UDC 574.587

Zinchenko T.D., Shitikov V.K., Rosenberg G.S. ASSESSMENT OF BOTTOM COMMUNITIES OF RIVERS TAKING INTO ACCOUNT “DARK AND GRAY VARIETY” OF SPECIES: APPROACHES TO THE SOLUTION // Arid Ecosystems. 2023. Vol. 29. № 4 (97). P. 177-186. | PDF

The species diversity of the entire meta-community is composed of local pools of species of individual communities, including both a set of actually observed taxonomic groups and species of «dark» diversity, which by their ecological properties are theoretically suitable for habitat in the existing conditions and are potentially found in repeated studies. To assess the dark diversity, quantitative indices of suitability are calculated for the surveyed areas of the study area in relation to the various taxa of the community in question. The species composition of bottom communities was studied in small and medium plain rivers, tributaries of Kuibyshev, Saratov and Volgograd reservoirs, including rivers of arid region of Lake Elton basin. A total of 132 local communities were surveyed from which 147 macrozoobenthos taxa were selected for calculations. Analysis of co-occurrence of species was carried out to identify dark diversity and, using formulas of hypergeometric distribution, estimates of conditional probabilities of statistical association of each of these species with certain river sections were calculated. Dependencies between observed species richness and dark diversity were considered; the occurrence of latent species in river sections of similar type was tested. We introduce the concept of «gray» diversity, a subset of observed species with focal area indices less than a given threshold.

This work was performed according to the research topic «Assessment of current biodiversity and forecast of  its changes for the ecosystems of the Volga river basin under conditions of their natural and anthropogenic transformation» and with the financial support of the Russian Foundation for Basic Research, grant № 17-04-00135.

Keywords: macrozoobenthos, small and medium rivers, species pool, dark and gray diversity, matching index, co-occurrence, hypergeometric distribution.

Funding. The work was carried out on the research topic «Change, sustainability and conservation of biological diversity under the influence of global climate change and intense anthropogenic pressure on the ecosystems of the Volga basin. The registration number of the state task is 1021060107212-5-1.6.20; 1.6.19 and with the financial support of the Russian Foundation for Basic Research, grant No. 17-04-00135 «Functional features of the organization of the structure of planktonic and bottom communities of river ecosystems on the example of salty rivers of the hypergaline lake basin. Elton.»

DOI: 10.24412/1993-3916-2023-4-177-186

EDN: ZZAMBH