The Southern Part of Russian Far East and Korean Peninsula as a Transition Zone between the Boreal and Tropical Faunas of the Waterfleas (Cladocera, Crustacea)

Abstract

Abstract: Based on original data, the most complete and updated species list of the water fleas (Crustacea: Cladocera) of both the southern part of the Russian Far East and Korea is represented. In total, 122 taxa are identified to the species level. The list includes 92 valid species recorded in the Far East of Russia and 71 in South Korea. Each taxon is attributed to one of the six zoogeographical groups: one among four faunistic complexes (widespread Eurasian, East Asian–American, endemic East Asian, and southern tropical), a group of widely distributed unrevised taxa, and a group of invasive species. With a decrease in latitude (i.e., in the north–south direction), (1) the species richness is decreased, (2) the dominance structure (based on species occurrence frequencies) is changed from two–three dominant species to a lack of clear dominants; (3) the rate of representatives of the widespread Eurasian complex is decreased, while that of the southern tropical taxa is increased, and (4) the taxocoenoses of the boreal type are changed to those of subtropical type. In addition to boreal and subtropical type taxocoenoses, three more taxocoenosis types are found in the Khanka Lake basin (the largest water body in the region). The relative abundance and occurrence of taxa from the endemic East Asian complex are similar within the entire region and do not vary with latitude.