TABLE 1.
Environmental covariates used to fit SDMs for plant species in the Mojave Desert
| Environmental variable | Code | Definition |
|---|---|---|
| Climate | ||
| Summer precipitation (mm) | SP | Average precipitation received from May to Oct |
| Winter precipitation (mm) | WP | Average precipitation received from Nov to April |
| Summer maximum temperature (°C) | T max | Maximum temperature of warmest month |
| Winter minimum temperature (°C) | T min | Minimum temperature of coldest month |
| Annual temperature range (°C) | T range | Average of the monthly temperature ranges (monthly maximum minus monthly minimum) |
| Annual heat/moisture index | AHM | (MAT + 10)/(MAP/1000) |
| Climatic moisture deficit | CMD | Difference between potential evapotranspiration (PET) and actual evapotranspiration (AET; Dobrowski et al., 2013) |
| Satellite metrics | ||
| NDVI amplitude | AMP | Maximum increase in canopy photosynthetic activity above the baseline averaged for the period 2003–2017 |
| NDVI maximum | MAXN | Maximum level of photosynthetic activity during the growing season averaged for the period 2003–2017 |
| Soil water stress | SWS | Mean of the Shortwave and Infrared Water Stress Index (SIWSI; Fensholt & Sandholt, 2003) from 2001–2010 (Inman et al., 2014). |
| Surface texture | ATI | Difference in mean daytime and nighttime surface temperatures for 2001–2010 (Inman et al.,2014) |
| Topography | ||
| Heat load index | HLI | Aspect/slope transformation index (McCune & Keon, 2002) representing the range in heat load from coolest (northeast slope) to warmest (southwest slope) |
| Slope (°) | Slope | Slope in degrees |
| Topographic position index | TPI | Steady‐state wetness index expressed as a function of slope and upstream contributing area |