2023 Early Hearing Detection & Intervention Conference
March 5-7, 2023 • Cincinnati, OH
5/22/2018 | 2:15 PM - 2:30 PM | STREAM COMMUNITIES EXCEED ECOLOGICAL THRESHOLDS DUE TO DROUGHT INTENSIFICATION: EVIDENCE FROM A LARGE SCALE MESOCOSM EXPERIMENT | 410 A
STREAM COMMUNITIES EXCEED ECOLOGICAL THRESHOLDS DUE TO DROUGHT INTENSIFICATION: EVIDENCE FROM A LARGE SCALE MESOCOSM EXPERIMENT
Droughts are predicted to intensify in the future, potentially causing many running waters to exceed key ecological thresholds. The effects of these events have not been assessed directly because the required continuous drought disturbance gradient is rarely encountered in natural streams. To address this research gap we established a highly resolved, drought intensity gradient using large, once through, mesocosm channels enabling macroinvertebrate community response to be quantified. Threshold changes were detected for >60% of the most abundant invertebrate taxa, with sudden population crashes or irruptions in response to increased drought intensity. Step-changes were most pronounced at moderate drought (~50% wetted area remaining); predatory midge larvae irrupted as channels fragmented into isolated pools, with corresponding collapses in prey populations. These findings, highlight the sensitivity of predatory-prey dynamics to drought, especially for the smaller body size classes as opposed to just the larger taxa as typically assumed. These findings suggest drought transforms fundamental food web properties (i.e. predator: prey ratios and community size structure) long before complete surface water loss. Hence, river ecosystems are likely to be particularly sensitive to future changes in precipitation patterns and population driven abstraction demands.
- Climate Change
- Mesocosm
- Invertebrate
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Presenters/Authors
Thomas Aspin
(), Univerisity of Birmingham, TWA436@student.bham.ac.uk;
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Kieran Khamis
(), University of Birmingham, k.khamis@bham.ac.uk;
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Victoria Milner
(), University of Worcester, v.milner@worc.ac.uk;
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Mark Trimmer
(), Queen Mary University of London, mtrimmer@qmw.ac.uk;
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Guy Woodward
(), Imperial College London, gu.woodward@imperial.ac.uk;
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Mark Ledger
(), University of Birmingham, m.e.ledger@bham.ac.uk;
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