Author(s): Kate Mathers; Morwenna Mckenzie; Paul Wood

Linked Author(s):

Keywords: Colmation; Subsurface sediments; Patchiness; Grain size distribution; Clogging

Abstract: Understanding the mechanisms that structure riverine ecological communities is essential for advancing research, guiding management, and informing monitoring strategies. While previous studies have predominantly emphasized the influence of surface habitat characteristics in benthic ecology, subsurface hyporheic habitats have received comparatively less attention. This study investigates how reach-scale benthic substrate composition, categorized as fine, moderate, or coarse substrate composition, influences hyporheic physicochemical conditions and macroinvertebrate communities across twenty stream sites in England and Wales. Results indicate that distinct benthic substrates are associated with significantly different hyporheic environmental conditions and community assemblages. Despite marked variation in benthic surface composition, hyporheic substrate grain size distributions remained similar across sites. These findings indicate that, under stable and low-flow conditions, the composition of surface substrates at the reach scale can exert a control on subsurface ecological and physicochemical dynamics.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.130

Year: 2026