Effect of Environmental Parameters on the Composition and Distribution of Gammaridae (Amphipoda-Crustacea) in Two Streams in Northern Algeria

The Gammaridae (Crustacea) represents a very important family in the functioning of lotic ecosystems and in the evaluation of the biological quality of its waters. We studied the distribution of the Gammaridae family and its relationship to environmental variables in 2013 and 2020, along 19 sampling stations located in two streams in northern Algeria, Seybouse, with ten sampling stations, and Tafna with nine sampling stations. We have collected 1299 individuals corresponding to two genera: Gammarus and Echinogammarus. We found Gammarus genus in the Tafna River’s sampling stations, which is located in north-west of Algeria, due to its moderate to poor physicochemical water quality, stony and pebble bottoms, abundant aquatic vegetation and its banks overgrown with riparian trees. Its presence is also related to the geological nature dominated by Jurassic limestone. As for the second genus, Echinogammarus, it was collected in the Seybouse River located in northeast of Algeria. These sampling stations have a substrate dominated by pebbles, large pebbles and stony bottoms, and an average abundance of aquatic vegetation. In addition, they are characterized by a poor physicochemical quality of water. The results of this study show that the distribution of the genus Gammarus and Echinogammarus is related to the environmental parameters: quality of water, riparian banks and aquatic vegetation, as well as to the substrate. There is also a difference in geographical position and nature of the geological formations between the west and the east of northern Algeria. In the Tafna River, nature is Jurassic limestone, while in the Seybouse River, Numidian sandstones, marls and limestone marls dominate.