2022 Early Hearing Detection & Intervention Virtual Conference
March 13 - 15, 2022
5/20/2019 | 11:30 AM - 11:45 AM | UNRAVELLING THE IMPACTS OF DROUGHT, NUTRIENT ENRICHMENT AND RIPARIAN CANOPY REMOVAL ON STREAM ECOSYSTEMS –A MESOCOSM APPROACH | 251 DE
UNRAVELLING THE IMPACTS OF DROUGHT, NUTRIENT ENRICHMENT AND RIPARIAN CANOPY REMOVAL ON STREAM ECOSYSTEMS –A MESOCOSM APPROACH
Agriculture and forestry degrade stream ecosystems by removing the riparian canopy and by intensifying nutrient runoff. In addition, catchment modification, hydropower and global warming are expected to alter the hydrological regime of boreal rivers, causing drought periods of varying duration and severity. While the individual impacts of these three stressors on stream ecosystems are well-addressed, their combined effects remain poorly understood. We assessed the individual and combined impacts of these stressors on the structure (invertebrates, diatoms, microbes) and functioning (algal production, organic matter decomposition) of stream ecosystems by experimentally manipulating nutrient enrichment, canopy removal and drought (pulse vs. press disturbance) in near-natural stream mesocosms. Drought predominantly altered the taxonomic composition of each group and the impact persisted even after a 3-week recovery period. The impacts of nutrients and canopy removal were weaker and taxa-specific. Drought suppressed algal productivity and the following recovery was aided by nutrients. Microbe- and invertebrate-mediated decomposition rates were amplified mainly by nutrients, with drought having additive positive effects on decomposition rates. Our study demonstrates that short-term drought has far-reaching impacts on stream biota and accelerates, together with nutrient enrichment, the key ecosystem processes of stream ecosystems.
- Mesocosm
- Decomposition
- Bacteria
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Presenters/Authors
Jussi Jyväsjärvi
(), Ecology and Genetics Research Unit, University of Oulu, Finland, jussi.jyvasjarvi@oulu.fi;
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Emma Göthe
(), County Administrative Board of Sweden, emma.gothe@lansstyrelsen.se;
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Kaisa Lehosmaa
(), Ecology and Genetics Research Unit, University of Oulu, Finland, kaisa.lehosmaa@oulu.fi;
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Anette Teittinen
(), Department of Geosciences and Geography, University of Helsinki, Finland , anette.teittinen@helsinki.fi;
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Janne Soininen
(), Department of Geosciences and Geography, University of Helsinki, Finland , janne.soininen@helsinki.fi;
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Ari Huusko
(), Natural Resources Institute Finland, ari.huusko@luke.fi;
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Timo Muotka
(), Ecology and Genetics Research Unit, University of Oulu, Finland, timo.muotka@oulu.fi;
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Brendan McKie
(), Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden, brendan.mckie@slu.se;
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