Summer is in winter: Disturbance-driven shifts in macroinvertebrate communities following hydroelectric power exploitation

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Document(s) secondaire(s)
Télécharger: Stoten_preprint.pdf (410.93 [Ko])
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Télécharger: Stoten_preprint.pdf (410.93 [Ko])
Etat: Public
Version: de l'auteur
ID Serval
serval:BIB_188D634CBB05
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Summer is in winter: Disturbance-driven shifts in macroinvertebrate communities following hydroelectric power exploitation
Périodique
Science of the Total Environment
Auteur(s)
Gabbud C., Lane S. N., Robinson C. T.
ISSN
0048-9697
ISSN-L
1879-1026
Statut éditorial
Publié
Date de publication
01/10/2018
Peer-reviewed
Oui
Volume
650
Pages
2164-2180
Langue
anglais
Résumé
In Alpine streams, humans have strongly modified the interactions between hydraulic processes, geomorphology and aquatic life through dams, flow abstraction at water intakes and river channel engineering. To mitigate these impacts, research has addressed both minimum flows and flow variability to sustain aquatic ecosystems. Whilst such environmental flows might work downstream of dams, this may not be the case for water intakes. Intakes, generally much smaller than dams, are designed to abstract water and to leave sediment behind. Sediment accumulation then results in the need to flush intakes periodically, often more frequently than daily in some highly glaciated basins. Sediment delivery downstream is then maintained through short duration floods with very high sediment loads. Here we tested the hypothesis that sediment flushing, and the associated high frequency of bed disturbance, controls in-stream habitat and macroinvertebrate assemblages. We collected macroinvertebrates over a 17-month period from an Alpine stream as well as a set of lateral unperturbed tributaries that served as controls. In contrast to established conceptual models, our results showed that the stream is largely void of life during summer, but that populations recover rapidly as the frequency of intake flushing falls in early autumn, producing richer and larger populations in winter and early spring. The recovery in autumn may be due to the recruitment of individuals from tributaries. We conclude that intake flushing in summer inverts expected summer-winter macroinvertebrate abundances, and questions the extent to which environmental flows in intake-impacted Alpine streams will lead to improvements in instream macrofauna unless sediment also is managed.
Mots-clé
Alpine stream, Water intake, Flushing, Macroinvertebrates, Environmental flows, Sediment
Open Access
Oui
Création de la notice
03/10/2018 11:09
Dernière modification de la notice
20/08/2019 13:49
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