Spatiotemporal dynamics of endemic macroinvertebrates in the Martil Basin (Morocco): Responses to hydroclimatic variability and anthropogenic disturbances

Abstract

This study investigates the responses of endemic macroinvertebrate species in the Martil River Basin (Morocco) to physic o chemical (T, pH, Cond and DO), land use, biotic indices (IBMWP, IHF and QBR), and hydro-morphological factors. Sampling was conducted over four seasons (2017) at 19 stations, revealing 1,768 individuals belonging to 32 endemic species. Hydro p syche iberomaroccana was the most abundant species, while Choroterpes volubilis was the most widespread. Biogeographical analysis highlighted a high proportion of Ibero-Maghrebian endemics. Multivariate analyses revealed significant biotypological differences among stream types, with sensitive endemic species predominantly found in highland / midland permanent stations, positively correlated with dissolved oxygen, altitude, and biotic indices. In contrast, lentic, thermophilic, and eurytopic species were more common in downstream areas, exposed to agricultural, industrial, and urban activities, and associated with higher temperatures and pollution levels. Seasonal and spatial variability in taxonomic composition was strongly influenced by hydr o logical intermittency and human pressures, with endemic species diversity and abundance peaking in spring. Despite their ec o logical importance, with the exception of Odonata, none of the species from other orders are currently listed on the IUCN Red List or in Annex IV of Moroccan Law 29-05 concerning the protection of wild flora and fauna species and the control of their trade. The findings underscore the urgent need for targeted conservation strategies to address threats from climate change, habitat degradation, and anthropogenic activities.