Cladocera (Daphniidae, Chydoridae) of Ukrainian Roztocze: comparative characteristics

Abstract

The taxonomic structure of Cladocera of Ukrainian Roztocze has been studied. The basis of the work was 1754 samples collected in 1995–2016. In total 42 species of Cladocera belonging to 7 families and 19 genera have been identified in reservoirs. The family Chydoridae has 8 genera (Acroperus, Alona, Alonella, Chydorus, Disparalona, Graproleberis, Pleuroxus, Tretocephala), the family Daphniidae has 5 genera (Ceriodaphnia, Daphnia, Moina, Scapholeberis, Simocephalus). Chydoridae and Daphniidae have 18 and 17 species respectively. The representation of the Chydoridae family by the number of genera in clаdocerocenosis is 42%, and by the number of species – 43%. For the Daphniidae family, these values are respectively 27% and 41%. Among genera, the first significant functional group (15% of the total species composition) is formed by Daphnia, Ceriodaphnia (Daphniidae), the second group (10% of the total species) is formed by Alona, Chydorus, Pleuroxus (Chydoridae). Among the families, Chydoridae in the structure of cladocerocoenoses is near the Daphniidae family. They occupy different habitats and do not compete. Chydoridae are, first of all, littoral form, and Daphniidae are pelagic. Cladocera of the second trophic level is a kind of biofilter, which cleans water bodies and maintains the ecological balance of ecosystems. It has been shown that the trophic network of reservoirs is well developed. In the reservoirs of the region there are represented primarily forms, distributed in the Holarctic and Palaearctic.