Towards a Comprehensive Inventory of Freshwater Macroinvertebrates in Northeastern Morocco: Diversity Patterns, Endemism, and Potential Implications for Aquatic Ecosystem Sustainability

Freshwater macroinvertebrate diversity remains unevenly documented across North Africa, limiting the use of biodiversity data in conservation planning. Here, we provide a regional synthesis of freshwater macroinvertebrates from the Moulouya River basin and the Eastern Region of Morocco, integrating records from historical literature, expert knowledge, and recent field observations. The dataset documents 525 species, 269 genera, 114 families, and 4924 georeferenced occurrence records compiled between 1914 and 2026. Taxonomic representation was highly uneven, with aquatic insects dominating the dataset and several small-bodied, cryptic, subterranean, and taxonomically difficult groups remaining poorly documented. Chorological analyses revealed a predominance of Palearctic taxa with Mediterranean affinities, together with a substantial proportion of Moroccan, Maghrebian, and Ibero-Maghrebian endemics. Strict Moroccan endemics were especially concentrated in gastropods and were mainly associated with lotic ecosystems and springs. Spatial and temporal patterns revealed apparent richness concentrations in northern and western sectors of the study area, but also strong biases linked to uneven sampling effort. This synthesis provides a baseline for future monitoring, highlights priority habitats and taxonomic gaps, and offers actionable insights to support sustainable water resource management and ecosystem resilience under accelerating climate change and anthropogenic pressures in North African arid and semi-arid regions.