ODONATES COMMUNITY ECOLOGY AND DIVERSITY OF SOME HABITATS IN NORTHERN ALGERIAN SAHARA

Abstract

Odonata diversity is examined in the northeastern region of the Algerian Sahara by sampling 12 potential sites (one chott, 7 palm groves and 4 lakes) on a 470 km transect. This region of the lower Sahara is endowed with the most important oases and several wetlands, a geomprphology with a south-north slope involving a drainage network and an altitude gradient. A lack of updated studies in this region prompts a specific inventory and ecological analysis of the odonate stand over a 22 months period between 2012 and 2020 to determine the variables and scales that maintain this stand. The odonatofauna recorded corresponds to 21 species divided into 7 Zygoptera and 14 anisoptera (52.4% Libellulidae; 33.3% Coenagrionidae and 14.3% Aechnidae). The distribution type indicates that accidental category represents 66,7% of the population. The accessory species correspond to 23.8% while 4.7% are ubiquitous and constant respectively. At low elevation sites (-100 m), the Shannon- Weaver diversity index shows its highest value (2.70 bits). The lowest value (H'=1.35 bits) is noted at altitude above 300 m. The spring migration of Anax ephipigger is observed in Ouargla (south-east of Algeria) towards the north. Spring and summer are the richest in species, with 2 and 15 species respectively. The breeding status indicates that for the most part the species are indigenous whose reproduction is probable to certain (Crocothemis erythraea) in the drains in palm groves. The IUCN status reveals that 2 species are endangered (Coenagrion mercuriale and Acisoma panorpoides ascalaphoides). The species Enallagma deserti is endemic to North Africa