Cladocera (Crustacea: Branchiopoda) in lowlands of the Ciscaucasian Region, European Russia

Paradoxically, attention of experts on cladoceran biogeography is focused in Russia on the Arctic zone, Far East and Siberia, while Caucasus and Ciscaucasia are studied inadequately. The aim of this communication is to analyse the cladoceran fauna of lowlands of the Ciscaucasian Region to determine general regularities of their distribution, i.e. to reveal local biodiversity hotspots of the region. In total, 171 qualitative samples from 155 water bodies are analysed where 57 species of Cladocera are recorded. All taxa are assigned to the following geographic faunistic complexes: (1) widely distributed Eurasian (WE), (2) southern tropical (ST), (3) Mediterranean-Ponto-Caspian endemic (EN), (4) arid (AR) complex; and two artificial groups: (5) widely distributed non -revised taxa (WS) and (6) eastern (possibly, anthropogenic) invaders (IS). Distribution of faunistic complexes between two main biotopes in Taman and Other Ciscaucasia is significantly different: it is relatively similar for benthic + littoral (BP) species, but very different among the planktonic species (PL). Among PL species in the Taman sub -region, the portion of EN, IS and AR species is significantly higher and rate of WE and WS is significantly lower as compared to the Other Ciscaucasia. To date we have no explanation for such specificity of the Taman region. Also we cannot discuss the endemism hotspots of the Ciscaucasia and even Caucasus concerning the Cladocera, moreover, no one cladoceran taxon is regarded as an endemic of the Caucasus. The cladoceran studies need to be continued in this region.