Assessment of climate change effect on environmental flows for macroinvertebrates using an integrated hydrological-hydraulic-habitat modelling

Abstract

Study region: A short reach of the Jeziorka river and its upstream catchment in central Poland Study focus: Climate change is expected to have significant impacts on freshwater ecosystems, particularly on temperate region streams resulting often in changes to spatiotemporal distribution of macroinvertebrate species, as well as losses in richness and aquatic biodiversity due to the loss of suitable habitat. This study aimed to evaluate the impact of climate change on the habitat suitability and environmental flow violations for the filter feeder functional group of macroinvertebrate communities in a temperate lowland river in central Poland. To achieve this, we have successfully integrated hydrological (SWAT+), hydraulic (HEC-RAS 1D and SRH-2D), and habitat (CASiMiR) models. We have forced the model cascade with GCM/RCM projections to determine changes in future habitat conditions for a selected reach of the Jeziorka river. New hydrological insights for the region: Future habitat conditions may deteriorate, as reflected in overwhelmingly negative trends in the hydraulic habitat suitability (HHS) index. According to the projections, there will be fewer days with the necessary environmental flows for filter feeders in the future. The frequency and duration of environmental flow violations, caused by too low or too high flows, depend on the climate model scenarios and timeframes. Our findings will aid water resource planners in achieving sustainable water resource management and meeting environmental flow requirements in the face of a changing climate.

Keywords

• Climate change
• Filter feeders
• Ecohydrological modelling cascade
• Environmental flows