Are riverine lowland lakes a distinct European lake type according to the EU WFD?

Abstract

Riverine lakes are a distinct lake type found in geographic regions of Europe shaped by glacial processes. Knowledge concerning their macroinvertebrate communities is scarce and hampers the development of type-specific assessment methods as demanded by the European Union Water Framework Directive (WFD). We compared macroinvertebrate community composition between near-natural riverine lakes and three other types of near-natural lowland lakes to test if communities differ among types. Moreover, we quantified how macroinvertebrate communities from riverine lakes change along a degradation gradient as the basis for developing ecological status classes. Results showed that macroinvertebrate communities significantly differed between riverine and other lowland lake types. The indicator taxa characteristic for near-natural riverine lakes were significantly correlated with environmental characteristics, i.e., comparatively low maximum water depths and high %macrophyte and xylal habitats. Macroinvertebrate communities differed in their taxonomic composition between riverine lake degradation classes, with significant indicator taxa identified for these. We provided empirical evidence that riverine lakes harbour a distinct littoral macroinvertebrate community and recommend establishing riverine lakes as a separate lake type in the Central Plains ecoregion in national typologies for biotic assessments in compliance with the WFD.

Keywords

• Water residence time
• Macroinvertebrate community
• Hydromorphological degradation
• Lake typology
• European Union Water Framework Directive
• Riverine lakes