Study: Climate change and avian malaria are shrinking the ranges of Hawaii’s native birds

Akekee-Hawaii-USGS-660
‘Akeke‘e, an endangered Hawaiian honeycreeper, is projected to lose all of its range by the year 2100. Photo by Carter Atkinson/U.S. Geological Survey

Think of it as a one-two punch for Hawaii’s honeycreepers and other songbirds.

Avian malaria has already forced most of the state’s forest birds to move to refuges above 4,900 feet, where temperatures are typically too cool for the mosquitos that carry the disease.

Now climate change promises to cause the birds’ ranges to shrink even further. According to scientists from the U.S. Geological Survey and the U.S. Fish and Wildlife Service in Honolulu, the birds may lose between 60 and 100 percent of their remaining habitat by the end of the century.

The researchers used a species-sightings database, regional climate projections, and distribution models to learn how potential climate shifts would affect the ranges of 20 Hawaiian bird species at high elevations.

They determined that, by 2100, three species — ‘Akeke‘e, ‘Akikiki, and Puaiohi — are likely to lose all of their ranges; that three others — Hawaii ‘Akepa, ‘Akohekohe, and Maui Parrotbill — may lose more than 90 percent of their ranges; and that four others could lose 60 to 78 percent of their ranges.

“As dire as these findings are, they do not mean that these bird species are doomed,” says lead author Lucas Fortini. “Instead, our findings indicate what may happen if nothing is done to address the primary drivers of decline: disease spreading uphill into the few remaining refuges.”

Fortini and his co-authors identify several conservation actions that could help the birds: aggressive reforestation of former habitats at higher elevations, maintaining captive populations of species that are extremely endangered, and translocating species with small ranges to higher elevations outside of their known historic ranges.

And they argue for the development of techniques that would interrupt the cycle of malaria transmission and mortality. “Such actions could include vector control and genetic modification of both birds and mosquitos,” they write in the online journal PLoS ONE.

Read the study

Fortini LB, Vorsino AE, Amidon FA, Paxton EH, Jacobi JD (2015). Large-scale range collapse of Hawaiian forest birds under climate change and the need for 21st century conservation pptions. PLoS ONE 10(10): e0140389. Full text.

A version of this article appears in the forthcoming February 2016 issue of BirdWatching. Subscribe.

 

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