No abstract

Along with being a dynamic process that affects large areas, desertification is also one of the most serious problems in many countries. The effects of this phenomenon threaten the sustainability of natural resources, namely water resources, agricultural production and major basic infrastructure, specifically roads and habitations. Several factors exacerbate this phenomenon such as the climate dryness, the geological and morphological characteristics of the terrain, the irrational use of space, population growth and the over-exploitation of vegetation and water resources. This work aims to evaluate the desertification index in the Oued-El-Maleh watershed, through the integration of key factors involved in the MEDALUS model (Mediterranean Desertification and Land Use) within a GIS. The model includes among its indexes: climate, vegetation, soil and management. Each index was obtained by the combination of sub-indexes. All the factors, measured and integrated into a geographic information system, enabled us to spatialize, on a synthetic map, the degree of the desertification effect throughout the watershed. This map is a managing tool available for decision-making regarding the selection of priority areas in the fight against desertification. High sensitivity to desertification class represents only 35% of the watershed. This class is concentrated in the north of the study area that corresponds to plains and low altitude. This could be explained by the dominance of agro-pastoral activity and the presence of a big population pressure.

Le changement climatique constitue un grand défi à relever par les politiques publiques et les gestionnaires des espaces naturels. La compréhension de ses impacts sur les écosystèmes forestiers constitue un préalable nécessaire à toute réflexion visant leur conservation et le maintien des services écosystémiques qu’ils offrent. Cette étude s’est intéressée à la modélisation de la distribution potentielle de Cedrus atlantica Manetti, à l’identification des variables environnementales conditionnant sa distribution, et à la définition de l’étendue géographique des aires qui sont favorables à sa présence sous les conditions climatiques passées, actuelles et futures. Ce travail a été réalisé en se basant sur le principe d’entropie maximale. La cartographie des aires potentielles révèle la sensibilité du cèdre aux changements climatiques passés et suggère une grande étendue (quadruple de la surface d’occurrence actuelle de l’espèce) des zones bioclimatiquement adaptées au développement de cette espèce sous les conditions climatiques actuelles. Cependant, les distributions potentielles futures semblent être dépendantes de certains sites spécifiques et risquent d’être affectées négativement par le climat futur. Ces résultats mettent en évidence l’ampleur des régressions projetées des superficies du cèdre dans le futur, ce qui pourrait impacter considérablement les fonctions et services de cet écosystème et augmenter les risques d’extinction locale. Ils constituent par ailleurs un bon outil de prise de décision pour les gestionnaires du territoire quant à la conservation de ce précieux écosystème forestier, afin d’éviter toute extinction de ce foyer de biodiversité marocaine.

The concept of ecosystem services (ES) is increasingly used to analyze the relationships and interactions between humans and nature. Understanding the ecosystem services’ flow and the ecosystems’ capacity to generate these services is an essential element in considering the sustainability of ecosystem uses and the development of ecosystem accounts. For such purpose, we conduct spatially explicit analyses of nine ecosystem services in the Maamora forest, Morocco. The ecosystem services included are timber and industry wood harvest, firewood harvest, cork gathering, forage production, acorn gathering, forest carbon storage, and recreational hiking. Results make it possible to distinguish between the forest capacity to provide ecosystem services from their current use (demand) and assess them quantitatively. It came out that both capacity and flow differ in spatial extent as well as in quantity. Distinguishing capacity and flow of ES also provided an estimate of over-or under-utilization of services, and offer the possibility to map the ecosystem service provision hotspots (SPA) and degraded SPHs. The respective assessment of capacity and flux in a space-explicit manner can therefore support the monitoring of the forest ecosystem use sustainability.

Global warming is becoming a major concern affecting many components of the biodiversity at a global scale and disproportionately affecting the integrity of ecosystems, particularly the habitat of endemic species. Understanding its impacts on most vulnerable species is essential to improve knowledge on the ecology of these species and for their long-term management and conservation. Abies marocana Trabut (Moroccan fir), a remarkable forest tree of the Mediterranean basin, is an endangered species that is present in discreet small areas of the Rif Mountains, which is highly vulnerable to the ongoing climate warming and facing severe anthropogenic pressures. For conservation and management purposes, our work focused on improving understanding of the impacts of future climate change on the distribution of this species through its habitat suitability modeling. The maximum entropy approach was used, which achieved good predictive abilities. Habitat suitability was identified and then predicted under current and future climate conditions. A significant change and a gradual regression of the habitat suitability to A. marocana was shown under different future climate scenarios. The magnitude of the simulated changes is important and tends to have negative consequences for Moroccan fir conservation. For this purpose, outputs from models are useful to improve our knowledge about the ecology of A. marocana, and predictive maps produced under current and future climate conditions constitute reflection tools available to scientists and managers to better integrate actual and future climate impacts into existing and upcoming management strategies to prevent any future locale extinction.