Ecological Archives A025-057-A1
Emily K. Read, Vijay P. Patil, Samantha K. Oliver, Amy L. Hetherington, Jennifer A. Brentrup, Jacob A. Zwart, Kirsten M. Winters, Jessica R. Corman, Emily R. Nodine, R. Iestynwoolway, Hilary A. Dugan, Aline Jaimes, Arianto B. Santoso, Grace S. Hong, Luke A. Winslow, Paul C. Hanson, and Kathleen C. Weathers. 2015. The importance of lake-specific characteristics for water quality across the continental United States. Ecological Applications 25:943–955. http://dx.doi.org/10.1890/14-0935.1
Appendix A. Model and predictor variable descriptions. Combined, regional, basin, buffer, and lake-specific scale models and categories of predictor variables included and complete list of predictor variables used, ordered by category, and data sources.
Table A1. Description of spatial models and sub-models, and the variables included in each model.
Model |
Predictor variable category |
Combined (all scales) |
Percent cover basin and buffer |
Lake-specific variables |
|
Road variables basin and buffer |
|
Regional variables |
|
Topography basin and buffer |
|
Regional |
Regional variables |
Basin |
Percent cover basin |
Road variables basin |
|
Topography basin |
|
Buffer |
Percent cover buffer |
Road variables buffer |
|
Topography buffer |
|
Lake-specific |
Lake-specific variables |
Table A2. Description of predictor variables, ordered by spatial scale, and relevant data sources.
Predictor variable category |
Predictor variable |
Data source |
Percent cover basin and buffer |
Percent open water |
EPA NLA 2007 |
Percent perennial ice or snow |
EPA NLA 2007 |
|
Percent open water + perennial ice or snow |
EPA NLA 2007 |
|
Percent developed open space |
EPA NLA 2007 |
|
Percent developed low intensity |
EPA NLA 2007 |
|
Percent developed medium intensity |
EPA NLA 2007 |
|
Percent developed high intensity |
EPA NLA 2007 |
|
|
Percent total developed |
EPA NLA 2007 |
|
Percent barren land |
EPA NLA 2007 |
Percent deciduous forest |
EPA NLA 2007 |
|
Percent coniferous forest |
EPA NLA 2007 |
|
|
Percent mixed forest |
EPA NLA 2007 |
Percent total forest |
EPA NLA 2007 |
|
Percent shrub or scrub |
EPA NLA 2007 |
|
Percent grassland |
EPA NLA 2007 |
|
Percent pasture or hay |
EPA NLA 2007 |
|
Percent cultivated crops |
EPA NLA 2007 |
|
Percent agriculture (pasture + crops) |
EPA NLA 2007 |
|
Percent woody wetland |
EPA NLA 2007 |
|
Percent emergent herbaceous wetland |
EPA NLA 2007 |
|
Percent wetland (woody + herbaceous) |
EPA NLA 2007 |
|
Lake-specific variables |
Lake area |
EPA NLA 2007 |
Lake perimeter |
EPA NLA 2007 |
|
Maximum depth (m) |
EPA NLA 2007 |
|
Sediment to epilimnetic volume ratio |
Derived from EPA NLA 2007 and Carpenter 1989 |
|
Watershed area |
EPA NLA 20007 |
|
Ratio of watershed area to lake area |
Derived from EPA NLA 2007 |
|
Shoreline development index (lake perimeter / 2 * sqrt(lake area * pi)) |
EPA NLA 2007 |
|
Elevation (m) |
EPA NLA 2007 |
|
|
Lake perimeter to lake area ratio |
Derived from EPA NLA 2007 |
X-coordinate from Albers projection (m) |
EPA NLA 2007 |
|
Y-coordinate from Albers projection (m) |
EPA NLA 2007 |
|
Residence time (days) |
McDonald et al. 2013 |
|
Road variables basin and buffer |
Mean percent impervious |
National Land Cover Dataset 2006 |
Road length (km) |
After Pechenick et al. 2014 and with TIGER/Line (2012) data set |
|
|
Road density (road length / area) |
After Pechenick et al. 2014 and with TIGER/Line (2012) data set |
Mean minimum distance between lake edge and nearest road (m) |
After Pechenick et al. 2014 and with TIGER/Line (2012) data set |
|
Regional variables |
Omernik Level II |
EPA NLA 2007 |
Nutrient ecoregions |
EPA NLA 2007 |
|
Topography basin and buffer |
Elevation standard deviation (m) |
Digital Elevation Model (1 arc-second resolution) |
Elevation range (maximum elevation - minimum elevation) (m) |
Digital Elevation Model (1 arc-second resolution) |