Synchrony of algal blooms in neighbouring lakes: connectivity or territoriality

The biological synchrony of neighbouring lakes in Central Europe was evaluated by analysing the concurrent time series of algal biomass variables using long-term (1999–2019) satellite (Landsat 7) derived chlorophyll-index data. The synchrony between the hydrologically connected and disconnected lakes was estimated and compared. Although the hydrologically connected lakes showed a low but significant synchrony (0.21 ± 0.07), the synchrony of phytoplankton phenological events in two hydrologically separated lakes was higher (0.50 ± 0.07). All data indicated a robust spatial correlation: the closer the compared lake regions were to each other, the higher the degree of similarity was. These data suggest that hydrological connectivity between lakes is not necessary and that the geological, geomorphological and mesoclimatic characteristics of the region may have a greater influence on the occurrence of biological processes in the lakes. Proximity of the lakes studied suggests that large-scale, integrating factors affecting all three studied lakes override the idiosyncrasies of these lakes, and therefore clustered management of neighbouring lakes may be useful to consider.