Cladocera and Copepoda of Montane Peatlands of the North Caucasus, Russia: Composition and Formation Patterns of Species Complexes

In 2018, the faunas of Cladocera and Copepoda of four mountain Sphagnum peatlands in the Republic of North Ossetia and five in the Republic of Kabardino-Balkaria, Caucasus, Russia, were studied. For each area, species complexes peculiar both to the central part of the secondary water body and to the surrounding Sphagnum floating mat, at the edge of the water, were described. Altogether, 31 species of microcrustaceans were found in the material collected. Among them, two species of Cladocera and eight species of Copepoda were recorded from mountain water bodies of the North Caucasus for the first time. Montane Sphagnum peatlands were shown to be an outpost of northern species distributions, as confirmed by finding two Copepoda species typical of more northerly regions. The abundance of microcrustaceans in floating Sphagnum mats was often tens of times higher than in the water column. The habitat type, seasonality, latitude, longitude, altitude, temperature, acidity, and mineralization combined were shown to explain only 32.3% of variations in the species complexes. This indicates a complex factor regulation of the community structure in high-altitude conditions.