Adaptive responses of freshwater pearl mussels, Margaritifera margaritifera, to managed drawdowns

Curley, E. A.M. , Thomas, R. , Adams, C. E. and Stephen, A. (2022) Adaptive responses of freshwater pearl mussels, Margaritifera margaritifera, to managed drawdowns. Aquatic Conservation: Marine and Freshwater Ecosystems, 32(3), pp. 466-483. (doi: 10.1002/aqc.3759)

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1. Alterations to water management practices, in response to a growing demand to maximize energy production from renewable sources, threaten to exacerbate anticipated future water shortages caused by severe drought episodes, brought on by climate change. 2. Across Scotland, many highly managed systems are inhabited by some of the last remaining reproductively viable populations of the freshwater pearl mussel, Margaritifera margaritifera. A lack of empirical evidence concerning mussel responses to alterations in flow is inhibiting the development of effective conservation management practices to prolonged drought. 3. This study addressed this knowledge gap by examining the response of M. margaritifera to controlled water level drawdowns in laboratory and field settings. Using a laboratory flume, the responses of M. margaritifera from two different populations (a regulated system versus an unregulated system) were compared across rates of drawdown and density treatments. An analogous field trial was undertaken to examine the responses of M. margaritifera in a regulated system, with a hydroelectric dam facilitating a controlled drawdown. 4. The study showed that M. margaritifera can detect alterations in flow depth, which culminate in the emersion of mussel beds, and respond by undertaking vertical and horizontal movements to mitigate the risk of prolonged aerial exposure. Results from the field trial corroborated findings from the flume experiments, with 80% of mussels shown to avoid emersion successfully by tracking receding water levels. 5. Findings from this study support the role of controlled drawdowns in regulated rivers to reduce mortalities associated with receding water levels during prolonged low-flow episodes. Differences between populations in response highlight a need to adopt a context-dependent approach to conservation efforts.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Thomas, Dr Rhian and Curley, Dr Edward and Adams, Professor Colin
Authors: Curley, E. A.M., Thomas, R., Adams, C. E., and Stephen, A.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
College of Social Sciences > School of Interdisciplinary Studies
College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Aquatic Conservation: Marine and Freshwater Ecosystems
ISSN (Online):1099-0755
Published Online:03 December 2021
Copyright Holders:Copyright © 2021 The Authors
First Published:First published in Aquatic Conservation: Marine and Freshwater Ecosystems 32(3): 466-483
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
173130Investigating the impact of hydrodynamics on the behaviour of the endangered freshwater pearl mussel using field and laboratory approachesRhian ThomasNatural Environment Research Council (NERC)NE/N007743/1GES - Geography