engleski

Littoral macroinvertebrate communities in reservoirs of the Dinaric karst of Croatia

Reservoirs are man-made water-bodies predominantly created by using a dam or a lock to store water that may be used for irrigation, flood control or production of electric en- ergy. Reservoirs could provide important habitats for birds, fish and other aquatic organ- isms. Macroinvertebrate communities were studied at nine reservoirs located in the Dinaric ecoregion of Croatia during July and September 2016. At each reservoir, one study site, with the lowest anthropogenic influence was selected. The littoral zone was sampled, on a surface area of 250 m2 or less, depending on the incline of the bank. At each sampling site, four levels of depth were defined in 25 cm segments to 1 m total depth (0 to 0.25 m, 0.25 m to 0.5 m, 0.5 m to 0.75 m and 0.75 m to 1 m). Ten samples were collected at each site using benthos hand net (25 cm × 25 cm ; 500 μ m). Physico-chemical water properties were measured: dissolved oxygen concentration, oxygen saturation, electrical conductiv - ity, pH and alkalinity. Significantly higher population densities of Oligochaeta (p < 0.05), found in deeper littoral reaches of all reservoirs, were most probably related to substrate characteristics and their tolerance in terms of oxygen demands. On the contrary, Odonata and Ephemeroptera were significantly more abundant (p < 0.05) in shallower littoral parts of the reservoirs, due to higher variability of microhabitats and higher demands for oxygen concentrations. Results of this study provide new information about the ecology of benthic macroinvertebrates in reservoirs of the Dinaric karst

Macroinvertebrate ; Reservoirs ; Littoral

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