Ecological Archives E088-160-A3

Hélène Fréville, Kevin McConway, Mike Dodd, and Jonathan Silvertown. 2007. Prediction of extinction in plants: interaction of extrinsic threats and life history traits. Ecology 88:2662–2672.

Appendix C. Results of the multivariate analysis showing the effects of life history traits and extrinsic threats on extinction risk.

Results for fixed effects in the optimal general linear model, omitting terms that were dropped during fitting. Two-way interactions that also appear in three-way interactions (all with Period) are shown in parentheses. The table gives degrees of freedom (df) for the numerator and the denominator of the F statistic for testing each term in the presence of the other terms and the corresponding P value.


Term

df

F

P

Intercept

1, 2189

45.107

<.0001

Main effects

     

Threat variables

     

Nitrogen

4, 41

4.640

0.0035

Biomass

1, 41

25.442

<.0001

pH

1, 41

23.786

<.0001

Plot size

1, 41

4.974

0.0312

Life history traits

     

Mating system

2, 48

8.051

0.0010

Apomixis

1, 48

0.014

0.9072

Seed bank

1, 2189

2.027

0.1547

Diaspore weight

1, 48

0.201

0.6559

Plant height

1, 48

7.909

0.0071

Flowering duration

1, 48

5.604

0.0220

Month of earliest flowering

1, 48

9.130

0.0040

Dispersal

2, 48

3.402

0.0415

Period

1, 2189

0.731

0.3927

Two-way interactions

     

Trait × Threat interactions

     

Mating system × Nitrogen

8, 2189

3.258

0.0011

Apomixis × Biomass

1, 2189

8.792

0.0031

Apomixis × pH

1, 2189

9.567

0.0020

Seed bank × Nitrogen

4, 2189

8.738

<.0001

Seed bank × Plot size 

1, 2189

7.602

0.0059

(Diaspore weight × Biomass)

1, 2189

1.973

0.1603

(Diaspore weight × pH)

1, 2189

2.438

0.1186

Plant height × Nitrogen

4, 2189

6.451

<.0001

Plant height × Biomass

1, 2189

49.156

<.0001

(Stress tolerance × Biomass)

1, 2189

63.376

<.0001

(Flowering duration × pH)

1, 2189

0.391

0.5318

Flowering duration × Plot size

1, 2189

7.909

0.0050

Month of earliest flowering × Nitrogen

4, 2189

6.943

<.0001

Month of earliest flowering × Biomass

1, 2189

14.024

0.0002

Month of earliest flowering × Plot size

1, 2189

12.321

0.0005

(Dispersal × Nitrogen)

8, 2189

4.682

<.0001

Dispersal × pH

2, 2189

4.531

0.0109

Trait × Trait interactions

     

(Seed bank × Month of earliest flowering)

1, 2189

4.218

0.0401

(Diaspore weight × Month of earliest flowering)

1, 48

5.660

0.0214

Plant height × Month of earliest flowering

1, 48

10.301

0.0024

Stress tolerance × Ruderalness

1, 48

5.072

0.0289

Flowering duration × Dispersal

2, 48

9.993

0.0002

Period (temporal) interactions

     

Mating system × Period

2, 2189

14.168

<.0001

Diaspore weight × Period

1, 2189

0.762

0.3827

Plant height × Period

1, 2189

15.327

0.0001

(Flowering duration  × Period)

1, 2189

11.207

0.0008

Month of earliest flowering × Period

1, 2189

16.390

0.0001

(Dispersal  × Period)

2, 2189

0.676

0.5086

(Nitrogen × Period)

4, 2189

0.491

0.7422

(Biomass × Period)

1, 2189

5.457

0.0196

(pH × Period)

1, 2189

8.507

0.0036

Three-way interactions

     

Trait × Threat × Period interactions

     

Diaspore weight × Biomass × Period

1, 2189

4.559

0.0329

Diaspore weight × pH × Period

1, 2189

4.100

0.0430

Stress tolerance × Biomass × Period

1, 2189

15.600

0.0001

Flowering duration × pH × Period

1, 2189

8.356

0.0039

Dispersal × Nitrogen × Period

8, 2189

2.169

0.0271

Trait × Trait × Period interactions

     

Seed bank × Month of earliest flowering × Period

1, 2189

33.578

<.0001

Diaspore weight × Mo. of earliest Flow. × Period

1, 2189

12.534

0.0004



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