Mathers et al_Accepted.pdf (3.31 MB)

Faunal response to benthic and hyporheic sedimentation varies with direction of vertical hydrological exchange

Download (3.31 MB)
journal contribution
posted on 28.01.2015, 12:57 by Kate L. Mathers, Jonathan Millett, Anne L. Robertson, Rachel Stubbington, Paul J. Wood
Sedimentation and clogging of benthic and hyporheic zone substrata is increasingly being recognised as one of the greatest threats to the ecological integrity of riverine ecosystems globally. This ex situ study examined the influence of sedimentation (surface and subsurface) and pattern of hydrological exchange on the vertical distribution of the freshwater shrimp Gammarus pulex within the experimental substrata of running water mesocosms. Six sediment treatments representing a continuum from a clean gravel substratum to heavy sediment loading of both surface (benthic) and subsurface (hyporheic) substrata were used to examine the distribution of G. pulex in relation to the direction of hydrological exchange (downwelling, upwelling and no exchange). The distribution of G. pulex between the sediment layers was dependent on the pattern of hydrological exchange, sediment treatment and the interaction between these two factors. Sedimentation of the surface layer under no-exchange conditions resulted in a lower proportion of G. pulex being recorded in the benthic sediments, whilst there were no significant differences under downwelling and upwelling flow conditions. Sedimentation of multiple layers of the column (benthic and subsurface) reduced the ability of individuals to utilise the subsurface layers of the substratum (i.e. the hyporheic zone) under no-exchange and upwelling conditions. However, with downwelling conditions, the abundance of G. pulex declined with depth regardless of the fine sediment distribution or volume. This study demonstrates that faunal movement, and use of benthic and hyporheic substrata, may be influenced by sedimentation and modified by the pattern of vertical hydrological exchange. Severe sedimentation (colmation) has the potential to prevent benthic fauna from accessing the hyporheic zone and its resources which may ultimately lead to a reduction in stream diversity and metabolism, thereby limiting overall productivity and lotic ecosystem resilience.

Funding

KLM gratefully acknowledges the support of a Nuffield Undergraduate Research Bursary (URB/39419) to undertake the research entitled ‘The influence of fine sediment deposition and clogging on macroinvertebrate utilisation of benthic and hyporheic sediments’. PJW acknowledges the support of the British Cave Research Association Cave Science and Technology Research Initiative grant to develop the experimental hypogean laboratory.

History

School

  • Social Sciences

Department

  • Geography and Environment

Published in

Freshwater Biology

Volume

59

Issue

11

Pages

2278 - 2289

Citation

MATHERS, K.L. ... et al, 2014. Faunal response to benthic and hyporheic sedimentation varies with direction of vertical hydrological exchange. Freshwater Biology, 59 (11), pp.2278-2289.

Publisher

© John Wiley & Sons Ltd

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2014

Notes

This is the peer reviewed version of the following article: MATHERS, K.L. ... et al, 2014. Faunal response to benthic and hyporheic sedimentation varies with direction of vertical hydrological exchange. Freshwater Biology, 59 (11), pp.2278-2289, which has been published in final form at http://dx.doi.org/10.1111/fwb.12430. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.

ISSN

0046-5070

eISSN

1365-2427

Language

en

Exports