Vascular epiphytes on large old-growth trees: the influence of ecological zones in epiphyte species composition

Abstract

Abstract The over time establishment of epiphyte communities on large old-growth trees has shown that epiphyte numbers tend to rise in relation to the size of their phorophytes. The objective of our study was to perform a floristic survey of vascular epiphytes on last large old-growth trees in a subtropical forest and to compare species richness between conifers and hardwood trees. Nine phorophytes (0.9 - 2.1 m in diameter and 22 - 40 m in height) in one of the last remaining old-growth forests were selected for study. Epiphyte locations on the trees were divided into the following ecological zones: base of the trunk: first 1.30 m above ground; mid-section of the trunk: from the trunk base to the crown base; crown base: 1.30 m below the crown; and crown. We found 30 species of epiphytes, distributed in 21 genera and 11 families. Among the distribution patterns of the epiphytes there were species predominantly occurring in the basal or mid-trunk region of the phorophytes (e.g., Billbergia nutans); other species occupied the upper portion of the phorophyte, between the mid-trunk and the crown (e.g., Vriesea reitzii). The relationship between size in large old host trees and vascular epiphyte species richness is not positive and linear. Vascular epiphyte species richness by host trees species was indifferent among large old trees species, even though Ocotea porosa (hardwood) has an apparently larger crown greater and show more abundance of epiphytes than that of Araucaria angustifolia (conifer).