UCB Moorea Class: Biology and Geomorphology of Tropical Islands

Tropical forest epiphytes have been shown to be important to net primary production and, in some cases, nitrogen fixation. They have also been shown to be good bioindicators of pollution and are thus important study organisms. This study focused on epiphytes (primarily lichens and mosses) growing on Pemphis acidula (J.R. and G. Forster) in Moorea, French Polynesia and the role their environment played in community dynamics. Field sampling and laboratory experiments were carried out on three different motus off of Moorea, focusing on Motu Tiahura where the northeast and northwest sides were sampled, estimating percent cover of epiphytes. Environmental data (aerial cover, lagoon cover, temperature, humidity, wind speed) was recorded from the study sites and relationships between environment and distribution were determined. A total of 9 taxa were found on the motus. Laboratory experiments tested the effect of certain environmental variables on some taxa. The northeast site was much more species rich than the northwest site, though the two environments were not significantly different. Lab results showed significant relationships between light and heat and the moss Calymperes, lichen Physcia cf clementei (Lynge) and a possible, undetermined lichen. Light, heat and wind most likely limit the abundances of Calymperes and P. clementei as they contribute to desiccation of the epiphytes.