The outer canopy of the lowland rain forest can be classified as an azonal dry habitat, or azonal xeric layer, due to its harsh climatic conditions that differ from understory climate. In both forest systems epiphyte species have markedly vertical zonations. For the first time absolute total amounts of PAR obtained by epiphyte stands could be measured for different natural forest habitats. The extremes and the daily variations of radiation are less in montane rain forest compared with lowland rain forest. This can explain, why there exists a considerable niche overlap in vertical zonation of some generalistic epiphyte species with a great ecological plasticity in the montane rain forest.
Disturbances seem to have a great influence on the floristic composition and abundance of epiphytes.
Some families are highly sensitive to large scale disturbances, reacting with a considerable decrease of species. Dynamic processes in natural habitats at the Surumoni study site are most recognizable in the presence of ant garden epiphytes. The occurrence of the four epiphyte species, specialized in growing in ant nests, were mainly restricted to the two year old gap areas of the investigation plot.