Zooplankton and fish community structures in interconnected lakes

Abstract

The aim of this study was to assess the species composition and structure of zooplankton and fish communities in lakes with similar ecological conditions that are connected by periodic streams. This was done by assessing the relative importance of local biotic and abiotic interactions associated with the species composition and structure of the zooplankton and fish communities. The study was conducted in three small, soft water lobelia lakes located in the source area of the Brda River, which were characterized by low trophic statuses and similar depths. A total of 15 Rotifera taxa, 18 Cladocera taxa, and nine Copepoda taxa were identified in the lakes analyzed. The lake zooplankton communities differed in species richness, total density, and biomass, while the Shannon–Wiener diversity indexes of the zooplankton communities were similar. Of the three lakes analyzed, the faunal similarity index was the highest in Lake Smołowe. Comparisons of the three lakes indicated there was greater similarity in the pelagic (42.7–50.0%) than in the littoral (20.1–26.8%) zones. The fish community of the three lakes consisted of eight species, and species richness ranged from two to eight fish species. Only perch (Perca fluviatilis L.) and pike (Esox lucius L.) were present in all three lakes. The fish groups also differed in terms of density and biodiversity indicators. Faunal similarity indicators showed significant similarity in the dominance structure of the fish communities.

Keywords

• connectivity
• isolation
• lobelia
• soft water lake
• fish predation