Aiming to understand the factors that limit species radiations and coexistence, I investigate the ecology of epiphytic microhabitats. The Tropical Andes and Mesoarmerica are two leading hotspots in terms of their numbers of plant endemics and therefore an ideal place to study species radiation and biodiversity patterns. A vast epiphyte richness is one of the characteristics of the topical humid montane forest, especially in the Neotropics. For my project, I study the microhabitat segregation of grammitid ferns (Polypodiaceae) in montane forest of Costa Rica and Ecuador. The majority of this epiphytic fern group can be found in the tropics where they are most diverse in montane rainforests between 2000 and 4000m of elevation. The specific aim of my study is to compare the microhabitats within trees and among different areas, to understand how ecologically different the niches are and how that allows species to coexist.