More than one million barriers fragment Europe’s rivers

Rivers support some of earth’s richest biodiversity and provide essential services to society, but only if they flow. In Europe, attempts to quantify river connectivity, as required by the Water Framework Directive, have been hampered by lack of harmonised barrier records. We assembled 630,000 unique barrier records from 36 countries and surveyed 2,536 km in 128 European rivers revealing a ~100% barrier underestimation from existing records. We estimate that there are at least 1.2 million longitudinal instream barriers (mean density = 0.75 barrier/km), 72% of which are low-head (<2m) structures, making Europe the world’s most fragmented river landscape. The highest barrier densities are found in the heavily modified rivers of central Europe, and the lowest in the most remote, sparsely populated alpine areas. Barrier density was predicted by agricultural pressure, road density, elevation, and drainage density. Relatively unfragmented rivers are still found in the Balkans, Scandinavia, the headwaters of the Baltic States, and parts of Southern Europe, but require urgent protection from new dam developments. Our findings can inform the implementation of the new EU Biodiversity Strategy, which aims to reconnect 25,000 km of Europe’s rivers, but this will require a paradigm shift in river restoration that considers small barriers.

BELLETTI Barbara;  GARCIA DE LEANIZ Carlos;  JONES Josh;  BIZZI Simone;  BORGER Luca;  SEGURA Gilles;  CASTELLETTI Andrea;  VAN DE BUND Wouter;  AARESTRUP Kim;  BARRY James;  BELKA Kamila;  BERKHUYSEN Arjan;  BIRNIE-GAUVIN Kim;  BUSSETTINI M;  CAROLLI Mauro;  CONSUEGRA Sofia;  DOPICO Eduardo;  FEIERFELL Tim;  FERNANDEZ Sara;  FERNANDEZ GARRIDO Pao;  GARCIA-VAZQUEZ Eva;  GARRIDO Sara;  GIANNICO Guillermo;  GOUGH Peter;  JEPSEN N.;  JONES Peter;  KEMP Paul;  KERR Jim;  KING James;  LAPINSKA Malgorzata;  LAZARO Gloria;  LUCAS Martyn;  MARCELLO Lucio;  MARTIN Patrick;  MCGINNITY Phil;  O'HANLEY Jesse;  OLIVO DEL AMO Rosa;  PARASIEWIECZ Piotr;  PUSCH Martin;  RINCON Gonzalo;  RODRIGUEZ Cesar;  ROYTE Josh;  TILL SCHNEIDER Klaus;  TUMMERS Jeroen;  VALLESI Sergio;  VOWLES Andrew;  VERSPOOR Eric;  WANNINGEN Herman;  WANTZEN Karl;  WILDMAN Laura;  ZALEWSKI Maciej; 

2021-01-19

NATURE PUBLISHING GROUP

JRC121139

0028-0836 (online),   

https://www.nature.com/articles/s41586-020-3005-2,    https://publications.jrc.ec.europa.eu/repository/handle/JRC121139,   

10.1038/s41586-020-3005-2 (online),