Precipitation drives the fall of epiphyte bromeliads in an Andean tropical forest

Abstract Mortality of epiphytic bromeliads could increase due to dense independent factors, reducing their diversity and contribution to ecosystem functioning. For seven months, we assessed the effect of precipitation and a mechanical factor on the fall of bromeliads, including their richness, abundance, population size, and traits. Our study was conducted in a protected area of Colombia’s Andean tropical forest, where we collected individual-fallen and branch-fallen bromeliads. We then established their taxonomical identity, developmental stage, phytosanitary status, and morphological traits. We examined the relationship between the canopy bromeliad community and fallen bromeliads, and the effect of precipitation and a mechanical factor (the diameter of branches with bromeliads) on fallen bromeliads. The richness and abundance of fallen bromeliads increased with the precipitation, branch diameter, and abundance of canopy bromeliads. Precipitation is the main factor influencing bromeliad fall, affecting juvenile bromeliads more proportionally. Precipitation increases the likelihood of detachment of the bromeliad through an increase in the bromeliad weight, less resistance to heavy raindrops by the root system, and water accumulation in the tree’s bark, and desorption by roots. Although a bromeliad is typically considered dead when it falls, our findings indicate that fallen bromeliads are predominantly juvenile individuals in good phytosanitary condition. This suggests that bromeliad conservation strategies should prioritize the recovery of fallen bromeliads, especially in areas with high risks of local extinction.