alarming biodiversity deterioration of the SBEI. The study also enabled us to define the biological spectrum of the study area that is characterized by a significant abundance of Therophytes.

A better knowledge of the land use of an environment is based on the establishment and comparison of various spatio-temporal situations of the different components of this space. This work is part of a research on the dynamics of the Maamora forest. It aims to show the contribution of the use of geomatics tools in the evaluation of dynamics of forest cover and therefore the evaluation of the impact of global changes and previous forest management methods. The approach followed for the assessment of forest cover in 1984, 1994, 2004, 2014 and 2019, was based on satellite images of Landsat 5 and Landsat 8, with a spatial resolution of 30 m. The classification supervised by the “Support Vector Machine” (SVM) algorithm made it possible to develop forest cover maps for the dates selected and subsequently to evaluate the changes. The classification evaluation showed a Kappa coefficient over 87% and an overall accuracy over 90% for all the selected dates. The results showed a great dynamic of the forest cover between 1984 and 2019 with two significant periods. The first one is 1984-1994 when areas of cork oak and acacia fell respectively by 20% and 39% in favor of other introduced forest species, mainly eucalyptus and pines, which increased respectively by 28% and 74%. For the second period 1994-2019, there was a reversal trend of regression of cork oak’s area towards an increase of 11%, while the area of eucalyptus plantations was generally stabilized and that of pines and acacia stands fell by 37% and 33% respectively. These results make it possible to provide decision-makers with tools for the future management of the space.