Tropical Rainforest Ecology from a Canopy Perspective

Many processes that are fundamental to tropical rainforest maintenance and regeneration take place in the forest canopy. Recently developed access techniques afford biologists nondestructive means to document and quantify canopy biota and their accompanying activities and interactions. Results from studies involving within-canopy observations and measurements of nutrient cycling, epiphyte distribution, species diversity, nutrient cycling, and animal activities in primary and secondary forest are reviewed to identify specific areas of investigation and scientific questions that can be addressed from a canopy perspective. The ongoing progress of current canopy ecology projects in tropical rainforests is described. New data on interactions between neotropical canopy birds and plants and the effects of forest conversion to pasture on these organisms in a neotropical cloud forest suggest that trees left standing in pastures can serve as "island refuges" for a wide variety of bird species using canopy resources such as epiphyte flowers and fruits and accumulated dead organic matter on branches and trunks. This study points out the need for more basic ecological research on canopy ecology in both primary and converted forests.