Table 2 Estimated coefficients describing the rectangular hyperbolic responses of daytime NEE to incident PAR (equation (2)) and corresponding average meteorological conditions under different air temperature (Ta), soil water content (SWC), and vapor pressure deficit (VPD) levels during the vegetation active periods of DOY 180–250 in the fenced meadow (FM) and grazed meadow (GM) from 2012 to 2013.

From: Light-intensity grazing improves alpine meadow productivity and adaption to climate change on the Tibetan Plateau

  

α

Pmax

Reday

Ta

VPD

Ts

SWC

R2

P

data volume

(mgCO2 μmolPhoton−1)

(mgCO2 m−2 s−1)

(°C)

(kPa)

(°C)

(m3 m−3)

Ta < 7

Fenced

0.000195

0.23

0.019

5.79

0.22

6.25

0.16

0.66

<0.01

215

 

Grazed

0.000326

0.25

0.011

5.62

0.20

7.13

0.18

0.58

<0.01

250

7 ≤ Ta < 10

Fenced

0.000380

0.25

0.034

8.50

0.40

10.62

0.16

0.42

<0.01

214

 

Grazed

0.000804

0.29

0.044

8.30

0.34

9.18

0.19

0.41

<0.01

384

10 ≤ Ta < 13

Fenced

0.000667

0.24

0.074

11.48

0.55

13.95

0.16

0.49

<0.01

268

 

Grazed

0.000941

0.35

0.099

11.26

0.51

11.46

0.19

0.41

<0.01

479

Ta ≥ 13

Fenced

0.000629

0.23

0.084

14.50

0.84

17.12

0.17

0.40

<0.01

205

 

Grazed

0.000947

0.34

0.125

14.59

0.85

15.27

0.19

0.39

<0.01

457

SWC < 0.13

Fenced

0.000278

0.22

0.036

8.66

0.46

12.28

0.11

0.40

<0.01

168

 

Grazed

0.000444

0.24

0.021

9.19

0.36

10.13

0.12

0.33

<0.01

82

0.13 ≤ SWC < 0.18

Fenced

0.000350

0.23

0.036

9.46

0.54

11.93

0.16

0.51

<0.01

478

 

Grazed

0.000482

0.31

0.037

10.05

0.56

11.68

0.16

0.46

<0.01

602

0.18 ≤ SWC < 0.23

Fenced

0.000500

0.20

0.034

10.88

0.44

12.30

0.19

0.53

<0.01

256

 

Grazed

0.000557

0.27

0.035

10.86

0.53

11.27

0.21

0.44

<0.01

586

SWC ≥ 0.23

Fenced

—

—

—

—

—

—

—

—

—

—

 

Grazed

0.000748

0.22

0.024

11.04

0.45

11.02

0.24

0.40

<0.01

295

VPD < 0.3

Fenced

0.000277

0.26

0.023

5.57

0.17

7.62

0.16

0.53

<0.01

270

 

Grazed

0.000484

0.29

0.017

6.52

0.18

8.24

0.19

0.45

<0.01

425

0.3 ≤ VPD < 0.6

Fenced

0.000574

0.25

0.065

10.19

0.44

11.63

0.16

0.42

<0.01

316

 

Grazed

0.001204

0.36

0.115

10.47

0.45

10.49

0.20

0.38

<0.01

578

0.6 ≤ VPD < 0.9

Fenced

0.000800

0.27

0.104

12.12

0.75

15.42

0.16

0.46

<0.01

222

 

Grazed

0.001054

0.38

0.144

12.54

0.72

13.23

0.19

0.41

<0.01

357

VPD ≥ 0.9

Fenced

0.000485

0.23

0.079

14.32

1.03

18.73

0.15

0.54

<0.01

94

 

Grazed

0.000777

0.33

0.113

15.26

1.05

16.73

0.18

0.40

<0.01

205

  1. Eq. (2) was used to fit the regression coefficients based on the observed data.
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