Yoshinaga, Alvin .
Desiccation Tolerance of Island Seeds and the Establishment of Island Floras.
The seed desiccation tolerance characteristics of ten tropical and subtropical island floras in the Indian and Pacific Oceans were predicted by taking worldwide desiccation tolerance data for each plant family from the Royal Botanic Gardens-Kew Millennium Seed Bank Seed Information Database and applying it to the flora of each island group. In laboratory studies of seeds from the Hawaiian Islands, the predicted distribution of seed desiccation tolerance closely matched the observed distribution. For both indigenous and endemic species, floras of the seven oceanic islands had significantly lower percentages of predicted desiccation intolerant seeds overall than the three continental islands (p = 0.03). Incidences of predicted desiccation intolerance among seeds of oceanic island floras (4.1-10.9% with one 18.9% outlier) were comparable to the worldwide average for all seeds (6.1%). Those of continental islands were higher (15.2-19.8%). Conventional wisdom predicts that floras of moist, warm regions should have high proportions of desiccation intolerant seeds. However, water barriers are a stronger filter against dispersal of desiccation intolerant seeds than against tolerant seeds, and establishment after arrival is more difficult for intolerant seeds. Dispersal and establishment constraints favor plant families with desiccation tolerant seeds as colonists of oceanic islands. Besides its biogeographic significance, this observation has practical implications for conservation of island plants, since desiccation tolerant seeds can readily be banked using conventional seed banking techniques.
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1 - University of Hawaii, Center for Conservation Research and Training, Honolulu, Hawaii, 96822, USA
Presentation Type: Oral Paper:Papers for Topics
Date: Monday, July 28th, 2008
Time: 5:00 PM