Ecological Archives E096-115-A3

Steve J. Kroiss and Janneke HilleRisLambers. 2015. Recruitment limitation of long-lived conifers: implications for climate change responses. Ecology 96:12861297. http://dx.doi.org/10.1890/14-0595.1

Appendix C. Model selection for seed and microsite limitation models.

Table C1. Factors influencing seed limitation for focal species, as determined by AIC model selection of explanatory variables explaining seed availability. We asked how basal area (parent abundance), year and their interaction influenced seed availability. Most parsimonious models are bolded, with those less than two AIC units considered equally parsimonious. Δi (AIC) = AICi – min(AIC); wi (AIC) = the rounded Akaike weights. Asterisks indicate significance levels (* = P < 0.05; ** = P < 0.01; *** = P < 0.001).

Species

Model

AICi

Δi (AIC)

wi (AIC)

Thuja plicata

Null (random effects only)

2089.9

238.4

<0.001

Basal area

2085.6

234.1

<0.001

Year

1875.9

24.4

<0.001

Basal area (***) × Year (***)

1851.5

0

1

Pseudotsuga menziesii

Null (random effects only)

1169.5

43.0

<0.001

Basal area

1165.3

38.7

<0.001

Year

1127.9

1.4

0.334

Basal area (**) × Year (*)

1126.6

0

0.666

Tsuga heterophylla

Null (random effects only)

3794.5

494.9

<0.001

Basal area

3778.8

479.2

<0.001

Year

3308.2

8.6

0.013

Basal area (***) × Year (***)

3299.6

0

0.987

Abies amabilis

Null (random effects only)

1617.4

261.6

<0.001

Basal area

1597.8

242.0

<0.001

Year

1374.9

19.1

<0.001

Basal area (***) × Year (**)

1355.7

0

1

Callitropsis nootkatensis

Null (random effects only)

768.9

41.7

<0.001

Basal area

760.1

32.9

<0.001

Year

733.3

6.2

0.043

Basal area (***) × Year (*)

727.1

0

0.957

Tsuga mertensiana

Null (random effects only)

1274.3

123.8

<0.001

Basal area

1263.2

112.7

<0.001

Year

1194.3

43.9

<0.001

Basal area (***) × Year (**)

1150.5

0

1

 

Table C2. Factors influencing microsite limitation for focal species, as determined by AIC model selection of explanatory variables explaining germination. We asked how well snowpack duration, soil moisture, canopy density and understory competitive cover influenced germination. Most parsimonious models are bolded, with those less than two AIC units considered equally parsimonious. Δi (AIC) = AICi – min(AIC); wi (AIC) = the rounded Akaike weights.

Species

Model

AICi

Δi (AIC)

wi (AIC)

Thuja plicata

Null (random effects only)

1409.9

278.9

<0.001

Snowpack duration

1381.4

250.4

<0.001

Soil moisture

1411.6

280.6

<0.001

Canopy density

1148.8

17.8

<0.001

Understory competitive cover

1406.9

275.9

<0.001

Full (all variables)

1131

0

1

Pseudotsuga menziesii

Null (random effects only)

284.4

26

<0.001

Snowpack duration

276.9

18.5

<0.001

Soil moisture

284.3

25.9

<0.001

Canopy density

262

3.6

0.147

Understory competitive cover

286.5

28.1

<0.001

Full (all variables)

258.4

0

0.853

Tsuga heterophylla

Null (random effects only)

4685.1

645.8

<0.001

Snowpack duration

4592.8

553.5

<0.001

Soil moisture

4679.3

640

<0.001

Canopy density

4191.9

152.6

<0.001

Understory competitive cover

4591.7

552.4

<0.001

Full (all variables)

4039.3

0

1

Abies amabilis

Null (random effects only)

618.5

20.6

<0.001

Snowpack duration

609.5

11.6

0.003

Soil moisture

620.6

22.7

<0.001

Canopy density

612.6

14.7

0.001

Understory competitive cover

606.8

8.9

0.011

Full (all variables)

597.9

0

0.985

Callitropsis nootkatensis

Null (random effects only)

288

9.9

0.006

Snowpack duration

288.7

10.6

0.005

Soil moisture

286.9

8.8

0.011

Canopy density

287.3

9.2

0.009

Understory competitive cover

284.6

6.5

0.035

Full (all variables)

278.1

0

0.934

Tsuga mertensiana

Null (random effects only)

915.3

221.1

<0.001

Snowpack duration

777.4

83.2

<0.001

Soil moisture

831.9

137.7

<0.001

Canopy density

884.7

190.5

<0.001

Understory competitive cover

869.3

175.1

<0.001

Full (all variables)

694.2

0

1


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