Print PageReservoirs are artificial systems that contain assemblages of colonizing, or introduced, species that have no evolutionary history within the systems. While the lacustrine zone of reservoirs broadly mimics natural lakes there are important differences, such as higher light extinction, more frequent disturbance, and greater influence of the watershed. As a result, reservoir communities are thought to be less diverse than natural lakes and comprised of tolerant species. My goal was to evaluate richness and community characteristics of phytoplankton across lakes and reservoirs. I compared phytoplankton collected from the upper epilimnion of 508 systems in the US for the National Lakes Assessment.
Results/Conclusions
Richness was similar in reservoirs relative to lakes of comparable size in northern latitudes, but slightly lower in southern reservoirs. Most genera that were widespread in northern lakes (occurred in at least 50% of lakes) also were widespread in northern reservoirs; however there were slight differences in the community in southern reservoirs relative to northern systems. For example, the diversity of chrysophyte and cryptomonad taxa was significantly lower in southern reservoirs. General phytoplankton community attributes in the upper epilimnion of reservoirs appear to be closer to those of lakes than previously thought, although further examination of functional groups and dominant species is warranted, particularly relative to climate.
