Table 2.
The 21 predictor variables included in this study
| Variable number | Data source | Variable name | Variable interpretation |
|---|---|---|---|
| 1 |
|
Bio1 |
Mean temperature |
| 2 |
|
Bio2 |
Diurnal temperature range |
| 3 |
|
Bio4 |
Temperature seasonality |
| 4 |
|
Bio5 |
Maximum temperature of warmest month |
| 5 |
|
Bio6 |
Minimum temperature of coldest month |
| 6 |
WorldClim database |
Bio12 |
Annual precipitation |
| 7 |
|
Bio15 |
Precipitation seasonality |
| 8 |
|
Bio16 |
Wet season precipitation |
| 9 |
|
Bio17 |
Dry season precipitation |
| 10 |
|
Bio18 |
Precipitation of warmest quarter |
| 11 |
|
Bio19 |
Precipitation of coldest quarter |
| 12 |
|
NDVImax |
Maximum vegetation production |
| 13 |
MODIS satellite spectroradiometer |
NDVImean |
Mean vegetation production |
| 14 |
|
NDVIsd |
Vegetation seasonality |
| 15 |
QuickScat active radar scatterometer |
Qscatmean |
Mean surface moisture |
| 16 |
|
Qscatsd |
Surface moisture seasonality |
| 17 |
Shuttle Radar Topography Mission |
Elevation |
|
| 18 |
MODIS satellite spectroradiometer |
Percent tree cover |
|
| 19 |
|
Geographic distance |
|
| 20 |
GPS |
Carpentarian barrier |
|
| 21 | Eastern contact zone |
We considered the influence of 18 environmental variables, geographic distance, the Carpentarian Barrier, and the eastern contact zone on phenotypic variation. Variable numbers are referred to in Table 1.