Table 2. Mean and standard error of main abiotic variables in the three superclusters.
| ENVIRONM. VARIABLE | DESERT | MEDITERRANEAN | SAVANNA | F | P |
|---|---|---|---|---|---|
| Aridity Index | 0.09 ± 0.01b | 0.35 ± 0.02 a | 0.28 ± 0.01a | F(2,348) = 107.9 | <0.001 |
| Rain Seasonal. | 43.43 ± 1.03b | 27.47 ± 2.23 c | 112.15 ±1.59a | F(2,348) = 767.2 | <0.001 |
| MAP (mm) | 250.4 ± 10.4c | 400.9 ± 22.6b | 724.4 ± 16.2a | F(2,348) = 300.8 | <0.001 |
| MAT (°C) | 20.90 ± 0.13b | 16.27 ± 0.29c | 26.00 ± 0.20a | F(2,348) = 409.1 | <0.001 |
| Phosphorus (%) | 0.024 ± 0.001a | 0.023 ± 0.002a | 0.023 ± 0.001a | F(2,348) = 0.107 | 0.899 |
| Nitrogen (%) | 0.041 ± 0.001c | 0.094 ± 0.002a | 0.056 ± 0.002b | F(2,348) = 197.03 | <0.001 |
| CEC (meq/100g) | 14.21 ± 0.49a | 12.37 ± 1.06ab | 10.63 ± 0.764b | F(2,348) = 7.98 | <0.001 |
| Carbon (%) | 0.75 ± 0.02c | 1.53 ± 0.05a | 0.98 ± 0.03b | F(2,348) = 103.53 | <0.001 |
| pH (CaCl2) | 6.08 ± 0.03b | 6.49 ± 0.07a | 5.46 ± 0.05c | F(2,348) = 67.73 | <0.001 |
| AWC (%) | 14.99 ± 0.09b | 13.20 ± 0.21c | 15.72 ± 0.15a | F(2,348) = 46.30 | <0.001 |
| Sand (%) | 69.66 ± 0.80a | 72.90 ± 1.73a | 65.96± 1.23b | F(2,348) = 5.88 | 0.003 |
| Clay (%) | 18.50 ± 0.58ab | 16.42 ± 1.26b | 20.61 ± 0.90a | F(2,348) = 3.86 | 0.022 |
| Bulk Density (g/cm3) | 1.45 ±0.003a | 1.39 ± 0.007b | 1.45 ± 0.005a | F(2,348) = 33.23 | <0.001 |
| Vegetated Substrate (# IPs) | 150.5±8.3b | 246.4 ± 18.1a | 226.0 ± 12.9a | F(2,348) = 19.10 | <0.001 |
Statistical differences were tested with one-way ANOVA showing F and P values. Different letters indicate statistical significant differences between means. The complete plot dataset is displayed in S1 Table. Soil values refer to the 0–5 cm depth. Variable units as in Table 1. Aridity Index: represented in an inverse scale (high values indicate low aridity); Rain Seasonality: Coefficient of variation. MAP: Mean annual precipitation; MAT: Mean annual temperature; Nitrogen, Phosphorus and Carbon: Mass fraction of total in the soil by weight; CEC: Effective cation exchange capacity; AWC: Available water capacity; Clay & Sand percent in soil; Vegetated substrate: Number of IPs covered by vegetation.