Table 2 Results of the GLMMs for the BACI experiment on infaunal and epifaunal abundance (Ab) and biomass (Bio) at the population and class or phylum level, for a continuous gradient of fishing intensity (FI).

From: Defining thresholds of sustainable impact on benthic communities in relation to fishing disturbance

Response

Fixed effects

ΔAIC

FI x Survey interaction

Survey effect

May

September

May

September

ES (%) (β3a(7a))

SE3a(7a)

p3a(7a)

ES (%) (β3b(7b))

SE3b(7b)

p3b(7b)

ES (%) (β2a)

SE2a

p2a

ES (%) (β2b)

SE2b

p2b

All infauna

(Ab)

T,D,DxS

2.9

4

0.081

0.621

9

0.083

0.294

−35*

0.244

0.075

56*

0.246

0.071

(Bio)

T

2.59

−12

0.172

0.476

4

0.176

0.808

27

0.529

0.658

30

0.533

0.625

Bivalvia

(Ab)

D,DxS

1.99

10

0.14

0.494

25

0.159

0.16

27

0.441

0.585

89

0.455

0.163

(Bio)

 

2.88

−7

0.342

0.842

32

0.345

0.429

14

1.02

0.9

65

1.024

0.627

Crustacea

(Ab)

D,DxS

−2.66

19

0.126

0.175

41*

0.133

0.01

−56*

0.397

0.038

170*

0.403

0.014

(Bio)

T,D

1.95

−17

0.138

0.185

−1

0.151

0.93

124*

0.429

0.061

244*

0.446

0.006

Echinodermata

(Ab)

 

−2.11

−34*

0.175

0.019

−28*

0.197

0.095

125

0.572

0.157

267*

0.604

0.032

(Bio)

T,D

3.19

−8

0.147

0.579

−13

0.151

0.376

−7

0.377

0.842

28

0.377

0.521

Polychaetae

(Ab)

T,D,DxS

3.13

2

0.096

0.81

9

0.098

0.373

−35

0.29

0.134

44

0.29

0.206

(Bio)

T,D

−2.44

−10

0.1

0.283

15

0.104

0.17

25

0.308

0.467

32

0.314

0.375

Sipuncula

(Ab)

 

3.12

−12

0.282

0.663

15

0.315

0.654

−35

0.867

0.623

113

0.917

0.41

(Bio)

T,TxSxFI

5.12

sd: −14

0.139

0.1

−15*

0.096

0.089

5

0.172

0.774

41*

0.172

0.048

   

gv: 4

0.077

0.616

5

0.089

0.599

      

All epifauna

(Ab)

T,TxSxFI

−10.77

sd: −6

0.064

0.369

15*

0.071

0.049

61*

0.133

<0.001

−41*

0.155

0.001

   

gv: −11*

0.057

0.034

−8

0.79

0.296

      

(Bio)

 

0.31

−9*

0.054

0.099

−2

0.061

0.789

32*

0.147

0.061

−1

0.164

0.969

Bivalvia

(Ab)

D

2.52

19

0.159

0.268

18

0.163

0.298

−15

0.43

0.715

−80*

0.438

<0.001

(Bio)

D, DxS

−9.54

32*

0.079

0.001

12

0.081

0.158

−3

0.208

0.884

−32*

0.209

0.062

Bryozoa

(Bio)

 

−2.05

−8*

0.042

0.038

−10*

0.049

0.026

14

0.115

0.265

24*

0.13

0.098

Chordata

(Ab)

D

0.56

−8

0.061

0.161

2

0.063

0.727

0

0.165

1

−40*

0.165

0.002

(Bio)

T

−5.47

−17*

0.061

0.002

−5

0.062

0.393

93*

0.221

0.003

−10

0.222

0.649

Cnidaria

(Ab)

 

−8.17

−16*

0.072

0.014

−22*

0.073

0.001

69*

0.197

0.008

9

0.2

0.655

(Bio)

 

−8.25

−18*

0.069

0.005

−21*

0.071

0.001

55*

0.187

0.021

45*

0.187

0.049

Crustacea

(Ab)

 

−3.15

−11*

0.064

0.06

4

0.066

0.507

20

0.177

0.295

−54*

0.178

<0.001

(Bio)

 

1.3

−9

0.075

0.234

2

0.077

0.763

1

0.205

0.95

−22

0.207

0.228

Echinodermata

(Ab)

T,D

−2.98

−4

0.097

0.693

25*

0.101

0.027

91*

0.265

0.015

−45*

0.265

0.023

(Bio)

T

−3.85

−2

0.08

0.813

20*

0.086

0.033

25

0.219

0.303

−9

0.229

0.685

Gastropoda

(Ab)

D,DxS

2.13

−10

0.101

0.287

2

0.102

0.845

64*

0.264

0.061

−76*

0.276

<0.001

(Bio)

D,DxS

2.58

−10

0.112

0.344

2

0.113

0.893

35

0.295

0.315

−36

0.296

0.143

  1. S = Survey time, T = Texture, D = Depth. All models include the fixed effects S, FI and SxFI, plus the effects indicated in the table. ΔAIC is the difference in AIC between models with and without the ‘time x treatment’ interaction (i.e. SxFI) -a negative value (bold) means that the model with interaction is better (i.e. significant effect of the fishing gradient). β3a(7a) and β3b(7b) are the estimates of the ‘S x FI’ interaction as in eq1 for ‘before’ to ‘after’ and ‘before’ to ‘4 months after fishing’ respectively, with corresponding standard errors (SE) and p-values (p). β2a and β2b are the estimates (with s.e. and p-values) of the survey effect alone (i.e. natural variation in time). Here we give ES, i.e. effect size equal to [exp(β)-1] * 100, instead of β, for interpretability. ES is the percentage change (in abundance or biomass) per dredge pass compared to March. ‘gv’ and ‘sd’ refer to gravel and sand where the interaction with texture was in the best model. The symbol * identifies the significant ES with α = 0.1. P. maximus and O. fragilis were excluded from the epifaunal groups.
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