Ramp Neale, Jennifer M. , Neale, Richard B. , Ranker, Tom A. .
Identifying the dominant source regions for the colonization of Hawaiian fern species using a trajectory and dispersal model.
Levels of floral endemism in the Hawaiian Islands are some of the highest of any geographic region in the world (90% for flowering plants, 77% for ferns and lycophytes). The current high islands of the archipelago are located approximately 4,000 km from the nearest continent. All species migrating to the Hawaiian Islands have arrived via long-distance dispersal either through the air or in the water. Source regions for original colonizing ancestors of Hawaiian fern and lycophyte species have been hypothesized as Indo-Pacific (48%), Pan-Tropical (20.8%), American (11.9%), obscure (11.1%), Boreal (4.4%), and Austral (3.7%) (Fosberg 1948). Recent studies have speculated as to the transport pathways via which fern spores were transported to the Hawaiian Islands and colonization events were achieved. Potential proposed pathways include the sub-tropical jet stream, shifts in the Hadley Circulation-Inter tropical convergence zone, easterly trade winds, and individual storms from Mesoamerica. The first three possibilities represent a simplified view of atmospheric flow, but are unlikely to represent the actual trajectories of individual spores. The transport of fern spores in the atmosphere can be viewed as analogous to the transport of inert tracers (e.g., dust particles) studied using meteorological models, since the particle sizes are approximately the same. We will show initial efforts to utilize an existing trajectory and dispersal model – used extensively in pollution studies – to test the probability of spores originating from the potential source regions reaching the Hawaiian Islands.
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1 - Denver Botanic Gardens, Research, Herbaria & Records, 909 York Street, Denver, CO, 80206, United States
2 - National Center for Atmospheric Research, PO Box 3000, Boulder, CO, 80307, United States
3 - University of Colorado, University Museum & Department of Ecology and Evolutionary Biology, 265 UCB, Boulder, Colorado, 80309, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Lake Michigan/Hilton
Date: Monday, July 9th, 2007
Time: 9:15 AM