Value of human‐modified forests for the conservation of canopy epiphytes

Abstract

AbstractHuman‐modified forests—HMFs—now cover more area worldwide than primary forests and could help buffering the ongoing species loss. However, their role in protecting canopy epiphytes remains unclear, partially because these communities require large trees, high humidity, and shade, conditions which are rare in HMFs. Here, we assessed how canopy epiphytes, in different ontogenetic stages, are structured in HMFs. Specifically, we evaluated how species richness, total abundance, and community composition, and how abundance of seedlings and juveniles, are affected by the local and landscape context in the Atlantic Forest of Brazil. Across all sites, we found 82.9% of species and 75.5% of individuals exclusively in old‐growth forest, while HMFs hosted only 15.5% of all species, sharing 75% of their species with old‐growth forests communities, and pastures hosted 1% of species richness and 2.8% of individuals sharing 60% of their species with old‐growth forest communities. We also found that seedling and juveniles were twice as abundant than adults in old‐growth forest, similarly abundant to adults in HMFs and absent from pastures. Low numbers of individuals in early ontogenetic stages in HMFs and pastures are likely to impact future generations of epiphytes in these areas. Although HMFs provide important refuge for many species, our results show that they do not provide suitable conditions for the maintenance of current or future canopy epiphyte communities. Our findings suggest that conserving large continuous old‐growth forests is the only viable conservation option for protecting most vascular epiphytes.Abstract in Portuguese is available with online material.