Warmer Weather Creeping out the Honey

The recent publication of ‘Climate Change and Pacific Islands: Indicators and Impacts’ a report developed by the Pacific Islands Regional Climate Assessment (PIRCA 2012) has been the inspiration for my recent blog posts. It has helped provide new information and reiterate previous knowledge on the effects of Climate Change in the Pacific.

Something that I found interesting and relating to my new muse – Hawaii, is the warmer weather effecting bird populations.

The warmer weather has been encouraging the population of non-native mosquitoes. These mosquitoes have been spreading avian malaria which has seriously damaged bird populations (Sehgal 2012). More than 40 mosquito species have been captured in Hawaii, six have become established, most recently in 2004 (LaPonte & Burgett, 2005). The first mosquito to arrive was in 1826 (Atkinson & LaPointe, 2009b). The malaria parasite arrived later, around 1871, with the introduction of non-native birds (Miller 2012). The southern house mosquito is the vector for avian malaria and avian pox, which was one of the first to arrive (Miller 2012). Honeycreepers have mortality rates as high as 65% to 90% after been bitten just once (Miller 2012). 

Avian malaria is a diseased caused by a species of protozoan parasites (Plasmodium) that infect birds (USGS 2005). Due to climate change and the increasing temperature in the Pacific region this malaria has been able to spread. As mosquitos are new to the Hawaii environment, the birds on the island have not evolved with natural exposure to avian malaria (USGS 2005). Hawaiian honeycreepers are extremely susceptible.

Hawaii has a wide spectrum of climatic zones and habitats. These differ in rainfall, temperature and elevation which all influence the prevalence of avian malaria (USGS 2005). Mosquitos prefer wet and low elevation environments. Therefore birds who prefer a similar habitat will be at a higher risk. Honeycreepers are amongst the most susceptible, even the ones who survive acute malaria develop chronic malaria which will last for the birds lifetime (USGS 2005).

references

Atkinson, C. T., LaPointe, D. A., Hart, P. J., Spiegel, C. S., Tweed, E. J., Henneman, C., et al. (2005). ‘Host population persistence in the face of introduced vectorborne diseases: Hawaii Amakihi and avian malaria’, Proceedings of the National Academy of Sciences, 102, 5, 1531–1536.

Miller, S. (2012) ‘Climate Change Threatens Hawaiian Forest Birds’, in Keener, V. et al (ed.) Climate Change and Pacific Islands: Indicators and Impacts, PIRCA: Island Press, 11-12