The relationship between zooplankton community and environmental factors of Ghrib Dam in Algeria

The effect of environmental factors on zooplankton diversity, abundance, and distribution in the Ghrib Dam water body was investigated for 2 years from June 2013 to May 2015. A total of 61 species of zooplankton were recorded, including 45 rotifers, 13 cladocerans, and 3 copepods. The zooplankton abundance fluctuated between 4 and 3363 ind.L^-1, and its Shannon-Wiener index of zooplankton diversity in Ghrib Dam varied from H' = 1.15 to 3.77 during the 2-year study period. The highest diversity index was recorded at sampling site S1 in January 2015, due to the increase of specific richness (Ni = 27, D_mg = 5.75). Canonical correspondence analysis (CCA) was used to determine the influence of environmental factors in structuring the zooplankton species for each group. The results of CCA revealed that the most significant environmental factors influencing zooplankton community were water temperature (WT), dissolved oxygen (DO), phosphorus (PO₄^-), and NO₃^- (p < 0.05, Monte Carlo permutation test). Meanwhile, the appearance of Hexarthra sp., Collotheca pelagica, and Diaphanosoma brachyurum indicated a rise in WT. The existence of Filinia longiseta, Keratella quadrata, and Cyclops strenuus correlated with a rising of DO. Brachionus urceolaris, Filinia passa, Keratella tecta, Notholca acuminata, and Polyarthra dolichoptera positively coexisted in an increased PO₄^-. Daphnia longispina and Oxyurella tenuicaudis were positively associated with high concentration of NO₃^-.