Nutrient enrichment reduces constraints on material flows in a detritus-based food web.

摘要: Most aquatic and terrestrial ecosystems are experiencing increased nutrient availability, which is affecting their structure function. By altering community composition productivity of consumers, enrichment can indirectly cause changes in the pathways magnitude material flows food webs. These changes, turn, have major consequences for storage cycling ecosystem. Understanding mechanisms predicting nutrient-induced requires a quantitative web approach that combines information on consumer energetics consumer-resource stoichiometry. We examined effects whole-system experimental trophic basis production carbon (C), nitrogen (N), phosphorus (P) detritus-based stream web. compared response treated to an adjacent reference throughout study. Dietary elemental varied considerably among invertebrate functional feeding groups. During enrichment, leaf litter amorphous detritus shredders gatherers accounted most altered C from basal resources consumers. Nutrient had little effect patterns but large positive C, N, P consumers (mean increase 97% all elements). Nutrient-specific webs revealed similar N multiple groups despite order difference consumption C. Secondary was more strongly related nutrients than were positively degree C:P C:N imbalances. resulted proportion detrital inputs consumed by primary (from ;15% 35%) decreased prey predators ;80% 55%). Our results demonstrate systems may reduce stoichiometric constraints flows, contribution cycling, alter metabolized potentially lead reduced ecosystem-level