From 2011 to 2014 I worked at the Centre for Hydrographic Studies in Madrid, dealing with the classifications of streams and rivers in Spain for the implementation of the WFD, and its relationship with the Habitats Directive. During this period, I also investigated in other areas such as: invasive species ecology, the effects of dams on river communities -fish and macroinvertebrates-, the National Catalogue of Threatened Habitats -lotic systems-, the ecology of the estuary of the Guadiana or the emissions of nitrous oxide from aquatic ecosystems in Spain.