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In the wake of Hurricane Iniki.

The devastating fury of Hurricane Iniki, which swept Hawaii's island of Kauai last September, may both benefit and harm ecosystems already disrupted by invasions of alien organisms.

While Iniki's driving rain and sustained winds of 130 miles per hour flattened houses and toppled telephone poles, they also destroyed vast stretches of dry forest on Kauai, says environmental entomologist Adam Asquith of the University of Hawaii's Kauai Research Station in Kapaa. Asquith says the hurricane wiped out stands of Acacia koa - a hardwood tree prized for its strong, amber-colored timber - on Kauai's southwest quadrant.

"It looks as if the canyons [between the island's long-dormant volcanoes] acted as wind funnels," Asquith told SCIENCE NEWS. "Lots of trees and other vegetation are down."

Asquith says this destruction might accelerate the growth of two alien plant species that have recently gained footholds on Kauai: wild blackberry and a creeping vine called banana poka, which is notorious for strangling A. koa. Such alien plants thrive in areas where native vegetation has been disrupted. Blackberry and banana poka already pervade parts of Kauai damaged by Hurricane Iwa in 1982, Asquith says.

However, Hurricane Iniki seems to have spared the rain forests, which are home to Kauai's spectacular bird species - many of which are endangered or threatened with extinction - according to Asquith. "I don't think any [bird species] are restricted to dry forest, the areas that were most heavily hit," he says.

In fact, Asquith says, Hurricane Iniki might even benefit the Kauai bird population over the short term by providing new food sources for insects that eat fallen trees and leaf litter. "Once these insect populations start increasing, there might be an increase in food supply for the birds," he projects.

Over the long term, however, Asquith fears Hurricane Iniki will have a harmful effect on Kauai's ecology. In particular, he is concerned about the destruction of existing patches of a creeping, goldenrod-like shrub called po'ola nui that grows only on Kauai. This shrub, which is already in danger of extinction, hosts native files from the genus Tephritidae. The extremely rare files lay their eggs on the po'ola nui plant, forming galls that may keep the plant growing laterally, an adaptive advantage that allows the shrub to spread. If the shrub disappears, Asquith says, the files will not be far behind.
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Title Annotation:Cover Story; hurricane destruction may allow alien organisms to thrive and endanger Kauai's ecosystem
Author:Ezzell, Carol
Publication:Science News
Article Type:Brief Article
Date:Nov 7, 1992
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