Detritivore stoichiometric diversity alters litter processing efficiency in a freshwater ecosystem |
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| Authors: | Tamihisa Ohta Sou Matsunaga Shigeru Niwa Kimitaka Kawamura Tsutom Hiura |
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| Affiliation: | 1. Tomakomai Research Station, Field Science Center for Northern Biosphere, Hokkaido University, Hokkaido, Japan;2. Graduate School of Environmental Science, Hokkaido University, Sapporo, Japan;3. Network Center of Forest and Grassland Survey in Monitoring Sites 1000 Project, Japan Wildlife Research Center, Hokkaido, Japan;4. Inst. of Low Temperature Science, Hokkaido University, Sapporo, Japan |
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| Abstract: | Many studies have estimated relationships between biodiversity and ecosystem functioning, and observed generally positive effects. Because detritus is a major food resource in stream ecosystems, decomposition of leaf litter is an important ecosystem process and many studies report the full range of positive, negative and no effects of diversity on decomposition. However, the mechanisms underlying decomposition processes in fresh water remain poorly understood. Organism body stoichiometry relates to consumption rates and tendencies, and decomposition processes of litter may therefore be affected by diversity in detritivore body stoichiometry. We predicted that the stoichiometric diversity of detritivores (differences in C: nutrient ratios among species) would increase the litter processing efficiency (litter mass loss per total capita metabolic capacity) in fresh water through complementation regarding different nutrient requirements. To test this prediction, we conducted a microcosm experiment wherein we manipulated the stoichiometric diversity of detritivores and quantified mass loss of leaf litter mixtures. We compared litter processing efficiency among litter species in each microcosm with single species detritivores, and observed detritivores with nutrient‐rich bodies tended to prefer litter with lower C: nutrient ratios over litter with higher C: nutrient ratios. Furthermore, litter processing efficiencies were significantly higher in the microcosms containing species of detritivores with both nutrient‐rich and ‐poor bodies than microcosms containing species of detritivores including only nutrient‐rich or ‐poor bodies. This might mean a higher stoichiometric diversity of detritivores increased litter processing efficiency. Our results suggest that ecological stoichiometry may improve understanding of links between biodiversity and ecosystem function in freshwater ecosystems. |
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