A simple method to assess the fragmentation of freshwater fish meta-populations: Implications for river management and conservation

• A river connectivity index was modified to assess fish population fragmentation. dam may deeply impact a species but not the network and vice versa. Dam varies with dispersal capability distance between populations. The can be used prioritise mitigation for single or habitats. Rivers are very vulnerable fragmentation caused by presence of man-made barriers. To restore basin connectivity, numerous indices have been developed calculate optimise barrier actions. These methods usually whole basins, sometimes it is useful analyse certain elements interest. main goal this study develop simple method specific riverine habitats meta -populations. framework Dendritic Connectivity Index (DCI) created Cote et al. in 2009 changed Population (PCI). This would depend on number populations, total length occupied each population, barriers river. outcome percentage that measures degree -population. PCI tested four Iberian different capabilities: Salmo trutta , Luciobarbus comizo Anaecypris hispanica Cobitis vettonica . results show natural populations (without considering dams) 7.95–47.48%. most connected -population L. while naturally fragmented A. When large impassable dams were added 2.19–16.48%. Dams reduce 5.37 30.99 points. ranked according their studied allows find out isolated -populations It also prioritization decisions such as removals new location selection. aid creation ecological corridors endangered important