Seasonal distribution of Ephemeroptera (Insecta) of the Kizilirmak Basin with evaluation of the water quality based on physicochemical parameters and benthic metrics

This study was carried out to determine the seasonal distribution of the Ephemeroptera of the Kizilirmak Basin and to evaluate the relations of the identified taxa with the physicochemical variables in their distribution areas, to reveal the ecological water quality through both these parameters and the benthic metrics developed for the Kizilirmak basin. Field studies were carried out in 13 different localities in spring, summer and autumn periods in 2018. A total of 990 individuals were examined and 27 species belonging to seven families were identified. Species diversity according to Shannon-Wiener (H) values was highest at station 8 (1.52) and lowest at station 7 (0.23) in the spring period, highest at station 3 (1.49) lowest at station 7 (0.23) in the summer period, and highest at the 2nd (1.44) and lowest at the 4th (0.14) station in the autumn period. According to the calculated average H values of the stations, the stations 4, 6, 7, 10 and 12 were determined in the polluted water class, while the other stations were determined in the moderate polluted water class. According to cluster analysis; the highest similarities were seen between the station 1 and the stations 2 and 9 (71%). According to the ANOSIM result, in which the differences between the seasonal distributions of the species were evaluated, there was a significant difference between the spring period and the summer and autumn periods. According to the result of MANOVA, which was applied to understand the differences between environmental variables and seasonal groups, there was a significant difference between spring and summer seasons in terms of temperature variable, while dissolved oxygen variable was significantly differed among all season groups. The water quality of the stations was evaluated together with the biotic index based on physico-chemical variables and benthic metrics, and the stations with reference characteristics were determined. Accordingly, in terms of both physicochemical parameter measurements and index values calculated on biological data, it was determined that the stations are mostly in reference feature (high, good and moderate quality water class) away from pollution pressure.