Biotypology of stream macroinvertebrates from North African and semi arid catchment: Oued Za (Morocco)

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.