"This could have a tremendous adverse effect on the continued existence of high-elevation disease refugia," said Atkinson. "Remaining bird populations could be squeezed between expanding disease transmission from lower elevations and the upper limits of suitable forest habitat. 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."
Given the likelihood of global warming, the authors suggested that management of mid-elevation habitats to reduce disease transmission will become increasingly vital. The best opportunities for doing this, they wrote, will be through reducing habitat for mosquito larvae, habitat that is often created by introduced feral pigs, goats and cattle in forests.
"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," Atkinson said.
Honeycreepers rival Darwin's finches in the Galapagos Islands in terms of their bill types and number of species that descended from a common founder. The birds specialize on food that includes nectar, fruits and insects. Before people came to the islands, as many as 56 kinds of honeycreepers probably occurred.
Avian malaria is caused by a protozoan parasite, and avian pox is a viral infection that typically causes tumor-like swellings on exposed skin of the feet, legs, beak and eyelids of infected birds. Malaria often results in appetite and weight loss, anemia, and massive enlargement of birds' liver and spleen.
|Contact: Carter Atkinson|
United States Geological Survey