UCB Moorea Class: Biology and Geomorphology of Tropical Islands

Ferns present an interesting case in island biogeography because of their unusually high dispersal ability. A general survey of the filmy ferns (Hymenophyllaceae) of Moorea, French Polynesia was undertaken by observing distribution in the field, conducting tests of desiccation tolerance, and inferring a phylogeny based on morphological characters. A total of 12 filmy fern species (including three species previously unreported in the literature for Moorea) were found to occur in moist, wellcovered habitats throughout the island, with distinct sets of high elevation and low elevation species. Five species were included in an experiment to determine relative degree of desiccation tolerance; results indicate that terrestrial species have lower desiccation tolerance than epiphytic or epipetric species. In order to place the Moorea filmy ferns in the larger archipelago context, eight additional Society Island species were included in the phylogeny for a total of 20 taxa based on 21 morphological characters; interspecies relationships reflect the taxonomy of Hymenophyllaceae sensu lato. Filmy fern species are widely dispersed throughout the Society Islands, and there is no indication of an adaptive radiation on Moorea.