Synergistic impacts of sediment contamination and dam presence on river functioning
| Autor: | Simon Devin, Michael Danger, Fanny Colas, Jean-Marc Baudoin, Philippe Usseglio-Polatera, Philippe Wagner |
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| Rok vydání: | 2012 |
| Předmět: |
0106 biological sciences
Ecosystem health Ecology 010604 marine biology & hydrobiology Ecological assessment Context (language use) Asexual reproduction 010501 environmental sciences 15. Life on land Aquatic Science Contamination Plant litter 01 natural sciences 6. Clean water Current (stream) 13. Climate action Environmental science 0105 earth and related environmental sciences Invertebrate |
| Zdroj: | Freshwater Biology. 58:320-336 |
| ISSN: | 0046-5070 |
| DOI: | 10.1111/fwb.12060 |
| Popis: | Summary 1. Dam presence is commonly associated with strong accumulation of polluted sediments. In spite of this context of multiple stressors, physical effects are often solely considered in the ecological assessment of the dam impacts. 2. We studied four ‘reservoir/downstream reach’ systems differing in levels of sediment contamination in reservoirs. Using assemblages and biotrait (i.e. ecological or biological attribute) responses of macroinvertebrate communities and leaf litter breakdown, we examined the individual effects and potential interactions between sediment contamination and dam presence along the gradient of ecotoxic pressure. 3. Leaf breakdown rates ranged from 0.0044° per day in the most contaminated reservoir to 0.0120° per day in the reference reservoir. Comparisons of community trait profiles among reservoirs highlighted a gradient of trait responses to sediment contamination. 4. In the absence of toxic contamination, the dam-induced modifications in biotraits of invertebrate assemblages were not related to a reduction of leaf litter breakdown. Conversely, contaminated sediment in reservoir induced strong functional disturbances (i.e. bioecological shifts and reduction of leaf litter breakdown) downstream of dams. 5. Key biotrait categories positively related to leaf litter breakdown rate have been identified. They corresponded mainly to shredders and/or small-sized ( 4 cm) species, having several generations per year (polyvoltin), using asexual reproduction and/or disseminating by drift (aquatic, passive). 6. In the current context of ecological continuity restoration, this study has identified the risks associated with the presence of historical contamination in the run-of-river reservoirs for downstream ecosystem health. |
| Databáze: | OpenAIRE |
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