Steve Mathews
Friday, October 17, 2008 - 9:00-9:30
The distribution of birds across the landscape is driven by biotic and abiotic components. Our understanding of how birds may respond to climate change has been advanced by our understanding of how climate shapes a species range. As our knowledge about how trees may respond to climate change advances, we can take another step towards understating how birds might respond to changes in climate and vegetation. We developed random forest models of bird species distributions in the Eastern United States in terms of climate and vegetation variables. We selected 147 representative bird species breeding within the Eastern US and generated predictive maps of their contemporary distributions. These models were then projected onto three models of climate change under high and low emissions scenarios for both climate and the projected change in tree species habitat. The resulting bird models indicate that potential suitable habitat will decrease by at least 10% for 78 to 61 species and increase for 57 to 39 within the eastern United States. These changes in habitat are characterized by northeastern directional shifts with the mean centers of the birds’ ranges moving 100-200 km depending on climate model and emissions scenario. It is important to note that these changes show considerable species specific and regional variation. Managers may be faced with unique combinations of bird habitat, making it necessary to consider objectives that include maintaining habitat for species vulnerable to projected changes and in some cases providing suitable habitat for species that may establish into the new regions.
Keywords: CLIMATE CHANGE, BIRDS, TREES, RANDOM FOREST