1) Understanding the mechanisms underlying species assembly is a central focus of plant ecology and is crucial to revealing how plant communities are structured. However, the temporal limitations of most terrestrial plant communities preclude collection of species assembly data in a tractable time-frame. 2) The aim of this study is to investigate the importance of dispersal potential, as estimated by inter-specific variation in sexual and asexual expression, as a predictor of patch chronosequence assembly for epiphyllous (leaf-inhabiting) bryophytes. Secondarily, we investigate whether spatio-temporal patterns in patch turnover and compositional variation infer evidence of local (within-patch) population processes. The frequency and distribution of 55 epiphyllous bryophytes across five leaf age classes were studied on an understory shrub Piper grande (Piperaceae) in pre-montane Panamanian tropical forest. Logistical models were used to test whether inter-specific variation in dispersal-related life history traits predicts assembly order. Beta diversity and ordination analyses were employed to examine nestedness versus turnover, and probe for repeatable patterns in patch chronosequence assembly, respectively. 3) Our results emphasize the importance of dispersal potential on species assembly patterns as earlier arrivals exhibit greater probabilities of sexual and specialized asexual expression. High turnover coupled with temporal convergence in species composition also point to evidence of within-patch biotic filtering. 4) Synthesis: Epiphylls are locally diverse in humid tropical forests worldwide; however, the mechanisms which maintain their high local diversity are unknown. This study suggests that inter-specific variation in dispersal capacity in combination with diffuse indirect effects are the principal contributors to the high alpha-diversity of these ephemeral metacommunities.