Characterization of aquatic macroinvertebrates in the running waters of Ifrane: (Middle Atlas of Morocco)

This study focuses on characterizing the macroinvertebrate fauna of the Oued Sidi Rached, located in Ifrane National Park within the Atlas Cedar Biosphere Reserve. Sampling conducted between March 2024 and February 2025 using a Surber and Dip net sampler enabled the development of an inventory of benthic biodiversity. The results show that, upstream, the communities are dominated by arthropods, with a high abundance of amphipods of the genus Gammarus (Gammaridae). The presence of sensitive taxa, particularly Ephemeroptera and Trichoptera, indicates a good overall ecological status, confirmed by a high IBGN index. In contrast, the downstream zone is characterized by a decrease in sensitive taxa and a relative increase in tolerant organisms, such as Diptera and Oligochaeta. This shift in community structure reflects a progressive deterioration in water quality, likely linked to diffuse anthropogenic inputs, particularly associated with agricultural and tourism activities. This study highlights the importance of macroinvertebrates as bioindicators of aquatic ecosystem quality. It emphasizes the variation in the ecological gradient along the stream and provides a useful scientific basis for monitoring, managing, and conserving these environments.