Table 3. Local pond variables included in both the linear and piecewise regression models. Only local variables that were present in the last step of a preliminary stepwise model selection procedure (stepAIC; Venables and Ripley 2002) that included all local pond variables as well as distance to Highway 401. We only included two local variables (surface vegetation and proportion of overhanging trees) and distance to the 401 in the stepwise model for the western chorus frog. See methods for explanation.

Response Local Variables
Species Richness Pond Area,
Surface Vegetation
Wood Frog Summed Calling Surface Vegetation,
Emergent Vegetation
Western Chorus Frog Summed Calling Surface Vegetation
Spring Peeper Summed Calling pH,
Surface Vegetation
Leopard Frog Maximum Adults Conductivity, Surface Vegetation
American Toad Summed Calling pH
Gray Treefrog Summed Calling Pond Area
Green Frog Maximum Adults None