Diversity of Species and Interactions in the Upper Tree Canopy of Forest Ecosystems

SYNOPSIS. The importance of the organisms and processes thatoccur in forest canopies is becoming increasingly recognizedin relation to understanding biodiversity. The upper tree canopyof many forest ecosystems fosters extremely diverse communities,particularly of vascular epiphytes and arthropods. Epiphytesalso contribute to the diversity of birds because they add tothe total amounts of resources, provide opportunities for resourcespecialization, and temporally spread available resources inthe canopy throughout the year. Epiphytes also contribute toecosystem processes such as nutrient cycling because they gainaccess to nutrient sources originating outside the ecosystemand transfer them to other members of the forest, thus functioningas a "keystone" resource.