A historical overview of the leech fauna of Morocco, based on both literature data, museum collections and new material, sampled in more than 100 sites in the Moulouya River basin (eastern region of Morocco), is provided. Twenty species from five families and ten genera are currently known, of which Helobdella europea Kutschera, 1987, is a new record for the country and North Africa as a whole. Herein, we add many new distribution records. The current list will need to be revised as new species distributions are recorded in the region. Notes on the species distribution are given along with comments on their habitat preferences. A concise biogeographic analysis outlines the similarities in the distribution of some species at regional and continental scales. This contribution is intended to provide information concerning the leech fauna of Morocco and is considered a foundation for future studies.

Melloulou River, which is located in Middle Atlas of Morocco, is a good example of a very wet and poorly known basin, and therefore of special conservation concern. The aim of this study was to draw up an initial inventory of the benthic macroinvertebrates taxa, and to analyze its longitudinal distribution in the basin, particularly searching for the main abiotic factors addressing its zonation for improving future management and conservation actions. The study allowed identifying 161 taxa belonging to 127 genera and 80 families, most new records for northeast Morocco. The biotypology, which was studied by using Foucart' Factorial Correspondence Analysis (FCA), Partial Triadic analysis (PTA), and IndVal showed a longitudinal distribution of macroinvertebrates mainly governed by altitude, slope and current velocity. The studied biota revealed the presence of three assemblages and an important number of ubiquitous species not included in any group. The first group is located in the upper courses of Melloulou River representing a community proper of a crenon-rhithron zone; the second occurs in the middle and lower courses, and clearly reflects the community of a large potamon; the third one is a mixture of taxa capable to colonize the entire study area. Our finding, highlight the singular aquatic biodiversity occurring in the Melloulou River and its extraordinary changing water dynamic over time, which are key factors for future monitoring, as well as managing and conservation actions.

This work presents currently available knowledge on alien species (AS) found in the inland waters of Morocco. The objective is to provide an updated list of alien species and identify the main introduction pathways and possible threats to native biodiversity. The dataset was built from an extensive literature search supplemented by our own research work (published or in progress). The main areas harboring xenodiversity in Moroccan freshwaters correspond to protected areas (e.g., Ramsar Site and SIBE). These areas are currently home to 41 confirmed AS belonging to different taxonomic groups. Fish are the most abundant taxonomic group with 21 species, followed by molluscs (7 species) and arthropods (7 species). The presence of 15 more species was also noticed but considered doubtful. Almost half of these AS were introduced intentionally. They correspond to restocking programs and are likely the most serious threat to native biodiversity through predation, competition, and hybridization. Commercial activities around aquarium and ornamental species appear as the second source favoring colonization by AS. Implementing protective regulations regarding the import of exotic species in Morocco appears very urgent to protect local native diversity. In addition, detecting and monitoring the expansion of AS within the colonized areas and studies improving biological and ecological knowledge seem crucial to mitigate their possible impacts on native communities and preserve Moroccan freshwater ecosystems.

The aim of this study is to investigate the longitudinal zonation of macroinvertebrates assemblages in the Za River basin, the main tributary of Moulouya River (Morocco). This work carried out in three campaigns between March and August 2014 on 12 stations selected. This study allowed the identification of 137 species classified in 109 genera and 65 families. In addition to the physicochemical parameters measured three times in each station, a description of the aquatic environment was made to characterize each of the stations surveyed; in particular with regard to altitude, slope, Emberger quotient, thermal amplitude, kilometers at the source, current velocity and bioclimatic zones. The treatment of this benthic population as well as the stations environmental descriptors, using Foucart' factorial correspondence analysis (FCA) and partial triadic analysis (PTA) respectively, allowed for the development of a typology of this watercourse, where altitude and current speed seem to play a major role in the distribution of benthic invertebrates. The biocenotic study revealed the presence of three stationary groupings corresponding to four faunal groups.

In 2014–2019, we carried out an examination of Trichoptera of the Moulouya River basin in the Oriental, Fèz-Meknès and Drâa-Tafilalet regions of Morocco. Caddisflies of the territories of the High Plateau, the oriental Sahara and the eastern parts of the Rif, Middle Atlas and the High Atlas have been studied for the first time. We collected and identified 41 species. Rhyacophila sp. cf. intermedia/rougemonti McLachlan, 1868/McLachlan, 1880 (Rhyacophilidae); Hydropsyche sp. cf. exocellata Duföur, 1841 (Hydropsychidae) and Mesophylax aspersus hoggarensis Malicky, 1998 (Limnephlidae) are reported for the first time from Morocco. 21 species are recorded for the first time from Oriental Region and 13 species from Drâa-Tafilalet Region. For previously recorded species, we present additional distributional data. Additionally, we provide taxonomic notes on larvae of Athripsodes sp., Rhyacophila sp. and Mesophylax sp. cf. impunctatus McLachlan, 1884. We found a clear dominance of the Palearctic elements, typically Mediterranean, and a high rate of Ibero‐Maghrebian endemics in the Trichoptera fauna of northeastern Morocco. This chorotype pattern is similar to patterns observed for other aquatic insects in the same study area.