Résumé:
This study was carried out to evaluate the variation of diversity and composition of
macroinvertebrate community in streams, along an altitudinal gradient in in three lotic
ecosystems in northeastern Algeria in Aurès region, oued Tesserift, Oued Benifdhala and
Oued Hamla. We conducted our sampling between May and June 2022. The altitudinal
gradient varies between 930 m and 1260 m. We counted a total of 120 specimens of macro invertebrates distributed over two phyla (Molluscs and Arthropods), two classes (Gasteropods
and Insects), 07 orders, 16 families. Both diversity and abundance of studied macro invertebrates vary with altitudinal gradient. The highest values of diversity were found in the
altitudinal zone of Hamla (up to 1200 m, total taxa richness = 22 and Shannon index = 2.64).
The number of individuals in the altitudinal zone of Tesserift is higher than in all the other
altitudinal zones ( individuals number = 59). The preliminary results show that the altitudinal
gradient is in favour of high diversity but in disfavour of population abundance
