Mosquito control vital to isles' native birds


POSTED: Monday, June 01, 2009

Global warming threatens to push endangered native Hawaiian honeycreepers closer to extinction unless the likely resulting increase in mosquitos that carry avian malaria and the pox virus is curtailed, federal scientists warn.

Honeycreepers have been able to survive by living at elevations higher than 4,000 feet where the temperature is cold enough to reduce mosquito populations.

But with a projected 3.6-degree increase sometime after 2050, about 60 to 96 percent of high-elevation refuges will disappear, said Carter Atkinson, a research microbiologist with the U.S. Geological Survey.

Atkinson said global warming would affect nearly 60 percent of the Hanawi Natural Area Reserve in East Maui and as much as 96 percent of the Hakalau Forest National Wildlife Refuge on Hawaii island.

Atkinson said for other islands with lower elevations, such as Kauai, where disease transmission is seasonal, the diseases would be occurring throughout the year, and the temperature changes would be catastrophic for honeycreepers.

“;Such changes would likely push remaining populations of threatened and endangered honeycreepers to extinction and cause severe declines in other honeycreepers not now endangered but susceptible to avian malaria,”; he said.

Honeycreepers in Hawaii have already dramatically declined in population.

Of some 41 species and subspecies of honeycreepers, 14 are on the federal endangered list, and 17 are believed to be extinct, according to the Journal of Avian Medicine and Surgery.

Atkinson said managing the midelevation areas by reducing habitats for mosquitos will become increasingly important, including the reduction of feral pigs, cattle and goats.

Mosquitos are able to breed in animal feces and in water-collection areas made through hoof prints and eating into the trunks of native ferns.

He said watershed partnerships in recent years have helped to keep out invasive species and bring back the native forests.

“;They're doing quite a bit of fencing,”; he said. “;The survival of these species into the next century may ultimately depend on our ability to remove or offset introduced threats and restore native forests from sea level to tree line.”;