STOICHIOMETRY OF STANDARDIZED WOOD SUBSTRATES IS AN EFFECTIVE TOOL FOR DETECTING NUTRIENT POLLUTION IN STREAMS
Tools to detect negative effects of excess nutrients, nitrogen (N) and phosphorus (P), on detrital resources are needed for management. We tested the response of standardized detrital materials to landscape gradients in N and P to determine whether breakdown and respiration rates of labile (cellulose sponge) or recalcitrant (wood veneer) substrates increased with N or P. In a longer-term study, we tested whether detrital stoichiometry or streamwater nutrient concentrations was a better predictor of breakdown rates. We found that both respiration and breakdown rates of labile and recalcitrant substrates increased in short-term studies and responded more to P than N. In the longer-term study, streamwater P concentrations also greatly increased breakdown of wood veneers (4x over the P gradient we studied). Detrital nutrient content was a better predictor of mass loss than streamwater nutrient concentrations; carbon:N and carbon:P of detrital substrates explained 62% and 54% of mass loss, respectively. Our study reveals that standardized detrital substrates respond to gradients in nutrients in complex, human modified ecosystems and that stoichiometry of standardized wood substrates may be an effective and low-cost tool for detecting nutrient effects on an essential ecosystem function.
Phillip Bumpers (Primary Presenter/Author,Co-Presenter/Co-Author), Odum School of Ecology, University of Georgia, email@example.com;
Rachel Usher (Co-Presenter/Co-Author), University of Georgia, firstname.lastname@example.org;
Amy D. Rosemond (Co-Presenter/Co-Author), Odum School of Ecology, University of Georgia , email@example.com;
James Wood (Co-Presenter/Co-Author), West Liberty University, James.Wood@westliberty.edu;
Seth Wenger (Co-Presenter/Co-Author), Odum School of Ecology, University of Georgia, firstname.lastname@example.org;