Mechanisms Regulating Epiphytic Plant Diversity

Epiphytic plants are important components of the forest ecosystem, but little is known about their ecology due to logistical constraints and the lack of a conceptual framework to guide epiphyte community studies. Given the present state of knowledge and renewed interests in epiphyte community studies, a mechanistic framework is needed to guide investigations of epiphyte assemblages. This article identifies six putative mechanisms of epiphyte species diversity, and highlights possible direct and indirect linkages among the mechanisms. The mechanisms include constrained dispersal, slow growth rate, substrate availability, host tree mortality, disturbance, and global climate change. They are identified as inherent, local- and stand-level, and landscape-level mechanisms. Evidence supporting the proposed mechanisms and their linkages is typically inductive due to inadequate observational and manipulative studies. Sufficient testing and experimental manipulations over broad spatial and temporal scales are necessary for future predictions of epiphytic plant diversity patterns.