First Data on Species Composition and Development Cladocera (Crustacea: Branchiopoda) in Mire Ecosystems (Kaliningrad Region, Russia)

The original data on Cladocera fauna in standing-water and stream habitats of mire ecosystems were obtained for the first time in the Kaliningrad region during the research study on large raised bogs (Zehlau and Bolshoye) and drainage canals of 6 peatlands affected by peat extraction. In the studied wetland ecosystems, 41 species of Cladocera were recorded in total, including a number of rare and vulnerable taxa (Flavalona rustica, Scapholeberis microcephala, Streblocerus serricaudatus and Holopedium gibberum). The four species of Cladocera are new species for the Kaliningrad region which were not reported here before. Cladocera played a vital role in the studied bog pools and waterlogged habitats in peatlands as a key group of organisms that forms here a significant part of the zooplankton biomass due to the abundance and intensive production in the water bodies. The secondary filter feeders and predators were the most abundant in bog ecosystems. The cladoceran fauna in the intact bog ecosystems, especially the Zehlau raised bog, was the most diverse and unique. Nevertheless, the cladoceran assemblages in the disturbed ecosystems of drainage canals retained certain features of the natural water bodies. The latter fact is important in applied respect enabling to consider these canals as refugia that have potentials for natural restoration of the cladoceran fauna during the peatland rewetting programme on the Carbon Polygon in the Kaliningrad region.