Table 4.
Explanatory variables and units considered by linear regression models
| Variables | Units | Range | 25th percentile | 50th percentile | 75th percentile | Source |
|---|---|---|---|---|---|---|
| Stream density |
km ha−1 |
0.0011–0.021 | 0.0037 | 0.0074 | 0.011 | High Res. National Hydrograph Dataset (NHD) (USGS 2013) |
| Wetland to stream Euclidean distance | m | 55.58–3195.32 | 306.73 | 520.64 | 1215.54 | High Res. NHD (USGS 2013) |
| Lake abundance (count) |
no ha−1 |
0–0.0052 | 0.00,059 | 0.0012 | 0.0019 | National Wetland Inventory (USFWS 2010) |
| Lake areal abundance |
ha ha−1 |
0–0.92 | 0.023 | 0.054 | 0.096 | National Wetland Inventory (USFWS 2010) |
| Maximum surface water extent |
ha ha−1 |
0.0091–0.41 | 0.070 | 0.10 | 0.19 | Landsat images |
| Change in surface water extent |
ha ha−1 |
0.00,031–0.37 | 0.037 | 0.067 | 0.13 | Landsat images |
| Total wetland density |
no ha−1 |
0.0059–0.27 | 0.032 | 0.076 | 0.12 | National Wetland Inventory (USFWS 2010) |
| Total wetland areal abundance | ha ha−1 | 0.0032–0.26 | 0.040 | 0.077 | 0.12 | National Wetland Inventory (USFWS 2010) |
| Wetland to wetland Euclidean distance | m | 49.02–351.84 | 69.32 | 88.13 | 128.30 | National Wetland Inventory (USFWS 2010) |
| Percent drained by anthropogenic means | % | 0.15–60.06 | 1.85 | 3.85 | 16.78 | National Land Cover Database and Soil Survey Geographic Database (Christensen et al. 2013) |
| Elevation coefficient of variation | m | 5E−08–0.23 | 0.021 | 0.033 | 0.053 | National Elevation Dataset (NED) 10 m Digital Elevation Model (DEM) (Gesch et al. 2002) |
| Melton ruggedness number | m km2 | 0.17–3.43 | 0.38 | 0.54 | 0.83 | NED 10 m DEM ((Zmax–Zmin)/area) (Gesch et al. 2002) |
Range and percentiles are provided to show distribution of values for each variable across all hydrological units (HUC10s)