2 research outputs found
How freshwater biomonitoring tools vary subâseasonally reflects temporary river flow regimes
Characterizing temporary river ecosystem responses to flow regimes is vital for conserving their biodiversity and the services they provide to society. However, freshwater biomonitoring tools rarely reflect community responses to hydrological variations or flow cessation events, and those available have not been widely tested within temporary rivers. This study examines two invertebrate biomonitoring tools characterizing community responses to different flowârelated properties: the âDrought Effect of Habitat Loss on Invertebratesâ (DEHLI) and âLoticâinvertebrate Index for Flow Evaluationâ (LIFE), which, respectively reflect community responses to habitat and hydraulic properties associated with changing flow conditions. Subâseasonal (monthly) variations of LIFE and DEHLI were explored within two groundwaterâfed intermittent rivers, one dries sporadically (a flashy, karstic hydrologyâRiver Lathkill) and the other dries seasonally (a highly buffered flow regimeâSouth Winterbourne). Biomonitoring tools were highly sensitive to channel drying and also responded to reduced discharges in permanently flowing reaches. Biomonitoring tools captured ecological recovery patterns in the Lathkill following a supraâseasonal drought. Some unexpected results were observed in the South Winterbourne where LIFE and DEHLI indicated relatively highâflow conditions despite low discharges occurring during some summer months. This probably reflected macrophyte encroachment, which benefitted certain invertebrates (e.g., marginalâdwelling taxa) and highlights the importance of considering instream habitat conditions when interpreting flow regime influences on biomonitoring tools. Although LIFE and DEHLI were positively correlated, the latter responded more clearly to drying events, highlighting that communities respond strongly to the disconnection of instream habitats as flows recede. The results highlighted shortâterm ecological responses to hydrological variations and the value in adopting subâseasonal sampling strategies within temporary rivers. Findings from this study indicate the importance of establishing flow response guilds which group taxa that respond comparably to flow cessation events. Such information could be adopted within biomonitoring practices to better characterize temporary river ecosystem responses to hydrological variations