Conclusion
Overall, these data have both regional and general significance. Regionally, they provide explanations for changing community composition and trait expression in Himalayan rivers. More generally, they expand the understanding of how trait distributions and assemblages are the result of a complex interplay between trait filtering along environmental gradients coupled with evolutionary processes. There exists a clear phylogenetic imprint that contributes to contemporary species-trait–habitat relations in river bird assemblages in the Himalayan Mountains. In the light of large—scale human alterations to the biosphere, represented particularly strongly in rivers, models of trait-environment relationships like ours can be instrumental in predicting future range shifts in the distribution of species and traits. Our study reiterates that the simultaneous assessment of phylogenetic relatedness among co-existing species with trait-habitat analyses can benefit the understanding of species assembly patterns across regional fauna.