Structure and trophic organisation of the macrobenthic community of the Hassar stream after installation of the Mediouna wastewater treatment plant (Casablanca, Morocco)

Abstract

The goal of this research is to assess changes in the structure of benthic macroinvertebrate Functional Feeding Groups (FFGs) in the Hassar Stream (north-east of Casablanca) after the Mediouna wastewater treatment plant (WWTP) was installed. Over the course of a year, from November 2013 to October 2014, data on water quality and macroinvertebrate fauna are gathered at seven sampling stations. To measure the resilience of FFGs, macroinvertebrates are used to analyse the influence of physicochemical water quality on their organisation. Based on FFGs abundance, Collector-gatherers make up 39.06 percent of the macroinvertebrates’ assemblage, followed by shredders (28.41 percent) and collector-filters (28.41 percent) (18.76 percent). Except for the upstream stations (S1 and S2), the FFGs ratios indicated that the environment is largely heterotrophic, has a significant relationship with riparian inputs, and generally stable substrates. These findings emphasise the necessity of researching macroinvertebrate FFGs as a supplement to measuring the ecological integrity and resilience of rivers after anthropogenic impact reduction.