Abstract
•North-eastern Algeria is a hotspot of freshwater biodiversity.•A survey of relict Mountain streams recorded ten taxa of Black Flies.•Species richness peaked in late winter/early spring.•Black Fly assemblages closely related to habitat templets.
Despite their ecological and socio-economic significance, the black fly communities of Algerian hydrosystems have been understudied. The simuliid fauna of relict mountain streams of northeastern Algeria was sampled at 24 localities in two distinct and relatively uncharted watersheds. Species richness in the El Kala Highlands varied from eight taxa in the most species-rich localities to the virtual absence of any taxon in some localities. Species richness also mirrored the hydroperiod of most localities and reached its peak in late winter/early spring. Co-inertia analysis indicated a significant co-structure between environmental descriptors and black fly assemblages, suggesting a strong influence of the habitat templet on aquatic insect community structure. A comparison with an additional survey of 23 localities spread across northern Algeria suggests distinct black fly assemblages characterizing the El Kala Highlands.