In Hawai'i, geograpahic isolation has prevented the natural establishment of mammals, reptiles, amphibians, and many insect species, such as biting mosquitoes. Isolation has also facilitated the spectacular evolutionary radiation of Hawaiian honeycreepers from a single small flock of North American finches into more than 50 species and subspecies of endemic forest birds.
With the arrival of humans came the clearing of forests and the introduction of non-native species and their diseases. More than 40 mosquito species have been intercepted in Hawai‘i, and six have become established, most recently in 2004.
As global warming raises air temperatures, their seasonal high elevation refuge will shrink and eventually disappear. It is likely that the spread of mosquitoes and avian malaria (as well as avian pox) into the high elevations of Hawai'i will eventually lead to the extinct ion of many, perhaps all, of the honeycreepers that currently survive in these areas.
Unfortunately, the rate of warming in Hawai‘i may not give these birds enough time to develop resistance. Without human assistance, global warming combined with avian malaria may overwhelm Hawai'i honeycreepers and other forest bird species.