Regime shifts in a shallow lake: Consequences for taxonomic and functional diversity, and ecosystem multifunctionality

Under increasing nutrient loading, shallow lakes may shift from a state of clear water dominated by submerged macrophytes to a turbid state dominated by phytoplankton or a shaded state dominated by floating macrophytes. How such regime shifts mediate the relationship between taxonomic and functional diversity and lake multifunctionality is poorly understood.
We employed a detailed database describing a shallow lake over a 12-year period during which the lake has displayed all the three states (clear, turbid, and shaded) to investigate how species richness, functional diversity of fish and zooplankton, ecosystem multifunctionality, and five individual ecosystem functions (nitrogen and phosphorus concentrations, standing fish biomass, algae production, and light availability) differ among states. We also evaluated how the relationship between biodiversity (species richness and functional diversity) and multifunctionality is affected by regime shifts.
We showed that species richness...