Tuesday, August 5, 2008 - 9:50 AM

COS 16-6: Aquatic insect emergence as a link between aquatic and terrestrial habitats: Comparison of streams and lakes

Claudio Gratton, University of Wisconsin - Madison and M. Jake Vander Zanden, University of Wisconsin-Madison.

Background/Question/Methods

Aquatic insect emergence represents one important way in which materials and energy can cross habitat boundaries to link aquatic and terrestrial systems. The magnitude and ecological implications of this flux have been examined for a number of streams, but not for lakes. Using a synthesis of empirically-derived data for lakes and streams, we estimate the magnitude of this aquatic-terrestrial linkage for streams and lakes. Insect production and emergence on a per-unit-area basis (gC m-2 yr-1) and ecosystem geometry are used to estimate aquatic production flux to land per meter of shoreline (gC m-1 yr-1) across gradients of stream and lake attributes. 

Results/Conclusions

Though streams exhibit higher rates of production and emergence, lakes appear to show higher fluxes to land primarily as a result of greater habitat area per unit shoreline relative to streams. Our analysis highlights some potential differences between aquatic-terrestrial linkages for lakes and streams, as well as the dual role of benthic productivity and ecosystem geometry in determining the flux and implications of aquatic productivity to the surrounding landscape.