The abundance change maps provide a pairwise view of a suite of combinations of current (1961-1990 baseline) conditions vs. future (2071-2100) General Circulation Models (three different models and their "average") and two emission scenarios (B1, a 'Lo'- relatively high conservation emission scenario and A1fi, a 'Hi' - keep increase fossil fuel emissions). The pull-down menus allow any combination, and the animation button allows a flashing (on/off) view between selected scenarios.
The legend shows the importance values (IV) of the species as calculated from the FIA data.
Percent Area Occupied simply is the percent of 20x20 km cells within the total area of the eastern United States that have been modeled to be suitable for the species. There are a total of 9767 cells used in the model.
Ave. IV is the average importance value across all 20x20 km cells that have been modeled to be suitable for the species.
Sum IV is the sum of importance values across all cells. Thus it is a metric that considers both the abundance and the range of the species, perhaps the best metric of overall species importance.
Future/Current IV is the ratio of change between the modeled current Sum IV and any of the GCM scenarios Sum IV.