Instream mesohabitat biodiversity in three groundwater streams under base-flow conditions

Concerns regarding the ecological functioning and biodiversity of groundwater-dominated rivers have been highlighted in the wake of increased water resource pressures, channel management activities and natural drought. 2. The macroinvertebrate communities within three groundwater-dominated streams in the UK, subject to different management strategies, were examined in relation to substratum mesohabitat diversity. 3. The mesohabitat structure was similar at all three sites examined but the number of taxa present at each site varied markedly. 4. Differences found at each site are related to (i) recent hydrological conditions (drought severity) and (ii) management activities, and are discussed with reference to the conservation and restoration of riverine systems.