Landscape determinants of genetic structure for Schizopygopsis younghusbandi in the Yarlung Tsangpo River drainage, Tibetan Plateau

•Haplotype diversity was more sensitive than nucleotide diversity to population dynamic fluctuations for Schizopygopsis younghusbandi.•There was widespread high level of genetic differentiation among geographical populations.•The spatial pattern of genetic diversity was consistent with the central-marginal hypothesis.•The formation process of genetic differentiation accorded with the Isolation-by-Environment model.