The use of benthic indicators in Europe, from the Water Framework Directive to the Marine Strategy Framework Directive.

The European Water Framework Directive (WFD; 2000/60/EG) and the European Marine Strategy Framework Directive (MSFD; 2008/56/EC) were umbrella legislations for fresh and marine waters. It is a challenge for the scientific community to translate the principles of these directives into realistic and accurate approaches. Both directives have common principles, which were tackled differently. For the WFD, this was executed during the last decade, and many results of it were already published. This process delivered valuable knowledge on which the implementation of the MSFD can be founded. Therefore, the ICES Benthos Ecology Working Group aimed at compiling the lessons-learnt from the application of benthic indicators in the WFD to be implemented within the MSFD through the description of (1) how the principles are theoretically filled in by both directives, (2) how the process is tackled in the WFD process and (3) what these insights might mean for the implementation of the MSFD. A first main principle is the realization of the ecosystem approach. Secondly, the comparability of benthic indicators, class boundary settings and the relationships between indicators and anthropogenic pressures are highlighted. Thirdly, some aspects related to the monitoring requirements of both directives, are discussed. We conclude that testing and integration of the different approaches was facilitated during the WFD process and lead to further insights and improvements. This facilitate the selection of the most accurate approach for each purpose (principle, region, water type, etc...). Expert involvement in the entire process proved to be of vital importance.