Table 2.
Climate and landscape variables included for initial consideration in the zero-inflated negative binomial (ZINB) model
| ZINB model variable | Correlated variable(s) |
|---|---|
| Mean diurnal range (mean of monthly (max temp − min temp)) | Average vapor pressure (summer) |
| Average vapor pressure (annual) | |
| Temperature annual range | Temperature seasonality (standard deviation × 100) |
| Mean temperature of the driest quarter | |
| Min temperature of the coldest month | |
| Precipitation of the driest month | |
| Precipitation seasonality (coefficient of variation) | |
| Precipitation of the driest quarter | |
| Precipitation of the coldest quarter | |
| Annual precipitation accumulation | |
| Average vapor pressure (annual) | |
| Average vapor pressure (winter) | |
| Average vapor pressure (fall) | |
| Mean temperature of wettest quarter | Annual mean temperature |
| Mean temperature of the driest quarter | |
| Average vapor pressure (summer) | |
| Min temperature of the coldest month | |
| Precipitation of the driest month | |
| Growing degree days (1 January–30 June) | |
| Soil water depletion (annual) | |
| Average vapor pressure (annual) | |
| Average vapor pressure (winter) | |
| Average vapor pressure (spring) | |
| Average vapor pressure (fall) | |
| Precipitation of wettest quarter | Annual precipitation |
| Precipitation of the wettest month | |
| Precipitation of the warmest quarter | |
| Annual precipitation accumulation | |
| Average vapor pressure (spring) | |
| Average vapor pressure (fall) | |
| Elevation* | Isothermality |
| Max temperature of the warmest month | |
| Mean temperature of the coldest quarter | |
| Distance (m) to the nearest stream or river corridor (m) | |
| Percent of agricultural land cover within 5.25 km2 buffer | |
| Percent of forest land cover within 5.25 km2 buffer |
Pearson’s correlation coefficient was calculated for all pairs of variables and highly correlated variables (correlation coefficient > 0.75) were represented by a single variable in the model.
*
National Elevation Dataset; https://lta.cr.usgs.gov/NED, last visited October 2014.