Abstract Understanding demographic processes is critical for conserving threatened epiphytes, yet detailed population studies remain rare. We analysed population dynamics in the context of phorophyte structure of the threatened orchid Cattleya quadricolor , endemic to Colombian tropical dry forest, to identify conservation priorities across eight fragmented subpopulations. Using stage-structured population projection models, we estimated both asymptotic growth rates ( λ ) and transient dynamics to assess long-term persistence and short-term vulnerability. Across all sites, λ values were consistently < 1, demonstrating that populations are in decline. Demographic structure was strongly skewed towards adult individuals, with seedling and juvenile stages strikingly underrepresented, suggesting recruitment failure as a major population bottleneck. Transient analyses further revealed limited capacity for short-term recovery after disturbance, especially in small populations. Phorophyte composition further influenced risk, as small host trees provide less stable substrates and greater accessibility to collectors, exacerbating vulnerability. Conservation priorities therefore differ amongst populations. In some sites, immediate protection of adult plants, targeted management of phorophyte assemblages and stronger enforcement against illegal collection are most urgent. In others, actions to enhance seedling recruitment, establish ex situ collections and reinforce reintroduction programmes are critical to buffer populations against extinction risk. By integrating asymptotic and transient demographic models with habitat context, our study demonstrates a comprehensive framework for evidence-based conservation of rare epiphytes, and underscores the importance of demographic approaches and phorophyte context for guiding orchid conservation in fragmented tropical dry forests.
Torres et al. (Fri,) studied this question.