| 1. |
- Frainer, André, et al.
(författare)
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No evidence for leaf-trait dissimilarity effects on litter decomposition, fungal decomposers, and nutrient dynamics
- 2015
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Ingår i: Ecology. - : Ecological Society of America. - 0012-9658 .- 1939-9170. ; 96:2, s. 550-561
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Tidskriftsartikel (refereegranskat)abstract
- Biodiversity and ecosystem-functioning theory suggest that litter mixtures composed of dissimilar leaf species can enhance decomposition due to species trait complementarity. Here we created a continuous gradient of litter chemistry trait variability within species mixtures to assess effects of litter dissimilarity on three related processes in a natural stream: litter decomposition, fungal biomass accrual in the litter, and nitrogen and phosphorus immobilization. Litter from a pool of eight leaf species was analyzed for chemistry traits affecting decomposition (lignin, nitrogen, and phosphorus) and assembled in all of the 28 possible two-species combinations. Litter dissimilarity was characterized in terms of a range of trait-diversity measures, using Euclidean and Gower distances and dendrogram-based indices. We found large differences in decomposition rates among leaf species, but no significant relationships between decomposition rate of individual leaf species and litter trait dissimilarity, irrespective of whether decomposition was mediated by microbes alone or by both microbes and litter-consuming invertebrates. Likewise, no effects of trait dissimilarity emerged on either fungal biomass accrual or changes during decomposition of nitrogen or phosphorus concentrations in individual leaf species. In line with recent meta-analyses, these results provide support for the contention that litter diversity effects on decomposition, at least in streams, are less pronounced than effects on terrestrial primary productivity.
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| 2. |
- Frainer, André, et al.
(författare)
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Shifts in the Diversity and Composition of Consumer Traits Constrain the Effects of Land Use on Stream Ecosystem Functioning
- 2015
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Ingår i: Advances in Ecological Research. - : Elsevier. - 0065-2504. ; 52, s. 169-200, s. 169-200
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Forskningsöversikt (refereegranskat)abstract
- Species functional traits provide an important conceptual link between the effects of disturbances on community composition and diversity, and their ultimate outcomes for ecosystem functioning. Across 10 boreal streams covering a gradient of increasing intensity of land-use management, from forested to agricultural sites, we analysed relationships between leaf decomposition, the feeding traits of detritivores and measures of anthropogenic disturbances in two seasons. The direct effect of increasing land-use intensity on decomposition was positive and was associated with increases in nutrient concentrations and current velocities. However, this relationship was countered by negative effects associated with a loss of detritivore functional diversity along the gradient during autumn and shifts in species trait composition during spring, limiting the net change in functioning associated with increasing land-use management overall. Our results highlight the key roles that trait identity and diversity can play in mediating the effects of human disturbance on ecosystem functioning.
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