Heterogeneity of distribution and community composition of zooplankton in upper layers of Lake Svente

Abstract

The aim of the study was to determine whether groups of zooplankton exhibit ecological heterogeneity. Investigation was done in Lake Svente, situated on the monticule of Ilukste, 137 m above the sea level, in the Svente parish in Daugavpils district (Latvia). For this study, zooplankton samples were taken on 12 July, 3 and 30 August and 21 September in 2007. The sampling was carried out in six localities of the lake with different depth. During the analysis, three zooplankton groups, i.e. Rotatoria, Cladocera and Copepoda, and 35 zooplankton species were identified. Rotatoria was the most dominant group consisting of 18 species, followed by Cladocera with 16 species and Copepoda with one species and one genus. In all sampling localities, Polyarthra vulgaris, Asplanchna priodonta, Keratella cochlearis, Conochilus hippocrepis, Kellicottia longispina and Gastropus stylifer were dominant species in the Rotatoria group. Daphnia cucullata, Bosmina crassicornis, Ceriodaphnia affinis and Diaphanosoma brachyurum were dominant species in the Cladocera group, and Cyclops sp. and Eudiaptomus graciloides in the Copepoda group.

Tyrimo tikslas – nustatyti, ar zooplanktono grupėms Šventės ežere (Latvijoje, Daugpilio rajone, Alūkstos kalvose, 137 m virš jūros lygio) būdingas ekologinis heterogeniškumas. Zooplanktono mėginiai buvo paimti šešiose skirtingo gylio ežero vietose 2007 m. liepos 12 d., rugpjūčio 3 ir 30 d. bei rugsėjo 21 d. Tyrimo metu identifikuotos 35 zooplanktono rūšys, priklausančios Rotatoria, Cladocera ir Copepoda grupėms. Dominavo Rotatoria grupės zooplanktonas (18 rūšių). 16 rūšių priklausė Cladocera grupei, 1 rūšis ir 1 gentis – Copepoda grupei. Visose mėginių ėmimo vietose dominavo šios rūšys: Polyarthra vulgaris, Asplanchna priodonta, Keratella cochlearis, Conochilus hippocrepis, Kellicottia longispina ir Gastropus stylifer (Rotatoria), Daphnia cucullata, Bosmina crassicornis, Ceriodaphnia affinis ir Diaphanosoma brachyurum (Cladocera), taip pat Cyclops sp. ir Eudiaptomus graciloides (Copepoda).

Keywords:

• Lake Svente
• zooplankton
• Rotatoria
• Cladocera
• Copepoda
• Renkonen index
• Shannon–Wiener index

Acknowledgements

The authors would like to thank Jana Paidere, MSc in biol., for her help in identifying plankton and for comments on the manuscript. The research was supported by the European Social Fund Project Formation of Interdisciplinary Research Group for Securing the Sustainability of Salmonid Lakes in Latvia No 2009/0214/1DP/1.1.1.2.0/09/APIA/VIAA/089.