Mapping Sahelian groundwater-dependent ecosystems based on an updated typology

Abstract The functionality of certain ecosystems depends on, or partially depends on, the presence of water under the ground or on its emergence to the surface. These ecosystems, referred to as groundwater-dependent ecosystems (GDEs), underpin national economies by sustaining essential goods such as fish, timber, and various nontimber products, as well as providing critical services such as water storage, purification, and flood control. Within GDEs, biotopes and biocenoses actively contribute to sustaining and improving human well-being by facilitating these vital conditions and processes. In water-scarce environments, groundwater assumes a central role at the nexus of integrated human, animal, and environmental health, known as the One Health concept. Considering the groundwater requirements of GDEs, it is then indispensable to practice sustainable water management, enabling sustainable development and shared prosperity. This paper seeks to enhance the comprehension of GDEs, enabling practical applications within the arid and semiarid regions of the Western and Central Sahel. Based on an exhaustive literature review and subsequently incorporating insights from interviews with researchers in the Sahel region, it proposes a typology for Sahelian GDEs. This typology, rooted in geomorphological, hydrological, and socioeconomic contexts, comprises four primary categories: inland surface-water ecosystems, coastal and marine ecosystems, oasis and spring ecosystems, and terrestrial vegetation ecosystems. It serves as a framework for identifying an initial set of 251 GDEs in the Sahel, addressing the challenge of limited available data in this geographic area. By integrating the socioeconomic dimension of GDEs, this work underscores the pivotal role of robust conservation policies within a developmental strategy.