Floristic diversity and Ecology of EpilithicDiatoms of the ChottChergui wetland (North-West of Algeria)

This study is a phytoecological approach aimed to improve the knowledge on diatoms and their ecology in the wetland of ChottChergui in the northwesternregionof Algeria.For this work, 60 samples of solid substrates containing the epilithic diatom flora were collected in the field using a subjective method. The identification of diatom taxa was carried out according to a standard protocol while using pertinentliteraturethat specialized guides. At the level of the 5 sampling sites, water physicochemical parameters that could influence the distribution of diatoms were measured. The results obtained made it possible to recognize 36 diatom taxa belonging to 12 families, of which, the most dominant were Naviculaceae, Surirellaceae and Bacillariaceae. The calculated biodiversity indices (Shannon’s H and equitability revealed a low taxonomic richness which will probably be explained by the dominance of the typical brackish water taxa such as Mastogloiabraunii, Campylodiscusclypeus ,and Navicymbulapusilla. We were also able to characterize the distribution of identified taxa according to the physicochemical parameters of each site. Furthermore, the attraction of the diatomic communities to saprobia shows the predominance of the two classes: α-mesosaprobic and β-mesosaprobe during the two seasons of fall and spring. Canonical correspondence analysis revealed that the distribution of diatom communities is positively correlated with conductivity and temperature. Some species like Navicymbulapusilla, show a significant resistance to anthropogenic eutrophication.