Fine sediment deposition and interstitial flow effects on macroinvertebrate community composition within riffle heads and tails

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• 作者：Kate L. Mathers ; Paul J. Wood
• 刊名：Hydrobiologia
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：776
• 期：1
• 页码：147-160
• 全文大小：966 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Hydrobiology
  Ecology
  
• 出版者：Springer Netherlands
• ISSN：1573-5117
• 卷排序：776

文摘

The distribution of macroinvertebrates in the heads and tails of riffles were examined in an in situ field experiment under stable baseflow conditions. Paired colonisation cylinders were used to examine the influence of vertical hydraulic exchange (upwelling and downwelling) and horizontal interstitial flow on the patterns of sedimentation and invertebrate colonisation. Sedimentation rates were greatest in cylinders permitting vertical and horizontal flow (VHE cylinders), and were significantly lower (29%) in cylinders where only vertical flow and ingress of fine sediment were possible (VE cylinders). The results demonstrate that horizontal interstitial flows represent an important pathway for fine sediment transport. Differences in fine sediment accumulation were also observed between riffle heads and tails. Significantly higher sedimentation rates were recorded in riffle tails, with the macroinvertebrate communities characterised by larger proportions of fine sediment tolerant taxa. In contrast, riffle head communities were characterised by greater proportions of sediment sensitive taxa, and in the case of VHE cylinders, shredders and EPT taxa. The results demonstrate that spatial differences in fine sediment deposition are evident at the riffle scale as a function of vertical and horizontal subsurface flows and that these factors play a key role in the distribution of macroinvertebrate fauna.KeywordsHydrological exchangeUpwelling and downwelling waterInvertebrateHyporheic zoneSediment trapsInfiltration rates