Plume, Olofron , Wright, Margaret E. , Ranker, Tom A. , Geiger, Jennifer M. O. .
Alternate pathways of fern dispersal to the Hawaiian Islands, Part 2: Grammitids.
THE Hawaiian Islands are the most isolated large group of islands on Earth, yet they are home to nearly 200 species of native ferns and lycophytes. Although species endemism is high (80%), there seems to have been little autochthonous speciation, as Hawaiian fern lineages are generally species-poor. Thus, the probable number of successful colonizations of fern species to the islands compared to the number of extant species is relatively high compared to flowering plants, which generally are represented by more species-rich lineages. Because fern spores are most likely dispersed through the air via the wind, weather and climate patterns are undoubtedly important factors determining the geographical origins of the ancestors of Hawaiian ferns. We are conducting molecular biogeographical studies of multiple groups of Hawaiian ferns to ascertain the likely geographical origin of each group and to explore the nature of shared pathways of dispersal across unrelated taxa. Grammitid ferns (Polypodiaceae: Grammitidoideae) are represented in the Hawaiian Islands by three genera: Adenophorus, Grammitis, and Lellingeria. Our ever-expanding molecular phylogenetic study of grammitids worldwide, has provided strong evidence that the ancestors of each genus represented in the Hawaiian Islands dispersed to the islands independently and via different pathways of dispersal. We will present evidence showing that: 1) the ancestor of Adenophorus mostly dispersed from the Neotropics, possibly via the trade winds or a storm; 2) the ancestor of the Grammitis hookeri group dispersed from the Indo-Pacific, possibly via the jetstream; and 3) the ancestor of Lellingeria is possibly of south Pacific origin, having dispersed across the equator from the Marquesas Islands, via a climate-based, trans-equatorial mechanism previously proposed for Metrosideros polymorpha (Myrtaceae). So, how did ferns get to Hawai’i? The answer, my friend, is blowin’ in the wind.[c.e.:srb]
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1 - University of Colorado, University Museum & Department of Ecology and Evolutionary Biology, 265 UCB, Boulder, Colorado, 80309, USA
2 - Caroll College, Department of Natural Science, 1601 North Benton Ave., Helena, Montana, 59625, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 31st, 2006
Time: 2:00 PM