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Table 3 Results from linear (LMM) and generalized linear (GLMM) mixed-effects models with fixed effects (fire severity, time since fire, fire severity × time since fire) and random effects (reach and collection date, not shown) for streamwater chemistry in burned watersheds of Yosemite National Park, California, USA. Streamwater was sampled from the sites between 1 and 13 years after the fire. Marginal (Rm2) and conditional (Rc2) coefficients of determination are shown for variation explained by fixed effects alone, and by both fixed and conditional effects, respectively. N/A means that R2 and denominator degrees of freedom (ddf) values are not available for GLMMs, and thus for DOC, NO3, NH4+, K+, Cl, and PO43−. Bolded P values indicate a significant effect (P < 0.05). F. aliphatics = functionalized aliphatics

From: Fire severity, time since fire, and site-level characteristics influence streamwater chemistry at baseflow conditions in catchments of the Sierra Nevada, California, USA

 

Sample size (n)

Fire severity

Time since fire

Fire severity × time since fire

R2

β1

F

ddf

P

β1

F

ddf

P

β1

F

ddf

P

Rm2

Rc2

DOC

94

−2.02

4.78

N/A

0.0006

−0.06

9.64

N/A

0.143

0.23

11.00

N/A

0.004

N/A

N/A

DON

90

−0.03

5.14

79.23

0.026

−0.004

9.03

79.18

<0.0001

0.003

4.56

79.21

0.036

0.14

0.31

TDN

94

−0.02

1.07

7.75

0.332

−0.004

5.18

7.71

0.032

0.002

0.89

7.66

0.375

0.13

0.29

Na+

94

−0.16

0.02

8.01

0.879

0.01

0.51

8.01

0.888

0.07

0.28

8.00

0.608

0.71

0.82

Ca2+

94

−1.90

0.51

8.00

0.494

−0.10

0.24

8.00

0.673

0.37

1.05

8.00

0.335

0.09

0.90

SO42+

94

1.30

1.06

7.99

0.333

0.08

0.04

7.99

0.453

−2.20

1.38

7.99

0.274

0.08

0.90

Mg2+

94

−0.87

0.48

8.00

0.507

−0.03

0.27

8.00

0.749

0.16

0.86

8.00

0.381

0.07

0.92

Cl

94

0.19

5.25

N/A

0.313

0.03

8.74

N/A

0.036

−0.04

11.57

N/A

0.105

N/A

N/A

NO3

94

0.52

0.21

N/A

0.294

−0.01

0.96

N/A

0.862

−0.06

0.95

N/A

0.331

N/A

N/A

NH4+

94

−0.09

0.05

N/A

0.842

0.01

0.38

N/A

0.755

0.02

0.11

N/A

0.722

N/A

N/A

K+

94

0.12

1.33

N/A

0.883

0.03

1.76

N/A

0.680

0.01

0.05

N/A

0.922

N/A

N/A

PO43−

94

0.56

3.21

N/A

0.504

0.03

0.38

N/A

0.677

−0.02

0.11

N/A

0.841

N/A

N/A

SUVA254

57

−1.39

3.49

9.14

0.094

−0.14

0.09

10.77

0.039

0.25

5.67

8.80

0.042

0.18

0.49

E2:E3

57

1.62

6.52

9.13

0.031

0.02

5.39

11.93

0.671

−0.25

8.05

8.63

0.020

0.18

0.44

Arom:Oxy

57

0.04

0.00

9.83

0.957

−0.01

0.11

12.73

0.864

0.05

0.28

9.30

0.608

0.04

0.24

Aromatic

57

−0.27

0.13

9.63

0.722

−0.03

0.01

12.39

0.599

0.07

0.52

9.12

0.490

0.21

0.27

Unsaturated

57

−0.48

0.68

9.87

0.430

−0.03

0.00

12.28

0.505

0.06

0.56

9.41

0.472

0.01

0.44

Oxygenated

57

−4.03

1.00

10.98

0.338

−0.25

0.00

15.48

0.477

0.48

0.72

10.21

0.415

0.019

0.024

F. aliphatics

57

1.40

0.16

53.00

0.694

0.10

0.16

53.00

0.749

−0.39

0.64

53.00

0.426

0.021

0.021

Aliphatics

57

0.74

1.35

10.33

0.272

0.04

0.00

14.59

0.487

−0.07

0.66

9.63

0.435

0.03

0.14