Experimental Research of the Influence of Beavers’ (Castor fiber L.) Vital Activity Products on the Forming of Zooplankton Community Structure (Illustrated by the Example of Growth of Two Different Sized Species of Cladocera
A. V. KRYLOV1, I. V. CHALOVA1, N. S. LAPEEVA1, O. L. TSELMOVICH1, A. V. ROMANENKO1, V. L. LAVROV1,2
1I. D. Papanin Institute for Biology of Inland Waters, RAS, 152742, Yaroslavl Oblast, Borok
2Voronezh State Nature Biosphere Reserve, 394080, Voronezh
Keywords: жизнедеятельность бобров, разноразмерные виды, Daphnia (Ctenodaphnia) magnа Straus, Ceriodaphnia dubia Richard, численность, биомасса, бактериопланктон, биотестирование, beavers’ vital activity, different sized species, Daphnia (Ctenodaphnia) magnа Straus, Ceriodaphnia dubia Richard, number, biomass, bacterial plankton, bioassay
Abstract
Microcosm experiments showed that beavers’ vital activity products (BVAP) promoted the increase of nitrogen (N) and phosphorus (P) concentration, the decrease of the N / P ratio in water, the increase of the number and biomass of bacterial plankton. In these conditions, the number and biomass of small-sized Ceriodaphnia dubia Richard and large-sized Daphnia (Ctenodaphnia) magna Straus, which lived separately in microcosms, raised. The cohabitation of these cladocerans in microcosms under the BVAP influence resulted in a more intensive increase in the number and biomass of Daphnia magnа . The similar cohabitation without the BVAP influence led to the predominance of Ceriodaphnia dubia . Bioassay showed that the fertility of Ceriodaphnia dubia decreased in the water which was heavily populated with Daphnia mаgnа under the BVAP influence. It was suggested that the vital activity products of large-sized Daphnia species inhibit the fertility of small-sized Cladocera species. This fact, along with the high competitiveness of large cladoceran species under conditions of a high level of nutrition, determined the forming of the zooplankton communities in beaver ponds, which were characterized by the high number and biomass and the low uniformity.
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