Autumn, winter and spring fauna of Cladocera in lakes and reservoirs of Jiangsu province, East China

Cladocera (Crustacea: Branchiopoda) of seven large lakes in Jiangsu province, East China were studied during November 2023, January 2024, and March of 2024. Our study reveals 46 species of Cladocera, two of them, Coronatella jejuana Sinev, Lee & Kotov, 2022 and Daphnia (Daphnia) sinevi Kotov, Ishida & Taylor, 2006, are new for China. Among them, in total, 22 species were predominantly Boreal, 15 species have core area of distribution in the south part of the temperate zone and subtropics, and 17 were tropical species.

Concerning the seasons, 40 species were found in November, 17 in January, and 25 in March. Our study revealed two opposite overwintering strategies in local Cladocera composition. Species of subtropical and tropical origin, as well as some species of Boreal origin, produce resting eggs in November and disappear in winter.

All 17 species present in January, in contrast, form parthenogenetically reproducing overwintering populations. Our data confirm the hypothesis on the East China Plain as a transitory zone between Boreal and Tropical faunistic complexes of Cladocera.