Hydro-ecological variability within a groundwater dominated stream

Changes in the macroinvertebrate community in response to flow variations were examined over a six year period (1992-1997) in the Little Stour River, Kent, UK. This period included the final year of the 1988-1992 drought, followed by some of the wettest conditions recorded this century and a second period of drought between 1996 and 1997. Each year, samples were collected from 15 sites during summer baseflow conditions. Correspondence analysis identified clear differences between samples from upstream and downstream sites, and between drought and non-drought years. Stepwise multiple regression was used to identify hydrological indicators of community variation. High flows (or their absence), 4-7 months prior to sampling (i.e. winter-spring), were found to be the most important variables for describing the summer, low-flow community.