HOW DOES CLIMATE CHANGE INFLUENCE PARASITE PRESSURE ON BIRDS?

Climate change will impact ecosystems as abiotic factors such as temperature and humidity change. Changes in ecosystems will lead to changes in species composition as species either relocate, adapt to their new environment, or go extinct. It is only possible to make robust predictions about how climate change will influence the distribution of species if information about their natural history is known. There is, however, a gap in our knowledge about the natural history of many organisms, which makes it difficult to predict how these species will be influenced by changes in the environment. Organisms such as parasites, are understudied even though they represent a large percentage of eukaryotic biodiversity and can impact their hosts. With ectoparasites on doves and pigeons (Columbiformes), it has been found that humidity may influence their populations, with more ectoparasites being found in regions with higher humidity than in regions with lower humidity. Unfortunately, there is a sampling bias with more surveys of parasites being carried out in humid regions than arid regions.

To better understand how parasites will be influenced by climate change, I conducted surveys of ectoparasites found on birds in urban and montane Utah. The prevalence of chewing lice was 10% in the montane region and 5.6% in the urban region.
Although many of the birds sampled are common to Utah, new louse host records were found in each survey, highlighting how understudied these ectoparasites are.

For Chapter 3, faunal surveys of birds and their ectoparasitic lice were used to investigate how likely changes in humidity will influence ectoparasite pressure on birds. Louse prevalence was significantly positively correlated with humidity, and louse
abundance tended to increase with humidity. The results from this study imply that the number of lice will decrease as areas become arid and increase in areas becoming wetter. However, more surveys should be carried out in regions with lower humidity so that more robust predictions can be made on how climate change could influence ectoparasite populations.