Ecological Archives E096-252-A2

Russell W. Markel and Jonathan B. Shurin. 2015. Indirect effects of sea otters on rockfish (Sebastes spp.) in giant kelp forests. Ecology 96:28772890. http://dx.doi.org/10.1890/14-0492.1

Appendix B. ANOVA tables for factors affecting juvenile rockfish growth.

Table B1. Results of linear models using first and second order terms for body size (mm) plus region (with vs. without otters) to predict (A) trophic position, (B) % kelp derived carbon, and (C) body condition of juvenile black rockfish (data shown in Fig. 6). The second order term for each predictor variable was excluded from the model whenever it or its interactions with region were nonsignificant.

 

Estimate ± SE

t value

P

       

A.  Trophic Position Posposition

  R² = 0.40

 

 

Intercept

2.80±0.01

262.0

<0.0001

Length

1.54±0.19

8.23

<0.0001

Length²

-0.11±0.18

-0.58

0.56

Region

0.13±0.02

8.30

<0.0001

Length*Region

0.51±0.31

1.68

0.09

Length*Region²

0.28±0.29

0.95

0.35

       

B.  % Kelp Carbon

R² = 0.73

 

 

Intercept

38.88±0.65

59.79

<0.0001

Length

192.04±11.38

16.88

<0.0001

Length²

-92.74±11.17

-8.30

<0.0001

Region

-3.44±0.98

-3.52

0.0005

Length*Region

24.74±18.59

1.33

0.18

Length*Region²

42.07±17.84

2.36

0.02

       

C.  Condition

R² = 0.65

 

 

Intercept

1.14±0.01

105.28

<0.0001

Length

3.46±0.19

18.21

<0.0001

Length²

0.10±0.19

0.54

0.59

Region

-0.05±0.02

-3.27

0.001

Length*Region

-1.48±0.31

-4.76

<0.0001

Length*Region²

1.03±0.30

3.47

0.0006

 

Table B2. Results from linear models testing the effects of body size (length in mm), % kelp-derived carbon, and trophic position on juvenile black rockfish growth (mean increment width) in regions with and without sea otters (data shown in Fig. 7). The second order term for each predictor variable was excluded from the model whenever it or its interactions with region were nonsignificant.

 

Estimate ± SE

t value

P

       

A.  Length

  R² = 0.53

 

 

Intercept

8.83±0.10

92.34

<0.0001

Length

7.39±0.87

8.53

<0.0001

Length²

-1.92±0.84

-2.28

0.03

Region

0.32±0.13

2.43

0.02

Length*Region

3.16±1.13

2.80

0.007

Length²*Region

-0.52±1.11

-0.47

0.64

B.  % Kelp Carbon

R² = 0.73

 

 

Intercept

6.81±0.29

23.56

<0.0001

%KDC

0.05±0.007

7.12

<0.0001

Region

-1.02±0.47

-2.19

0.03

%KDC*Region

0.04±0.01

3.16

0.002

C.  Trophic position

R² = 0.45

 

 

Intercept

-0.14±3.39

-0.04

0.97

TP

3.00±1.15

2.61

0.01

Region

-12.83±4.90

-2.62

0.01

TP*Region

4.93±1.71

2.89

0.005


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