Figure 1. The location of sites occupied by any bullfrog life stage (dark diamonds on maps) in 2005 (A), 2010 (B), 2012 (C) and 2013 (D) in the Yellowstone River region near Billings, MT. The Yellowstone River flows southwest to northeast.
By Northern Rocky Mountain Science Center
2014 (approx.)
Sources/Usage
Public Domain.