Crustaceans in the Meiobenthos and Plankton of the Thermokarst Lakes and Polygonal Ponds in the Lena River Delta (Northern Yakutia, Russia): Species Composition and Factors Regulating Assemblage Structures

Abstract

Information about invertebrates in the low-flow water bodies of northeastern Siberia is far from complete. In particular, little is known about crustaceans—one of the main components of meiobenthic and zooplanktonic communities. An open question is which environmental factors significantly affect the crustaceans in different taxonomic and ecological groups? Based on the data collected on the zooplankton and meiobenthos in the tundra ponds in the southern part of the Lena River Delta, analysis of the crustacean taxocene structure was performed. In total, 59 crustacean species and taxa were found. Five of these are new for the region. The species richness was higher in the large thermokarst lakes than in the small water bodies, and the abundance was higher in small polygonal ponds than in the other water bodies. Variations in the Cladocera assemblages were mainly affected by the annual differences in the water temperature; non-harpacticoid copepods were generally determined by hydrochemical factors; and for Harpacticoida, the macrophyte composition was significant. Three types of the crustacean assemblages characteristic of different stages of tundra lake development were distinguished. The hypothesis that the formation of crustacean taxocenes in the Lena River Delta is mainly determined by two types of ecological filters, temperature and local features of the water body, was confirmed.

Assemblages of Meiobenthic and Planktonic Microcrustaceans (Cladocera and Copepoda) from Small Water Bodies of Mountain Subarctic (Putorana Plateau, Middle Siberia)

“…The list of microcrustacean fauna of the Putorana Plateau, compiled based on the original and literature data, includes 62 species of Cladocera and 63 species of Copepoda. Such species richness is comparable to well-studied Arctic regions such as the Bolshezemelskaya tundra (55 Cladocera and 62 Copepoda) [18], the Lena Delta (37 and 82) [35,44] and the Yamal peninsula (42 and 50) [38]. The remaining known fauna of microcrustaceans of the north Eurasia, both the Far East and Siberia, and the East European Plain, trailing on average 1.5-3 times the Putorana Plateau [33].…”

“…Two factors played a key role in the formation of assemblages of planktonic fauna-the water body surface size, indirectly associated with the hydrological type (lake, small lake, or puddle), and the composition of macrophytes. The influence of the size of the water body on the species richness of microcrustaceans has been already repeatedly noted [17,35,49], etc. The larger the size of the reservoir, the higher the diversity of microbiots that a specific fauna inhabits.…”

“…The compiled species lists from the existing database on microcrustaceans [33] were used in the analysis of biogeographical status of fauna of the Putorana Plateau. Additionally, published data on Cladocera and Copepoda species richness throughout Polar zone of the Kola Peninsula, Far East, West, Middle and East Siberia [17,18,[34][35][36][37][38][39][40][41] and other were used in the compilation of microcrustacean distribution ranges database. Some parts of relatively old articles cited in a general review by Fefilova et al [18] are not separately presented in the reference list.…”

The species structure, biogeographical status, and the relation to the Beringian fauna of microcrustaceans (Cladocera, Copepoda) of the Magadan Area (Far East, Russia)

“…The B. arcticus area spans the northern regions of Eurasia [Borutsky, 1952;Alekseev, Tsalolikhin, 2010]. This species is typical for tundra water bodies [Fefilova, 2015;Chertoprud, Novichkova, 2021], and its distribution in the south is limited to the zone of sphagnum bog extension [Borutsky, 1952]. In East Siberia, B. arcticus is known from polygonal ponds of the Lena Delta [Chertoprud, Novichkova, 2021] and in small lakes from the Putorana Plateau .…”

“…This species is typical for tundra water bodies [Fefilova, 2015;Chertoprud, Novichkova, 2021], and its distribution in the south is limited to the zone of sphagnum bog extension [Borutsky, 1952]. In East Siberia, B. arcticus is known from polygonal ponds of the Lena Delta [Chertoprud, Novichkova, 2021] and in small lakes from the Putorana Plateau . Cyclopoida E. ohtakai subsumes under the group of E. speratus and was described from the Japan archipelago [Ishida, 2000].…”