Resource quality and stoichiometric constraints on stream ecosystem functioning

• DOI: 10.1111/j.1365-2427.2008.02138.x
• Publication Date: 2008-11-11T01:19:14Z
• Authors: SALLY HLADYZ; MARK O. GESSNER; PAUL S. GILLER; JEŚUS POZO; GUY WOODWARD
• Keywords: Decomposer; Ecological stoichiometry; Detritivore; Litter; Plant litter; Nutrient cycle; Palatability; Detritus

Summary 1. Resource quality and stoichiometric imbalances in carbon : nutrient ratios between consumers resources can influence key ecosystem processes. In many streams, this has important implications for food webs that are based largely upon the utilization of terrestrial leaf‐litter, which varies widely among litter types its value as a source detritivores substrate microbial decomposers. 2. We measured breakdown rates macroinvertebrate colonization leaf‐litter from range native exotic plants differing resource palatability to [e.g. nitrogen phosphorus (C N P) ratios, lignin cellulose content], field experiment. also C P principal leaf‐shredding invertebrates, revealed strong across trophic levels: typically differed by at least one order magnitude resources, whereas were less marked. Application threshold elemental ratio approach, integrates animal bioenergetics body composition examining deficiency marked than those on simpler arithmetic differences described above. 3. Litter declined widened fell, but they independent whether or native. The drivers total, invertebrate‐mediated N, fungal biomass, respectively. However, multiple regression using orthogonal predictors yielded even more efficient models breakdown, responded aspect quality. For example, biomass both influenced breakdown. 4. Large changes likely have serious consequences stream functioning, especially when riparian zones been invaded plant species whose chemical differs markedly flora. Consequently, direction change and, thus, depletion, will be driven large extent biochemical traits (rather taxonomic identity per se ) resident invading