Different intensities and directions of hyporheic water exchange in habitats of aquatic Ranunculus species in rivers-a case study in Poland.

Hyporheic water exchange driven by groundwater-surface water interactions constitutes habitat conditions for aquatic biota. In our study, we conducted a field-research-based analysis of hyporheic water exchange to reveal whether the hyporheic water exchange differentiates particular Ranunculus sp. habitats. We measured the density of the stream of upwelling and hydraulic gradients of water residing in the hyporheic zone in 19 Polish rivers. We revealed that R. peltatus and R. penicillatus persist in habitats of considerably higher hyporheic water exchange upwelling flux (respectively 0.0852 m 3 ∙d -1 ∙m -2 and 0.0952 m 3 ∙d -1 ∙m -2 ) than R. circinatus, R. fluitans, and a hybrid of R. circinatus × R. fluitans (respectively m 3 ∙d -1 ∙m -2 ; 0.0222 m 3 ∙d -1 ∙m -2 and 0.0717 m 3 ∙d -1 ∙m -2 ). The presented results can be used to indicate aquatic habitat suitability in the case of protection and management of ecosystems settled by Ranunculus sp.