Is the hyporheic zone a refugium for macroinvertebrates during severe low flow conditions?

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Wood, P.J., Boulton, A.J., Little, S. ORCID: 0000-0001-5715-7429 and Stubbington, R. ORCID: 0000-0001-8475-5109, 2010. Is the hyporheic zone a refugium for macroinvertebrates during severe low flow conditions? Fundamental and Applied Limnology / Archiv für Hydrobiologie, 176 (4), pp. 377-390. ISSN 1863-9135

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Official URL: http://dx.doi.org/10.1127/1863-9135/2010/0176-0377

Abstract

The potential role of the hyporheic zone as a refugium for stream invertebrates during hydrological perturbations was acknowledged more than five decades ago. However, field evidence to support the hyporheic refuge hypothesis during periods of flow recession and severe low flow remains equivocal. Some studies report fauna using the hyporheic zone during periods of flow cessation whilst others have recorded little or no refuge use due to limited habitat availability or harsh abiotic conditions. We assessed aquatic macroinvertebrate community changes associated with severe low flow conditions during a severe supra-seasonal drought on the Little Stour River (UK). Paired benthic and hyporheic samples were collected from four sites (two perennial, two intermittent) on the upper reaches of the river. The number of benthic taxa and the proportion of benthos (particularly the amphipod Gammarus pulex ) within the hyporheic zone relative to those in the benthic samples increased signifi cantly during the latter stages of the drought at all sites. These changes coincided with elevated benthic and hyporheic water temperatures rather than a reduction in river discharge alone. The abundance of obligate hypogean macroinvertebrates also increased during the latter stages of the event, suggesting that hypogean taxa may also utilise the shallow hyporheic zone during adverse environmental conditions. Our results, based on paired surface-hyporheic field samples at multiple sites, support the hyporheic refuge hypothesis within a temperate groundwater-dominated stream during severe drought. The results also clearly demonstrate the importance of considering surface-subsurface linkages when assessing responses to disturbance in streams.

Item Type:

Journal article

Publication Title:

Fundamental and Applied Limnology / Archiv für Hydrobiologie

Creators:

Wood, P.J., Boulton, A.J., Little, S. and Stubbington, R.

Publisher:

E. Schweizerbart'sche Verlagsbuchhandlung

Date:

1 April 2010

Volume:

176