Exploring the biodiversity in temperate rainforest canopies of Chiloé island, southern Chile

Temperate rainforests of southern South America are characterized by an evergreen canopy, with scattered old, emergent trees, densely covered by epiphytes. The biodiversity associated with this forest canopy remains largely unknown. Here, we document the composition of ferns, angiosperms and non-vascular plants, invertebrates and vertebrates associated with two emergent tree species (>25 m high) in coastal forests of Chiloé Island (41º 50'S), Chile: the endemics Eucryphia cordifolia (Eucryphiaceae) and Aextoxicon punctatum (Aextoxicaceae). Our objectives also included understanding the direct and indirect effects of epiphytes on arthropod and bird abundance. We conducted field surveys comparing invertebrate and vertebrate abundance between trees with intact epiphyte assemblages (control) and trees whose epiphytes were removed. We accessed the forest canopy using tree-climbing techniques. Each tree supported, on average, 150 kg (dry weight) of epiphytic material (60-80% humidity). Roots and dead organic matter composed 70% of the epiphytic material, while green biomass was dominated by Hymenophyllum ferns (13 spp.), the hemiepiphyte Pseudopanax laetevirens (Araliaceae), and Fascicularia bicolor (Bromeliaceae). Other four species of vascular epiphytes and vines made up the remaining biomass. Epiphytic material supports a large diversity of invertebrates, including annelids, mollusks, and an undetermined number of insects and arachnids. Our initial results show that large trees with epiphytes attract more birds than trees without epiphytes. Old emergent trees can be important reservoirs of plant and invertebrate diversity which influence bird abundance in the forest. Future steps of this work include assessing the trophic structure of the canopy assemblage of invertebrates and birds. Acknowledgements: Fondecyt-1050225.