Figure 1.
Business-as-usual urbanization scenario for the Southeast US.
The Southeast US region used in this study. (a) EPA Level III ecoregions and initial urban extent. The 309 sub-regions (CSAs and rural county groups) used to calibrate the SLEUTH model are outlined in black. Red areas are urban extent as classified by our hybrid NLCD-TIGER dataset method (see File S1). (b) Initial urban land cover in 2009. (c) projected urban land cover in 2060. (d) projected urban land cover in Piedmont ecoregion, showing connected urban landscape.
Figure 2.
Urban sprawl examples and their representation in the input data.
Imagery in (a) and (b) document the rapid but low-density urbanization common in the Southeast US (imagery for Raleigh, NC in 1993 and 2010). (c) Road network used as basis for identifying urban areas (same area as in (a) and (b)). (d) Initial (2009) urban classification (pink shade) based on road network density and NLCD urban classification (red shade).
Figure 3.
(a) and (b) show time series of projected urbanization for 200 model simulations for the study region and twelve ecoregions, respectively. (c) The 95% projected range of the proportion of each land cover type converted to urban. (d) Change in patch metrics for all land cover types between 2009 and 2060. Ecoregion abbreviations in (b) are as follows: BR – Blue Ridge, CA – Central Appalachians, IP – Interior Plateau, MACP – Mid Atlantic Coastal Plain, MAP – Mississippi Alluvial Plain, MVLP – Miss. Valley Loess Plains, P – Piedmont, RV – Ridge and Valley, SP – Southeastern Plains, SCP – Southern Coastal Plains, SFC – South Florida Coastal Plain, SA – Southwest Appalachian.
Figure 4.
Examples of SLEUTH model output.
Individual fifty-year model simulations (2010–2060) along with the final projection based on 200 Monte Carlo simulations for two fast-growing regions: Walton County in Georgia (Figure 4a and 4b) and Wake County in North Carolina (Figure 4c and 4d). Red cells in (a) and (c) correspond to new urban growth and gold cells depict 2009 classified urban areas. Cell colors in (b) and (d) are the same as color legend in Figure 1.