Figure 1

Boosted Regression Tree (BRT) summary showing the relative influence of geographical variables (in orange), water physico-chemical variables (in blue) and land use (in green) on freshwater fish functional diversity (calculated through the functional dispersion, FDis metric, applied to the ecological traits of species) for native (left panel) and exotic (right panel) species. The variable abbreviations stand for: Long – longitude, Lat – latitude, Alt – altitude, NH₄⁺ – ammonia, BOD – biological oxygen demand, TSS – total suspended solids, T – water temperature, NO₃ – nitrate nitrogen, COD – chemical oxygen demand, EC – electrical conductivity, TP – total phosphorus, Agric – agricultural, Other nat – other natural area, Freshw – freshwater, Forest – forest, Urban – urban and Brackishw – brackish water.