Figure 2
Species richness (a), functional richness (b) and functional redundancy (c) of fish communities across lakes, rivers and estuaries in France, Spain and Portugal. Boxplots represent the general trends for each aquatic system (all), as well as trends for the system categories, i.e. small and large lakes, small and large estuaries, headwater streams (HWS), medium gradient rivers (MGR), lowland rivers (LLR), and Mediterranean streams (MES). For each aquatic system, letters indicate categories that were not significantly different after a post-hoc Kruskal–Wallis test (P-value ≥ 0.05). The maps display the geographical distribution of indices values. Functional diversity was calculated from a combination of five traits, i.e. fish size, vertical position, trophic group, spawning habitat, and swimming mode. The functional redundancy of each assemblage was assessed from the average area under the curve of 999 random trajectories of species extinctions. The maps were built using the libraries ‘sp’ and ‘rgeos’ available in R software (www.r-project.org) and the shapefile of the European coastline was provided by the European Environment Agency and is freely available at https://www.eea.europa.eu/data-and-maps.
