Long-term nutrient enrichment decouples predator and prey production
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Proceedings of the National Academy of Sciences. 107(1): 121-126.
Increased nutrient mobilization by human activities represents one of the greatest threats to global ecosystems, but its effects on ecosystemproductivity can differ depending on food web structure. When this structure facilitates efficient energy transfers to higher trophic levels, evidence from previous large-scale enrichments suggests that nutrients can stimulate the production of multiple trophic levels. Here we report results from a 5-year continuous nutrient enrichment of a forested stream that increased primary consumer production, but not predator production. Because of strong positive correlations between predator and prey production (evidence of highly efficient trophic transfers) under reference conditions, we originally predicted that nutrient enrichment would stimulate energy flow to higher trophic levels. However, enrichment decoupled this strong positive correlation and produced a nonlinear relationship between predator and prey production.
Keywordsecosystem enrichment; energy flow; food web efficiency; predator resistance; body size
Davis, John M.; Rosemond, Amy D.; Eggert, Susan L.; Cross, Wyatt F.; Wallace, J. Bruce. 2010. Long-term nutrient enrichment decouples predator and prey production