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INFLUENCE OF MACROPHYTE DEVELOPMENT IN THE ZOOPLANKTON STRUCTURE FORMATION IN THE LOWER REACHES OF THE VOLGA RIVER DELTA

Authors: Litvinova N. V., Fedyaeva L. A.

The cattail, reed and bur-reed association is the cenosis-forming ones for a part of the mouth of the Kutum duct of the kultuk area of the Volga river delta. The insular area of the avandelta is characterized by reed–mace associations. The terrestrial and aquatic vegetation begins to grow massively in late May. The aquatic vegetation begins to die since the end of July whereas the terrestrial vegetation, on the contrary, reaches its maximum in this period.

SPATIAL HETEROGENEITY OF THE ICHTHYOFAUNA OF NORTHERN EURASIA AND ITS BIOGEOGRAPHICAL DIVISION

Authors: Ravkin Y. S., Yadrenkina E. N., Interesova E. A., Bogomolova I. N., Yudkin V. A., Lyalina M. I., Kosareva A. M.

Biogeographical division of Northern Eurasia (within the former USSR borders) was carried by the results of our cluster analysis of the fish fauna from 597 sites according to the BIODAT database territory division. Our classification obtained on the basis of the Jacquard similarity coefficients includes 2 regions, 12 dominion, 8 provinces, and 11 districts. The offered division considers 67% of the similarity coefficient dispersion of the fauna analyzed, which is by 21% higher than an earlier developed scheme (Berg, 1962) which includes a bigger area of the continent.