• Current Distribution Maps
• Climate Change Scenario Maps
• Predictor Maps

Current Distribution Maps

The legend shows the incidence values (IV) of the species as calculated from the North America Breeding Bird Survey data (BBS). The BBS Incidence (on a scale of 0 – 1) represents the proportion of times a species was observed on a route over a decade. The value is the bases for modeling and projecting bird incidence across the eastern US.

Climate Change Scenario Maps

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 incidence values (IV) of the species as calculated from the North America Breeding Bird Survey data (BBS). The BBS Incidence (on a scale of 0 – 1) represents the proportion of times a species was observed on a route over a decade. The value is the bases for modeling and projecting bird incidence across the eastern US.

Potential Changes in Abundance and Range (Future)

Percent Area Occupied

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

The average importance value (IV) across all 20x20 km cells that have been modeled to be suitable for the species.

Sum IV

The sum of importance values (IV) 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

[Only applies to Projected Future Habitat] The ratio of change between the modeled current Sum IV and any of the GCM scenarios Sum IV.

Predictor Maps

These maps are tied to the tree diagram for the 38 model variables, which drive the distribution of a species. The 38 variable are divided into five categories including Climate (7), Soil Properties (12), Soil Types (9), Elevation (5), and Landscape (5). Due to the nature of the non-climatic variables, the seven climate variables were only mapped for each scenario to compare the differences in the models. Within the Climate tab, two maps have been provided so that a comparison can be made by selecting two models. Maps are based on a 20 x 20km grid of cells that make up the extent of the United States east of the 100th Meridian. The scale is 1:33,000,000 and is projected in Clarke 1866 Albers.

Climate

The climate will be affected by the emission levels of each scenario, and the results of nine models have been included for each variable. The legend contains the temperature in degrees Celsius; the scale for the current climate differs slightly from the other scenarios which all have the same temperature scale.

Mean Annual Temperature (°C)

average annual temperature for the counties occupied by the species. Data from USEPA (1993).

Mean January Temperature (°C)

average January temperature for the counties occupied by the species. Data from USEPA (1993).

Mean July Temperature (°C)

average July temperature for the counties occupied by the species. Data from USEPA (1993).

Mean May-September Temperature (°C)

Annual Precipitation (mm) - average annual precipitation for the counties occupied by the species. Data from USEPA (1993).

Mean May-September Precipitation (mm)

Total monthly precipitation from May to September

Mean Difference between July and January Temperature (°C)

measure of seasonality and here the differences between July and January monthly mean temperature.

Elevation

Maximum Elevation (m)

average maximum elevation for the counties occupied by the species. Data from USGS 1:250,000 Digital Elevation Model (DEM) files.

Minimum Elevation (m)

average minimum elevation for the counties occupied by the species. Data from USGS 1:250,000 Digital Elevation Model (DEM) files.

Mean Elevation (m)

For each cell the average elevation from the maximum and minimum elevation

Range of Elevation (m)

For each cell the difference in Maximum and minimum Elevation

Tree species

Importance values from the tree species portion of the atlas were included as predictor variables. Thus they influence they are important in developing the model and like the climate variables the project changes in tree habitat will also influence the projected changes in bird habitat. We selected 39 of the 134 possible tree species base on initial model runs (see Matthews et al. 2011 for details).

• IV12: balsam fir (Abies balsamea) 
• IV71: tamarack (native) (Larix laricina) 
• IV95: black spruce (Picea mariana) 
• IV97: red spruce (Picea rubens) 
• IV105: jack pine (Pinus banksiana) 
• IV110: shortleaf pine (Pinus echinata) 
• IV111: slash pine (Pinus elliottii) 
• IV126: pitch pine (Pinus rigida) 
• IV129: eastern whitepine (Pinus strobus) 
• IV131: loblolly pine (Pinus taeda) 
• IV132: Virginia pine (Pinus virginiana) 
• IV222: pondcypress (Taxodium distichum var. nutans) 
• IV241: northern white-cedar (Thuja occidentalis) 
• IV261: eastern hemlock (Tsuga canadensis) 
• IV315: striped maple (Acer pensylvanicum) 
• IV316: red maple (Acer rubrum) 
• IV318: sugar maple (Acer saccharum) 
• IV371: yellow birch (Betula alleghaniensis) 
• IV372: sweet birch (Betula lenta) 
• IV375: paper birch (Betula papyrifera) 
• IV408: black hickory (Carya texana) 
• IV462: hackberry (Celtis occidentalis) 
• IV491: flowering dogwood (Cornus florida) 
• IV531: American beech (Fagus grandifolia) 
• IV541: white ash (Fraxinus americana) 
• IV543: black ash (Fraxinus nigra) 
• IV611: sweetgum (Liquidambar styraciflua) 
• IV621: yellow-poplar (Liriodendron tuliperfia) 
• IV693: blackgum (Nyssa sylvatica) 
• IV746: quaking aspen (Populus tremuloide) 
• IV762: black cherry (Prunus serotina) 
• IV802: white oak (Quercus alba) 
• IV806: scarlet oak (Quercus coccinea) 
• IV827: water oak (Quercus nigra) 
• IV832: chestnut oak (Quercus prinus) 
• IV833: northern redoak (Quercus rubra) 
• IV835: post oak (Quercus stellata) 
• IV838: live oak (Quercus virginiana) 
• IV972: American elm (Ulmus americana)

The gray shaded portions of the maps (No Data on legends) had no forest information available, due to one or more of the following: (1) there were no data recorded for any tree species for those counties (e.g., prairie states in the western part of the region), (2) one or more of the four FIA regions (northeastern, north central, southeast, southern) did not report the species in their data base because it was not present in the region (e.g., distinctly northern or southern species), and (3) one or more of the FIA regions do not recognize a particular species name as present in the unit, even though it undoubtedly is present but called something else (e.g. taxonomic confusion like in the hickories (Carya sp.)).