The multiple buffers with radii of 100, 500, 1000, 1500, 2000, and 2500 m were defined as the spatial scale.
Selected habitat characteristics were estimated for stands containing the sample points and within buffers with radii of 250, 500 m, and 1 km surrounding the sample points.
Applying the Simpson index of diversity (SID) to circular buffers with radii of 1.5 and 5 km elucidated the spatial distribution of crop diversity at both the local and landscape spatial scales.
Habitat attributes were developed from forest inventory data and other information at the stand level and in circular buffers with radii of 250, 500 m, and 1 km around each sample point.
For traffic variables, circular buffers with radii of 25, 50, 100, 300, 500, and 1,000 m around each site were calculated.
We used 2001 traffic count data from the Washington Department of Transportation to estimate annual average traffic volume on the nearest major road (federal or state highway) within circular buffers with radii of 250 and 500 m (Washington State Department of Transportation 2002).
For the city-specific model, the percentage of land use in 2006 from a 5 × 5 m grid map was calculated for circular buffers with radii of 25, 50, 100, 250, and 500 m.
The total length of roads (meters) within circular buffers with radii of 50 m, 100 m, and 200 m centered at the participants' residences were calculated using TeleAtlas MultiNet road class data (TeleAtlas 2002).
For the large-area and the city-specific LUR models, the number of inhabitants in circular buffers with radii of 100 m, 300 m, 1 km, and 5 km was calculated from the national population density database.
For 10 different categories— residential, industry, transport, port, airport, waste or construction, urban green, forest, agriculture, and combined green space (urban green, forest, and agriculture)—we calculated the percentage of land use in circular buffers with radii of 300 m, 1 km, and 5 km around the monitoring sites.
