Table 1 Environmental variables used for species distribution modeling (see electronic supplementary file S2).

From: Landscape limits gene flow and drives population structure in Agassiz’s desert tortoise (Gopherus agassizii)

Variable (abbrev.)

Ecology

Units

Value range

Source

Elevation (elev)

Topography

m

(−74.91, 4066.31)

ASTER GDEM

Slope (slope)

Topography

radians

(0, 0.52)

terrain function in R package raster

Absolute depth to bedrock (d2b)

Soil

cm

(0.00, 65155.67)

SoilGrids106

Bulk density of fine earth (bd)

Soil

kg/m3; depth: 30 cm

(1037.29, 1749.79)

SoilGrids

Coarse fragment volume (cfv)

Soil

percent (%); depth: 30 cm

(0.00, 62.11)

SoilGrids

Wettest quarter mean temperature (Nov–Jan) (bio8)

Climate

°C

(−7.96, 33.20)

WorldClim v2107

Driest quarter mean temperature (April–June) (bio9)

Climate

°C

(−4.17 33.01)

WorldClim v2

Wettest quarter mean precipitation (Nov–Jan) (bio16)

Climate

mm

(19.0, 556.3)

WorldClim v2

Driest quarter mean precipitation (April–June) (bio17)

Climate

mm

(0.00, 116.55)

WorldClim v2

Vegetation coverage during the summer (June 2006) (vegS)

VegetationS

NDVI

(−0.20, 0.86)

eMODIS

Vegetation coverage during the winter (Feb 2005) (vegW)

VegetationW

NDVI

(−0.19, 0.93)

eMODIS

  1. Elevation and vegetation data were downloaded from https://earthexplorer.usgs.gov; soil data were downloaded from https://www.soilgrids.org; and climate data was downloaded from http://www.worldclim.org. ASTER: Advanced Spaceborne Thermal Emission and Reflection Radiometer, GDEM: Global Digital Elevation Map, eMODIS: EROS Moderate Resolution Imaging Spectroradiometer, NDVI: Normalized Difference Vegetation Index.