Projected novel eco-hydrological river types for Europe

Climate change and human use of water abstracted from rivers and groundwater are projected to alter river flow regimes worldwide in coming decades. Consequently, community structure in many rivers is expected to change because river flow is fundamental in determining conditions required by organisms, and processes on which they depend. Future flows in pan-European rivers were computed for baseline conditions (period 1961-1990) and for different combinations of climate and socio-economic scenarios (2040-2069). For each scenario a set of indicators was produced describing flow regime aspects that are most important in determining river ecosystem character. Classification techniques were applied to each set to define eco-hydrological river types. Spatial patterns of baseline and future types were mapped. Depending on scenario, about 30-50% of the river network length remained of the same type, whilst c. 40-50% transformed to an existing type; a third group of rivers (c. 10-20% of network length) formed new types, not present under baseline conditions, with potential to create novel river ecosystems.