Contribution To The Ecological Study Of Epigean Cladocera And Copepoda (cyclopoida) From Groundwater In Northern Tunisia

The present study is a contribution to the biogeography and ecology of cladocera and copepoda Cyclopoida, from groundwater in Bizerte area (Northern Tunisia) throughout an annual cycle (November 2006 - October 2007). Eleven taxa of Crustacean were sampled and identified: four cladocera (Ceriodaphnia reticulata, Ceriodaphnia laticaudata, Daphnia magna and Daphnia similis) and seven copepoda cyclopoida (Cyclops abyssorum mauritaniae, Eucyclops lilljeborgii, Thermocyclops dybowskii, Acanthocyclops rhenanus, Eucyclops macruroides, Macrocyclops albidus and Diacyclops sp). C. abyssorum mauritaniae was sampled for the first time in Tunisia, in Rimel's well near the Rimel Sea in Bizerte. The relationships between taxa and the measured environmental and spatial variables (Temperature, Salinity, Conductivity, Turbidity, pH and Depth) were examined using both unconstrained (Principal Components Analysis, PCA) and constrained (MDS) ordination techniques. The MDS ordination according to biotic and physico-chemical parameters allowed grouping stations in four distinct habitats according to the ecological preferences of its species. D. magna, D. similis and C. abyssorum mauritaniae seems tolerate waters with high salinity and turbidity. C. reticulata colonize biotopes characterized by neutral pH and a low water temperature. In contrast, M. albidus shows a relatively tolerance to warmer water and E. macriroides colonizes deep ecosystems characterized by a low conductivity.