Supplement materials

Supplement Table 1 Multivariate analysis of variance for different ecosystems on the daily basis.

Source / DF / SS / MS / F / P
Temperate forest
Taa / 12 / 12.55 / 1.05 / 9.72 / 0.00
VPD / 4 / 0.46 / 0.11 / 1.06 / 0.38
LAI / 10 / 1.37 / 0.14 / 1.27 / 0.25
CO2 / 5 / 0.91 / 0.18 / 1.68 / 0.14
SWC / 9 / 3.55 / 0.39 / 3.66 / 0.00
Error / 189 / 20.33 / 0.11
Total / 229 / 128.59
Subtropical forest
Ta / 10 / 3.03 / 0.30 / 2.96 / 0.00
VPD / 4 / 0.61 / 0.15 / 1.50 / 0.20
LAI / 3 / 1.06 / 0.35 / 3.45 / 0.02
CO2 / 4 / 0.32 / 0.08 / 0.78 / 0.54
SWC / 7 / 3.60 / 0.51 / 5.03 / 0.00
Error / 337 / 34.47 / 0.10
Total / 365 / 62.16
Temperate grassland
Ta / 11 / 3.35 / 0.30 / 5.52 / 0.00
VPD / 5 / 0.74 / 0.15 / 2.70 / 0.02
LAI / 2 / 1.01 / 0.51 / 9.20 / 0.00
CO2 / 7 / 1.27 / 0.18 / 3.30 / 0.00
SWC / 4 / 0.06 / 0.02 / 0.29 / 0.89
Error / 182 / 10.04 / 0.06
Total / 211 / 43.11
Alpine meadow
Ta / 6 / 3.76 / 0.63 / 17.12 / 0.00
VPD / 2 / 2.99 / 1.50 / 40.86 / 0.00
LAI / 6 / 2.76 / 0.46 / 12.55 / 0.00
CO2 / 4 / 0.36 / 0.09 / 2.47 / 0.05
SWC / 6 / 0.63 / 0.11 / 2.89 / 0.01
Error / 157 / 5.75 / 0.04
Total / 181 / 90.64

DF, degree of freedom; SS, sum of squares; MS, mean square; F, statistical test; P, probability; Ta, air temperature; VPD, vapor pressure deficit; LAI, leaf area index; CO2, concentration of CO2; SWC, soil water content at 10 cm depth, %; The abiotic(Ta, VPD, LAI, CO2 and SW) and biotic (LAI ) factors are taken as group variables by bin separation. Bin width is 2 ℃ for Ta, 0.25 kpa for VPD, 0.4 m2 m-2 for LAI, 20 mg L-1 for CO2, 0.02 m3 m-3 for SW, respectively.

aBold variable indicates significant factors (p<0.0001)

Supplement Fig. 1 The relationship between WUE and soil water content (SW) in typical ecosystems, and WUE is the abbreviation of water use efficiency.

Supplement Fig. 2 The relationship between WUE and leaf area index (LAI) in typical ecosystems, and WUE is the abbreviation of water use efficiency.

Supplement Fig. 3 Seasonal dynamics of T/ET in typical ecosystems, data used here are the average value of each Julian day from 2003 to 2008, and errorbar indicates the variations among years. Five days average is used to show here to be clear. T and ET are the abbreviation of transpiration and evaportranspiration.

Note：a: Temperate Forest; b: Subtropical Forest; c: Temperate Grassland; d: Alpine meadow.