DOES THE SIZE OF THE TREES DETERMINE THE RICHNESS AND DISTRIBUTION OF VASCULAR EPIPHYTES IN AMAZONIAN FLOODPLAIN FORESTS?

Vascular epiphytes (VE) are among the most threatened group of plants due to the extraction of trees (phorophytes). Yet, surveys and ecological information on vascular epiphytes are rather scarce particularly in wetlands. To understand the effect of tree assemblage on the occurrence of VE and in order to elucidate ecological patterns of distribution and composition, 16 (25 x 25 m) permanent plots were sampled in an oligotrophic floodplain forest (igapó - PELD MAUA) and compared to the same amount and size of plots in a nutrient-rich floodplain (várzea - RDS Mamirauá), both in Central Amazon. All trees and associated VE were counted and identified. The diversity in várzea is driven by the turnover of epiphytes in trees with different diameters, while in igapó there is a pronounced concentration of VE in trees with smaller diameters. Conservation actions in várzea forests should prioritize the maintenance of forest structure, sustaining taxonomic diversity in all diameter classes of trees. In igapó forests efforts to conserve epiphytes must first consider the taxonomic identity and, after, size of trees in the community. The comparison of our results with those of other PELDs in wetlands and other ecosystems will enhance our knowledge on the biogeographic patters and constrains on the distribution of this important botanical component