Identification and Measure of Hydromorphological Degradation in Central European Lowland Streams

Abstract

The objective of the current study was to identify hydromorphological variables that are suitable to define and describe hydromorphological degradation. Stream type-specific and spatial scale-dependent multivariate analysis (Non-metric Multidimensional Scaling, NMS) of 106 hydromorphological variables derived from 275 samples at 147 sites and indicator value analysis (IndVal) resulted in the identification of key factors describing hydromorphological differences in Central European lowland streams. Sample sites represented six European stream types from Sweden (1 stream type), The Netherlands (2 stream types), and Germany (3 stream types). The four large-scale hydro(geo)morphological variables: catchment size, geology (`% moraines', `% alluvial deposits'), and natural land use (`% natural forest') explained inter-stream type differences best. On the smaller site scale, riparian vegetation described inter-stream type differences best.