Local and regional determinants of vascular epiphyte mortality in the Andean mountains of Colombia

1. We present the first large-scale assessment of vascular epiphyte mortality in the neotropics. Our goals were to explore the primary types of vascular epiphyte death and to identify local and regional determinants of epiphyte mortality in natural forests located 60 to 2900 m a.s.l. in the Colombian Andes. 2. Based on two consecutive annual surveys, we followed the fate of 4247 epiphytes to estimate the epiphyte mortality rate on 116 host trees at nine sites. A logistic regression analysis for proportional data with a binomial distribution of the error was applied to determine the probability of epiphyte death in relation to local and regional explanatory variables. 3. The overall epiphyte mortality rate was 7.5 ± 1.1% yr−1 (mean ± standard error). Non-mechanical factors, such as desiccation, accounted for a mortality rate of 1.9 ± 0.3% yr−1. Mechanical factors, such as falling branches, accounted for a mortality rate of 5.6 ± 1.1% yr−1. According to generalized linear modelling analys...