Contribution to the evaluation of the biomass of medicinal and aromatic plants in Mo-rocco: Case of Globularia alypum

Morocco is distinguished by the richness of its flora, including medicinal and aromatic plants (MAPs) which play an important role, particularly in rural populations. Due to pressures often associated with overexploitation, monitoring of MAPs is essential to ensure their sustainability. This study looked to explore the status of Globularia alypum in the Amsittene site of biological and ecological interest (SBEI) in Morocco. A destructive technique was adopted to quantify biomass and productivity of G. alypum at six sites with different ecological characteristics in the Amsisttene SBEI. Linear regression was used to model G. alypum biomass as a function of the normalized difference vegetation index (NDVI). Tree cover had the greatest influence on G. alypum dynamics, showing a significant effect on shrub height, leaf productivity, and total productivity, as did the cutting method, with the highest biomass estimated based on pair matching of similar individuals. NDVI was found to be an adequate indicator of G. alypum biomass, given their high correlation (0.84) with the selected model having an R2 of 0.7. The yield of extracted essential oils ranged from 3.19 to 113.43 L, from which 10 chemical compounds were identified, with ethylvanillin being the most prominent

Impact of climate change on potential distribution of Quercus suber in the conditions of North Africa

Climate change, which is expected to continue in the future, is increasingly becoming a major concern affecting many components of the biodiversity and human society. Understanding its impacts on forest ecosystems is essential for undertaking long-term management and conservation strategies. This study was focused on modeling the potential distribution of Quercus suber in the Maamora Forest, the world’s largest lowland cork oak forest, under actual and future climate conditions and identifying the environmental factors associated with this distribution. Maximum Entropy approach was used to train a Species Distribution Model and future predictions were based on different greenhouse gas emission scenarios (Representative Concentration Pathway RCPs). The results showed that the trained model was highly reliable and reflected the actual and future distributions of Maamora’s cork oak. It showed that the precipitation of the coldest and wettest quarter and the annual temperature range are the environmental factors that provide the most useful information for Q. suber distribution in the study area. The computed results of cork oak’s habitat suitability showed that predicted suitable areas are site-specific and seem to be highly dependent on climate change. The predicted changes are significant and expected to vary (decline of habitat suitability) in the future under the different emissions pathways. It indicates that climate change may reduce the suitable area for Q. suber under all the climate scenarios and the severity of projected impacts is closely linked to the magnitude of the climate change. The percent variation in habitat suitability indicates negative values for all the scenarios, ranging –23% to –100%. These regressions are projected to be more important under pessimist scenario RCP8.5. Given these results, we recommend including the future climate scenarios in the existing management strategies and highlight the usefulness of the produced predictive suitability maps under actual and future climate for the protection of this sensitive forest and its key species – cork oak, as well as for other forest species

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

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

Influence of processing conditions on nanoindentation properties of spark plasma sintered ptfe

The Spark Plasma Sintering (SPS) is considered as fast sintering route using self-heating action from inside the powder similar to microwave sintering and self-propagating high temperature. High sintering rate, low temperature processing, ease of operation and accurate control of sintering energy are the major advantages of this non-melting technique with regard to classical methods. The aim of this investigation is to take benefit from the advantages offered by the SPS process in order to sinter the polytetrafluoroethylene (PTFE) polymer materials from PTFE powder particles. The effect of the process’s parameters, namely the sintering temperature and heating rate, on the nanoindentation deformation is explored at room temperature. Empirical data on depth-dependent hardness are confronted to some theoretical models with a special focus on the apparent surface stress changes with the indentation depth. Furthermore, the obtained results are compared to the macro-behavior deduced from tensile and bending properties in order to assess the change in both surface and bulk deformations of the SPSed samples and according to the processing parameters

Nanoindentation hardness and macroscopic mechanical behaviors in filled elastomeric nanocomposites

Carbon black (CB) filled semi-crystalline ethylene butyl acrylate (EBA) copolymer networks are investigated to probe for the CB particles dependence of the deformation behavior from nano-to micrometers length scales of samples which are submitted to nanoindentation characterization. With respect to this purpose, the phenomenology for hardness (H) response in these materials indicates a typical increase of the hardness by decreasing the indentation depth (h) similar to the observed behavior in elastomeric materials. This behavior can be related to the change of the mesostructure, formed by the heterogeneous three-dimensional interconnected network of polymer and of aggregates of CB particles. Furthermore, The CB amount is found to increase the resistance of composite under the action of a mechanical stress. The H-h curves were then compared to some analytical models and correlated to a tensile macroscopic behavior in order to highlight the involved deformation mechanisms with length scale. A complementary set of characterizations such as profilometry and atomic force microscopy probes were also employed to best understand of those mechanisms

Nanoindentation hardness and macroscopic mechanical behaviors in filled elastomeric nanocomposites

Carbon black (CB) filled semi-crystalline ethylene butyl acrylate (EBA) copolymer networks are investigated to probe for the CB particles dependence of the deformation behavior from nano-to micrometers length scales of samples which are submitted to nanoindentation characterization. With respect to this purpose, the phenomenology for hardness (H) response in these materials indicates a typical increase of the hardness by decreasing the indentation depth (h) similar to the observed behavior in elastomeric materials. This behavior can be related to the change of the mesostructure, formed by the heterogeneous three-dimensional interconnected network of polymer and of aggregates of CB particles. Furthermore, The CB amount is found to increase the resistance of composite under the action of a mechanical stress. The H-h curves were then compared to some analytical models and correlated to a tensile macroscopic behavior in order to highlight the involved deformation mechanisms with length scale. A complementary set of characterizations such as profilometry and atomic force microscopy probes were also employed to best understand of those mechanisms

Microbial biotransformation of beclomethasone dipropionate by Aspergillus niger

In the present research, the steroidal anti-asthmatic drug beclomethasone dipropionate was subjected to microbial biotransformation by Aspergillus niger. Beclomethasone dipropionate was transformed into various metabolites first time from microbial transformation. New drug metabolites produced can act as new potential drug molecules and can replace the old drugs in terms of safety, efficacy, and least resistance. They were purified by preparative thin layer chromatography technique, and their structures were elucidated using modern spectroscopic techniques, such as 13C NMR, 1H NMR, HMQC, HMQC, COSY, and NOESY, and mass spectrometry, such as EI-MS. Four metabolites were purified: (i) beclomethasone 17-monopropionate, (ii) beclomethasone 21-monopropionate, (iii) beclomethasone, and (iv) 9beta,11beta-epoxy-17,21-dihydroxy-16beta-methylpregna-1,4-diene-3,20-dione 21-propionate