INDICATOR ZOOPLANKTON SPECIES AND ECOLOGICAL REQUIREMENTS OF ZOOPLANKTON COMMUNITIES IN MAN-MADE RESERVOIRS

Abstract

In the present study, eleven man-made reservoirs were visited between 17 and 20 June 2009 and 18 and 21 July 2010 to determine ecological requirements of zooplankton communities by major environmental variables (water temperature, dissolved oxygen concentration, pH, conductivity). The water temperature, dissolved oxygen concentration, pH, conductivity values during the study among the sites ranged between 15.6-28.3 degrees C; 7.94-13.4 mg L-1; 8.07-8.66; and 219-464 (mu S cm(-1)), respectively. Major limnological variables showed significant differences both temporally (between years) (except for DO and EC) and spatially (i.e. sampling sites) (p < 0.05). A total of 62 taxa of zooplankton represented by 41 Rotifera, 11 Cladocera, and 10 Copepoda was identified. The most common species were rotifers Keratella cochlearis (Gosse) (11 sampling sites), Asplanchna priodonta (Gosse) and Synchaeta oblonga Ehrenberg, Polyarthra vulgaris (Carlin) (10 sampling sites), cladocerans Bosmina longirostris (Muller) and Chydorus sphaericus (Muller) (11 sampling sites) and copepod Acanthocyclops venustus (Norman & Scott) (6 sampling sites). Predominant and also most of the other identified species in the present study were known as eutrophication indicators. Species richness (as total number of species) of the sampling sites changed between 9 (Utuk reservoir) and 27 (Kirazoglu reservoir). Abundances of main taxonomic zooplankton groups were similar but varied temporally and spatially. Sampling sites were determined as beta-mesosaprobic. Statistically, cladoceran C. sphaericus was determined as the indicator species throughout the study, which is common and resistant to the wide range conditions. The results of the present study are generally indicative of unpolluted waters. All of the identified zooplankton species are the first report for the studied water bodies.