Transient dynamics is a growing concern in population biology and is particularly relevant for rare species that colonize ecotones. Euptelea pleiospermum is a threatene d species endemic to eastern Asia and a common component in riparian forests. Transient amplification and attenuation envelopes, as well as elasticities of population growth rates and population momentum, were explored based on stage-structured transition matrix models to articulate the population dynamics of this species. The results demonstrated that transient population growth rates and eventual population sizes (i.e. population momentum) differed sufficiently from asymptotic expecta tions. But transient population fluctuations as measured by amplification and attenuation envelopes were modest in size. The potential of transient amplification and attenuation are perhap s associated with reproduction of early mature individuals and the mortalit y of juveniles, respectively. Both asympt otic and transient population growth of E. pleiosper mum are most sensitive to survival, less sensitive to tree growth, and largely insensitiv e to fecundity, whereas the importance of vegetative reproduction is pronounc ed over fecundity. Underrepresented or overrepresented stages in the initial structure relative to stable stage distribution have comparatively larger elasticities of transient population growth and population momentum, suggestin g the importance of vital rates of ‘‘biased’’ stages in driving transient dynamics. Our results highlight the use of transient envelopes and elasticities in guiding the adaptive management for the target species.