Fig. 2 Population genetic diversity (genome-wide heterozygosity (π, a–d) and inbreeding coefficient (F , e–h)) of the four target species. The x-axes show the value of each index that is associated with the primary basins (GAN: Gandaki Basin; KOS: Koshi Basin; MEK: Mekong Basin; YAN: Yangtze Basin; IRR: Irrawaddy Basin; SAL: Salween Basin) and subbasins (Lehner and Grill 2013, http://www.hydrosheds.org/page/hydroatlas). The colours of the box plots are consistent with the colours shown in the map of Fig. 3.