Structure of plankton and waterbird communities under water level fluctuations: two case studies in shallow lakes of the Patagonian steppe

MARÍA SOL, PORCEL; FRANCISCO, SAAD JUAN; SABIO Y GARCÍA, CARMEN; SARACENO MARTÍN; MARINONE, M CRISTINA; FASOLA, LAURA; IGNACIO, ROESLER; JULIO L. LANCELOTTI; IRINA IZAGUIRRE

AQUATIC SCIENCES

BIRKHAUSER VERLAG AG

Lugar: BASEL; Año: 2024

1015-1621

The Strobel Lake Plateau (Patagonia, Argentina) holds natural fishless lakes that are the breeding habitat of many waterbird species, including threatened species. Fish introduction in some of these lakes have affected the structure of their zooplankton, phytoplankton and autotrophic picoplankton communities. Because bacterioplankton plays an important role in nutrient cycling and energy flow, we analyzed bacteria community diversity to assess the potential effect of fish introduction on this community in lakes of the Strobel Plateau. We sampled fishless and fish stocked lakes during three summer campaigns and analyzed the bacterioplankton community composition (BCC). Our results revealed a contrasting arrangement in the main limnological variables and significant differences in the BCC between fishless and stocked lakes. In fish stocked lakes, Alphaproteobacteria class had a higher proportion and SAR11_cladeIII was the most abundant amplicon sequence variant (ASV); this group of lakes showed also a marginally higher mean richness but less exclusive ASVs. Environmental factors, including fish presence, and zooplankton functional group richness contributed to explain BCC variations. The lower percentage of exclusive ASVs and the closer BCC ordination in a non-metric multidimensional scaling for stocked lakes, suggest a homogenizing effect in this group of lakes. This study contributes to understand the consequences of fish introduction on the plankton communities in lakes of this invaluable region for biodiversity conservation.