Evolution Du Couvert Végétal Naturel Au Niveau Des Massifs Forestiers De Mallalyine Et Taghramt (Rif Occidental Du Maroc)

This work presents the results of a cartographic study of the spatiotemporal evolution of vegetation cover in the forest areas of Mallalyine and Taghramt in the western Rif. It is based on a field survey and the photointerpretation of aerial photographs taken in 1986 and Google Earth images from 2013 (a period of twenty-seven years). Our study reports on the current state of degradation of the vegetation cover in the forests of Mallalyine and Taghramt. We have produced two land use maps showing how high and low formations as well as scrub have regressed by 62, 70 and 49 percent, respectively, between 1986 and 2013, while non-forested land and reforestation increased respectively by 26.3 and 1.53 percent relative to the area covered in 1986. The main factors contributing to the decline of vegetation cover are: deforestation (35 offenses registered every year with a degraded area of about 15 ha / year), clearing (27 offenses per year with an European Scientific Journal August 2018 edition Vol.14, No.24 ISSN: 1857 – 7881 (Print) e - ISSN 1857- 7431 20 affected area of about 20 ha / year), overgrazing (10 offenses of illegal grazing per year with a degraded area of about 12 ha / year), forest fires (4 to 5 fires per year with a degraded area of about 50 ha / year). In addition to these factors, we find increasing water scarcity

Aridity gradients shape intraspecific variability of morphological traits in native Ceratonia siliqua L. of Morocco

The carob tree (Ceratonia siliqua L.) is a significant fruit tree in the Mediterranean region with cultural, biological, and ecological importance. Despite its importance, intraspecific trait variability (ITV) in carob trees has been largely overlooked in previous studies. Understanding ITV and its relationship with environmental conditions is crucial for conservation and breeding programs. In this study, we investigated the variability of carob pod and seed-related traits across different ecological scales in 25 studied populations in Morocco. Significant differences in morphological traits were observed between carob populations at various ecological levels, and pod-related traits exhibited greater variability than seed traits. Correlation analysis revealed strong associations between carob morphological traits and environmental conditions, with altitude and aridity index playing an influential role. The aridity gradient was strongly related to changes in pod size, seed number, and size, as well as seed yield. Our findings highlight an important ITV reaching 45% at the intra-population level, 36.5% at the inter-geographic level, and 30% at the inter-population level. Overall, this study contributes valuable insights into the ecology and adaptation of carob trees, emphasizing the importance of considering intraspecific variability when studying this remarkable species. This knowledge is critical for addressing the challenges posed by climate change and human activities on the long-term survival and ecological functioning of carob populations

Enhanced FPGA-Based Controller for Three Phase Shunt Active Power Filter

In this paper, a three-phase shunt active power filter (SAPF) controller with a fully digital implementation is presented. The main goal of this contribution is to implement a digital direct power control (DDPC) algorithm without phase-locked-loop (PLL) for SAPF. This algorithm is intended for power quality improvement and current harmonic elimination. The controller introduced in this paper is cost-effective, has a fast-dynamic response, and has a simple hardware implementation. In order to comply with the above specifications, a dedicated controller has been conceived and fully implemented within a field-programmable gate array (FPGA) device. This FPGA-based controller integrates the whole signal-processing functions needed to drive the SAPF, as well as an original method for sector identification. The intended controller provides the desired power references to select the optimal switching sequences. The switching orders follow the grid reference to drive the voltage source inverter (VSI), so the SAPF achieves good performances while ensuring balanced overall supply currents, unity power factor, and reduced harmonic load currents. The proposed digital implementation achieves a valuable compromise between fast dynamic response, minimum execution time, and reduced FPGA resources, through a simple hardware design implementation. The entire system is developed and simulated using VHDL and VHDL-AMS languages

Pollen Variability of <i>Alnus glutinosa</i> (L.) Gaerth. (Betulaceae) from Southern Range Edge Populations in Northern Morocco

Moroccan populations of Alnus glutinosa (L.) Gaerth. (Betulaceae) are found at the southern limit of the species’ range and are represented by tetraploid cytotypes with no available pollen data. The objective of this study was to assess the morphological and morphometric variability of the pollen, specifically focusing on pollen diameters and the number of apertures. To achieve this, we sampled 11 populations that are representative of the Moroccan distribution area of this species. We employed a hierarchical sampling design (11 populations, 10 trees per population, and from 30 to 300 pollen grains per tree, depending on the character measured) to examine different levels of variability: interpopulation, intrapopulation, and intraindividual. The results demonstrate that there is no discernible difference in the morphology or size of the pollen among the Moroccan tetraploid populations. However, we observed a high degree of intraspecific variability in pollen morphometric traits, but most of this variability is associated with the intraindividual level

Germination and seed traits in common alder ( Alnus spp.): the potential contribution of rear‐edge populations to ecological restoration success

International audienceThe degradation of riparian ecosystems occurring throughout the past decades has motivated efforts aimed at the restoration of these ecosystems. The success of active revegetation approaches to restoration requires appropriate selection of reproductive material, which in turn requires knowledge of seed traits and germination. Alnus glutinosa (L.) Gaertn. (common alder) is a key riparian tree widely used in restoration projects, and has recently been classified as comprising three species: A. glutinosa; A. lusitanica Vit, Douda, & Mandak; and A. rohlenae Vit, Douda, & Mandak. To help guide restoration species selection, we assessed differences among populations of these species by (1) investigating seed weight, morphology, and germination success from a large population set and (2) modeling germination success in each species in relation to morphological traits and environmental conditions. Seeds were collected from 12 populations encompassing the latitudinal extremes of the species complex, and were then characterized and germinated. Ploidy levels and species were distinguished using cytometric analysis. Site-level climatic data and seed morphology data were used to model germination success for each species. All seed traits differed between populations and one morphological-trait (seed weight-to-area ratio) differed significantly between the three species. Germination modeling showed that the southwestern species, A. lusitanica, responded positively to high temperature extremes, suggesting tolerance to the climate changes projected for southern Europe. Populations of A. lusitanica located at the latitudinal rear edge of common alder's distribution appear to show establishment-facilitating adaptations, and therefore may contribute to ecological restoration efforts under a range of environmental conditions