COLONIZATION AND SUCCESSION OF ZOOPLANKTON AFTER DROUGHT IN A FLOODPLAIN LAKE: INFLUENCE OF HYDROLOGY AND MACROPHYTE DYNAMICS

CHAPARRO G.; FONTANARROSA M.S.; O'FARRELL I.

Granada

Congreso; AQUATIC SCIENCES: GLOBAL AND REGIONAL PERSPECTIVES ? NORTH MEETS SOUTH; 2015

We analysed the temporal and spatial dynamics of zooplankton succession after a drought in relation to environmental factors in different vegetated and non-vegetated habitats from a South American floodplain lake. We found similar temporal patterns of broad taxonomic zooplankton groups, irrespective to habitats. In the filling phase that occurred in early autumn, rotifers and cyclopoid copepod colonizers were replaced by cladocerans towards the end of winter. Later on, the occurrence of floods in spring and summer determined a high water phase with free-floating plants dominance, low zooplankton biomass and high species richness mainly composed of littoral rotifers. Spatial and temporal patterns of species composition were closely linked to the dynamics of free-floating plants, while the presence of emergent plants seemed to be irrelevant. A clear shift from pelagic to littoral taxa dominance in habitats or periods where free-floating plants were present was registered. The high species turnover over the 18 months included in this study reveals the highly disturbed nature of floodplain lakes, with hydrology and free-floating plants as main driving factors for zooplankton succession