## 1 Introduction  
Natural ecosystems are essential support for the well-being of human populations and all living things through the multiple services they provide [1, 2]. For example, mountains, as the \"water towers\" of the world [3], are ecosystems that play a crucial role in the well-being of human populations, more than 50% of which depend on freshwater that is captured, stored, and purified in mountain regions [4]; this is especially true in arid and semi-arid areas, such as those characterized by a Mediterranean climate, where mountains act as a reservoir for the dry season and their importance depends on the durability and volume of their snow cover [3]. In addition to fresh water, mountain ecosystems provide various ecosystem services. These include providing raw materials (wood, fiber, and mineral resources), climate and natural hazard regulation, pollination [5,6], and cultural services [7]. The demand for ES is distributed differently worldwide, with ES for food, timber, fodder, and water in high demand in developing countries, whereas in rich countries, the highest demand is for recreational ES [6]. Whatever the topographic configuration in which they are located, forest ecosystems are also a source of the most fundamental ES for humans [8,9]. More than a billion people, including the world's poorest, directly depend on forests for their livelihood [10,11]. They are home to over 80% of the world's terrestrial biodiversity [10] and contribute to primary production [12]. Forests are the largest carbon reservoir of all terrestrial ecosystems and store more than 80% of all terrestrial airborne carbon (C) [13], thus contributing to climate change mitigation [10,11,14]. Mediterranean forests, considered a unique global natural heritage in terms of biological diversity [15], particularly contribute to reducing poverty in societies and maintaining local economies. These forests provide a wide range of ES [16]. In terms of provisioning services, they provide wood products (charcoal) and non-wood products (food, medicines, resins, game, etc.). The latter is extensively collected in many Mediterranean forests [17,18]. In terms of regulating services, these forests play a fundamental role in soil and watershed protection and contribute to microclimate improvements. Finally, these ecosystems have a great capacity to provide cultural and tourism ES [19]. Today, forests and mountains are under pressure and their capacity to provide all these goods and services is increasingly affected by environmental and social changes. The demand for ES continues to grow, whereas the supply of mountain ES decreased between 2000 and 2010 worldwide [6]. Even if mountain areas covered by vegetation remain better protected, especially against the risk of erosion, Mediterranean forests have to face various threats of anthropogenic and/or natural origin, such as urban development, fires, and climate change, which cause a rapid change in the water cycle (increased evaporation and decreased precipitation), drought, accelerated desertification, the displacement of biodiversity, and floods. This has an impact on the dynamics of land-use changes [17]. Thus, maintaining the availability and sustainability of ES under current global change scenarios appears to be a challenge and requires integrating ES into management strategies [20,21]. Hence, the aim of this work is to study the potential ES that mountain forests of the Mediterranean basin--one of the richest in endemism [22]-could provide. We particularly target the southern part of the basin in North Africa to contribute to research in this under-documented area. Indeed, the literature has shown that only 9% of the research articles on the multiple ES provided by Mediterranean forests come from the southern and southeastern countries of the Mediterranean basin [19]. In Algeria, forests are rare, their overall area representing nearly 2% of the total national territory and 11% of the country's north, where there is a climate favorable to the presence of tree cover [23].