Modifying the PEG model for Mediterranean lakes – no biological winter and strong fish predation

Abstract

Summary The widely cited Plankton Ecology Group (PEG) model of plankton seasonal succession is often used as a template to explain the seasonal changes in plankton communities outside the cold temperate zone, where it was developed, but this may be inappropriate for lower‐latitude lakes. Lower‐latitude lakes have high light availability in winter and less pronounced seasonal variations in fish predation on zooplankton. We might therefore expect higher phytoplankton crops in winter and much more predation on zooplankton by fish than in colder lakes. This might lead to less grazing in summer and relatively higher phytoplankton crops. We compared data on phytoplankton biovolume, zooplankton biomass and body size from 18 German and 6 Greek lakes to test these hypotheses.