This WP will focus on how fragmentation of river-scapes interacts with other components of global change. The effects of physical barriers in rivers depend strongly on streamflow and thus interact with water abstraction, climate change, and other anthropogenic perturbations. We will use the Iberian Peninsula as a study area for this purpose, because its streams and rivers experience extensive anthropogenic perturbations, including invasions of non-native fish species, eutrophication, water abstraction, climate-driven hydrologic changes, and building of dams and weirs (Benejam et al. 2010; Murphy et al. 2015). We will build on an extensive data set recently compiled for the Ebro river basin, where many endemic fish species are declining and invasive species are thriving (Fig. 2). The precise effects of different anthropogenic perturbations and particularly connectivity on these biodiversity changes is unknown (WP leader Emili García-Berthou).