Functional diversity patterns reveal different elevations shaping Himalayan amphibian assemblages, highlighting the importance of morphologically extreme individuals

•Amphibian functional diversity differed between elevational zonations.•Amphibian functional distinctiveness existed across elevational zonations.•Functional diversity was largely contributed by a few functionally extreme amphibians.•Functional vulnerability of amphibian assemblages existed throughout all the zonations.•High elevational area should be in particular well protected to maintain amphibian functional diversity.