The natural factors and anthropogenic stressors influence on Chironomidae communities of two north-African wadis

Abstract

Mediterranean streams reveal high biodiversity and play a crucial role for local populations. North African wadis are less known than European streams. Hence, there is a need to explore factors influencing their communities. Chironomid assemblages of the Seybouse and El Kebir-west wadis, located in Algeria, were surveyed between July 2016 and July 2017. Among 28,045 collected larvae, 51 taxa were identified. The obtained results indicate that wadis saprobity, conductivity and pH vary seasonally. Air temperature and precipitation affect wadis differently in summer and winter. Two gradients driven by altitude define the river continuum: (1) the bottom substrate, from coarse to fine, and water quality, (2) the variety of meso-habitats from natural to anthropogenic. El Kebir-west, as a natural wadi, has unified communities throughout all its length. Communities of Seybouse vary due to the fact that this larger river is strongly influenced by human activity. Water management in Algeria should focus equally on water quality and natural habitats treatment.