Biological heritage, water quality, and vulnerability factors of the Amghass water bodies (Middle Atlas, Morocco): an integrated assessment of a high-altitude hydrosystem subject to anthropogenic and climatic pressures.

Global biodiversity is declining due to climate change and intensifying anthropogenic pressures, ranking wetlands among the most threatened ecosystems worldwide. In Morocco, continental waters are particularly rich for North Africa, underpinning key socio-economic activities and hosting significant biological heritage aligned with Ramsar criteria. This study focuses on three artificial reservoirs (Amghass I, II, III) in the Middle Atlas, fed by cool, fresh springs that sustain favorable physicochemical conditions for aquatic life. Despite their ecological and socio-economic importance, these hydrosystems face increasing pressures from demographic growth and recurring droughts. The research aims to characterize biological richness and identify vulnerability factors impairing their functional integrity. Methodologically, diachronic physicochemical analyses and biological assessments using the Standardized Global Biological Index (IBGN) were conducted. Benthic communities were dominated by crustaceans and mollusks. Inventory data recorded eight avifaunal families and seven fish species, including the otter (Lutra lutra), an umbrella species. However, anthropogenic-driven habitat regression and fragmentation have severely restricted species distributions to isolated Rifian and Atlasic refugia. Environmental threats are further evidenced by the infiltration of domestic effluents and agricultural inputs into groundwater and supplying watercourses, alongside visual and olfactory pollution degrading site aesthetics and salubrity. These cumulative impacts compromise the dynamic equilibrium of these lacustrine ecosystems, highlighting the urgent need for implementing conservation management measures to ensure their long-term sustainability.