Distribution patterns of Ephemeroptera, Plecoptera, and Trichoptera (EPT) species in the northwestern Rif: environmental and climate change impacts

At intermediate spatial scales, the distribution of Ephemeroptera, Plecoptera, and Trichoptera (EPT) species is significantly influenced by the environmental characteristics of riverine habitats. These freshwater organisms are sensitive to changes in stream flow and water temperature, which can significantly affect their diversity and community structure. This study examined variations in thermal regimes, geochemical conditions and hydrological factors, and their effects on EPT assemblages across 34 sampling sites in the Northwest Rif region of Northern Morocco. Between 2021 and 2022, a total of 7,575 EPT individuals were collected, with Baetis punicus being the most prevalent species. A significant variability in taxonomic richness was observed among the sites, with mid-order streams consistently displaying the highest levels of richness along longitudinal gradients. Notably, the Tassikeste site (S9) supported the highest diversity of mayflies, establishing it as a key habitat for this taxon. These findings are essential for understanding how EPT communities respond to environmental gradients and human-induced changes, providing valuable insights for conservation and management efforts in the Rif region.