Saturday, February 11, 2012

Goldfinches and Climate Change

The U.S. Forest Service has released two new portals for exploring their climate change database: the Climate Change Bird Atlas and the Climate Change Tree Atlas. These portals give some idea of how species might react to climate change under different warming scenarios. These are should be taken as estimates; some species will adapt better than predicted to changing conditions while others will probably have a harder time. I saw the tree atlas first in a blog post at Weather Underground, which feared the potential for buckeyes to invade Ann Arbor. I learned of the bird atlas through a post by Julia Whitty at the Blue Marble blog at Mother Jones.

Her blog post highlighted the changes that would occur in the range of the American Goldfinch, currently a very common species in the northern United States. Under high warming and emissions scenarios, its range would change drastically from the present one and become more common in southern Canada than in the northern U.S. In her words, "the 'Canadian goldfinch' could be set to become the iconic provincial bird of Quebec, New Brunswick, and Ontario." New Jersey's state bird would go from being very common to relatively uncommon and perhaps only a seasonal visitor in some parts of the state. The potential change is eye-opening, to say the least. If goldfinches could decline here so readily, how many other species would we lose entirely in the state?

Some bird species will no doubt become more common at the same time. One species that might become common here is Painted Bunting, which is now an occasional visitor to the state (maybe one or two sightings a year). The Painted Bunting maps are shown below. Other species that could arrive here under the Forest Service models include Loggerhead Shrike and Scissor-tailed Flycatcher.

I post these maps because they show the potential changes in species abundance rather dramatically. While I would certainly enjoy seeing Painted Buntings and Scissor-tailed Flycatchers on a regular basis, these sorts of changes will no doubt be stressful for many species and possibly put some of the rarer ones at risk of extinction. For that reason, I would prefer that these scenarios not come to pass.