Ecological Archives E090-009-A3

Kristoffer Hylander. 2009. No increase in colonization rate of boreal bryophytes close to propagule sources. Ecology 90:160–169.

Appendix C. Test statistics for environmental variables.

TABLE C1. Test statistics for environmental variables within the young stands (N = 23). The z-value is the test statistics in GLM with poison and binomial error terms, t-value in GLM with Gaussian error term (linear model), and V denotes the test statistics in Wilcoxon signed rank test used for the pairwise comparison of variables in two plots (at 10 and 80 m from the edge) for variables with problematic distributions (See also Table 1).

 Variable

Error term
in GLM

Test
statistics

β

P value

Residual
deviance

df

Coarse logs (>25 cm) (m)

Poission

z = 2.8

0.74

0.0041

30

68

Fine logs (<25 cm) (m)

Poission

z = –3.0

–0.78

0.0024

51

68

Coarse stumps (>25 cm) (n:o)

Poission

z = 1.1

0.011

0.26

92

68

Fine stumps (<25 cm) (n:o)

Poission

z = 0.67

0.071

0.51

98

68

Boulders (>0.5 m) (frequency 0-20)

Binomial

z = 2.6

0.21

0.010

91

68

Dry ground (frequency 0–20)

Binomial

z = 2.2

0.026

0.025

79

68

Peatmoss cover (frequency 0–20)

Binomial

z = –1.2

–0.15

0.23

128

68

Canopy cover (%)

 

V = 17

0.086

Shrub cover (%)

 

V = 71.5

0.53

Understory cover (%)

 

V = 47.5

0.92

Bryophyte cover (%)

 

V = 87.5

0.029

Basal area spruce (m2/ha-1)

 

V = 116

1.0

Basal area pine (m2/ha-1)

 

V = 84

0.28

Basal area decidous trees (m2/ha-1)

 

V = 1

0.058

Height of trees (m)

Gaussian

t = –0.32

–0.05

0.28

67


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