Host tree species effects on long-term persistence of epiphytic orchid populations

The destinies of epiphytic orchids (about 70% all orchids) are linked to their host trees. However, there is little information on if differences in trees characteristics can affect the long-term persistence orchid populations, and how this might vary under different climatic conditions. We compared population dynamics two species, Alamania punicea Oncidium brachyandrum growing with contrasting leaf phenologies: deciduous Quercus martinezii semideciduous Q. rugosa , over 3 years varying levels rainfall, a montane tropical oak forest Oaxaca, Mexico. Using data from > 500 individuals 63 trees, we applied linear mixed effects models, Integral Projection Models, Life Table Response Experiments identify tree vital rates growth rates. For both survival did not differ between species during wettest year. driest year were higher semi-deciduous than . Host fecundity for A. but O. was host. λ values similar hosts intermediate years, significantly lower (Δ = 0.28) This due primarily slightly 0.03) year, reproduction. 0.13 0.15, respectively). growth. populations appear more vulnerable dry conditions likely its smaller pseudobulbs, hence water-storing capacity. Our results show that influence these across time. highlight importance maintaining diversity ensure persistence.