| Elevation |
Median elevation (m) |
| Slope |
Median slope (degrees) |
| Aspect |
Predominant aspect (N, S, E, W) |
| NDVI |
Median Normalized Digital Vegetation Index (2008) |
| Solar radiation |
Median solar radiation (watt-hours m2–1 day-1) |
| Population density |
Median human population density (number km2–1) |
| Terrain ruggedness |
Median terrain ruggedness (0–1 scale) |
| Road1 |
Distance (km) to nearest primary road |
| Road2 |
Distance (km) to nearest secondary road |
| Wind speed class |
Median wind speed class, classes 1 through 7 |
| Shrub/scrub |
Proportion of shrub/scrub (NLCD 2006) |
| Grassland/herbaceous |
Proportion of grassland/herbaceous (NLCD 2006) |
| Crop/hay |
Proportion of cultivated crops or pasture/hay (NLCD 2006) |
| Developed |
Proportion of developed (NLCD 2006) |
| Forest |
Proportion of forest (NLCD 2006) |
| Barren |
Proportion of rock/sand/clay (NLCD 2006) |
| Wetland |
Proportion of woody or emergent herbaceous wetlands (NLCD 2006) |
| Water/ice/snow |
Proportion of open water and/or perennial ice/snow (NLCD 2006) |
