Spatio-temporal analysis of North African forest cover dynamics using time series of vegetation indices – case of the Maamora forest (Morocco)

North African forest areas play several roles and functions and represent a heritage of great economic and ecological importance. As a result of global changes, that act independently or synergistically, these areas are currently undergoing a pronounced degradation and their productivity is decreasing due to several factors. This work aims to characterize spatio-temporal dynamics of vegetation within the Maamora forest. This forest is considered as the most extensive cork oak woodland in the world and is divided, from west to east, into five cantons A, B, C, D and E. The data, extracted between 2000–2021 from MODIS NDVI/EVI images of 250 m, were analyzed using statistical parameters with the Pettitt homogeneity and the Mann-Kendall trend tests, with their seasonal and spatial components, in order to better consider the vegetation distribution of this forest. Results show a clear temporal and spatial (inter-canton) variability of vegetation intensity, unrelated to the continental gradient. In fact, recorded mean values in cantons C and E are significantly higher than those of cantons B and D respectively. This is confirmed by both regressive and progressive trends, which were identified respectively from the months of March 2012 and October 2008, in the data series of cantons B and E successively. Spatially, the regressive dynamic remains generalized and affects more than 26.7% of the Maamora’s total area with extreme rates (46.1% and 14.0%) recorded respectively by the two aforementioned cantons. Similarly, all the stand types in canton B show the highest regressive rates, especially the cork oak regeneration strata (75.4%) and the bare lands (86.1%), which may explain the positive tendencies identified by the related series during the fall season. However, the cantons C and E record the lowest rates, respectively, for natural stands of cork oak and artificial plantations. These results highlight also the absence of a causal relationship between the contrasting vegetation dynamics of the Maamora and the climatic conditions, expressed here by the continental gradient. However, they do highlight the effects of other factors, particularly those of a technical nature

Assessing the impact of vegetation cover dynamics on water erosion using PAP/RAC method and remote sensing in the Kharouba watershed (Central Plateau, Morocco)

Le présent travail a pour objectif d’évaluer l’impact de la dynamique du couvert végétal forestier sur l’érosion hydrique au niveau du bassin versant de Kharouba dans le Plateau central marocain. La méthodologie adoptée repose sur l’analyse diachronique du couvert végétal entre 1986 et 2008 en se basant sur le traitement des photographies aériennes datées de 1986 et une image SPOT de 2,5 m de résolution datée de 2008. Les cartes du couvert végétal obtenues ont été utilisées pour l’élaboration des cartes des états érosifs de 1986 et 2008, en se basant sur la méthodologie proposée par PAP/CAR. Les principaux résultats de cette étude montrent qu’il y a une évolution régressive du couvert végétal. Cette régression a contribué à l’augmentation du risque de l’érosion hydrique à l’échelle du bassin versant. L’étendue des zones vulnérables à l’érosion hydrique est passée de 39 % de la surface du bassin versant en 1986 à 45% en 2008. Mots clés: Couvert végétal, Erosion hydrique, Bassin versant, méthodologie PAP/CAR, Plateau Central, MarocThis work aims to assess the impact of the vegetation cover on water erosion in Kharouba watershed in Morocco Central Plateau. The methodology is based on diachronic analysis of land cover between 1986 and 2008, using 1986 aerial photographs and a 2.5 m resolution SPOT satellite image from 2008. The land cover maps obtained were used to develop erosion status maps for 1986 and 2008, using PAP/RAC methodology. The results achieved highlight the regressive evolution of vegetation cover between 1986 and 2008. This decline contributed to the increase of water erosion risk in Kharouba watershed, which causes the expansion of vulnerable areas to water erosion from 39% of the basin surface in 1986 to 45% in 2008.  Keywords: Vegetation cover, Water Erosion, Watershed, PAP/RAC, Central Plateau, Morocc

Etude chimique et biologique des huiles essentielles de Juniperus phoenicea ssp. lycia et Juniperus phoenicea ssp. turbinata du Maroc

Chemical and biological study of essential oils of Moroccan Juniperus phoenicea ssp. lycia and Juniperus phoenicea ssp. turbinata. The composition of the essential oils of the branches and berries of Juniperus phoenicea (Cupressaceae), J. phoenicea ssp. lycia (plain) and J. phoenicea ssp. turbinata (mountain), obtained by hydrodistillation, collected from Morocco, was analyzed by GC and GC/MS. The yields of essential oils were varying in function of the subspecies and of the part of the plant studied. The essential oils of these tree species are largely dominated by α-pinene and may be an important source of this component of a great interest on the international market. The effectiveness of essential oils from branches of the subspecies lycia against fungi decay wood has also been emphasized

Composition chimique et activité antimicrobienne des huiles essentielles de Thymus algeriensis Boiss. & Reut. et Thymus ciliatus (Desf.) Benth. du Maroc

Chemical composition and antimicrobial activity of the Thymus algeriensis Boiss. & Reut. and Thymus ciliatus (Desf.) Benth. essential oils of Morocco. The aim of this work is to study the chemical composition and antibacterial and antifungal activity of essential oils of Thymus algeriensis Boiss. & Reut. and Thymus ciliatus (Desf.) Benth. of Morocco against seven microorganisms. The essential oils of T. ciliatus are characterized by the presence of thymol (44.2%), β-E-ocimene (25.8%) and α-terpinene (12.3%) as principal chemical components. The essential oils of T. algeriensis are formed mainly by camphor (27.7%) and α-pinene (20.5%). The oil of T. ciliatus showed a strong antibacterial and antifungal activity against all tested bacteria and fungi. This bioactivity is due mainly to the richness of this essential oil in thymol known for its effectiveness against the microbial agents

Activité antifongique des huiles essentielles de Thymus bleicherianus Pomel et Thymus capitatus (L.) Hoffm. & Link contre les champignons de pourriture du bois d'oeuvre

Antifungal activity of the Thymus bleicherianus Pomel and Thymus capitatus (L.) Hoffm. & Link essential oils againstwood-decay fungi. Essential oils and their constituents have a long history of applications as antimicrobial agents, but theiruse as wood preservatives has rarely been reported. This study deals with the antifungal activity of two medicinal and aromaticplants essential oils of the Moroccan flora against four wood-decay fungi, in order to find new bioactive natural products. Thechemical composition of essential oils extracted by hydrodistillation from the aerial parts of Thymus bleicherianus Pomel andThymus capitatus (L.) Hoffm. & Link was analyzed by GC and GC-MS. The major components of T. bleicherianus oil wereα-terpinene (42.2%) and thymol (23.9%). Carvacrol (70.92%) was the predominant constituent in the essence of T. capitatus.Minimal inhibitory concentrations of the essential oils added to malt agar medium in defined concentrations were determinedby a screening test with the agar dilution method. The oils, object of the survey, showed a strong antifungal activity againstall tested fungi