Ecological Archives M080-021-A3

David M. Merritt, Christer Nilsson, and Roland Jansson. 2010. Consequences of propagule dispersal and river fragmentation for riparian plant community diversity and turnover. Ecology 80:609–626.

Appendix C. Generalized linear models of mean plot-scale species richness as a function of treatment, and environmental covariables.

TABLE C1. Generalized linear models of mean plot-scale species richness as a function of treatment (plots receiving wind dispersed seeds, water dispersed seeds, and a plots receiving a combination), and environmental covariables. Principal coordinates axis (PCoA) 1 represents soil moisture and PCoA 2 represents light and exposure to fluvial disturbance. Significant effects (P ≤ 0.05) are in bold typeface.


Sources of variation

Impounded reaches

Free-flowing tranquil and turbulent reaches

 

 

df

F

P

χ2/df

Pcontrast

df

F

P

χ2/df

Pcontrast

2000

                   

  Treatment

2, 67

13.8

<0.0001

0.98

<0.0001

2/127

4.3

0.02

0.94

0.004

  PCoA 1

1, 67

5.6

0.02

   

1, 127

0.3

0.6

   

  PCoA 2

1, 67

0.5

0.5

   

1, 127

0.5

0.5

   
                     

2001

                   

  Treatment

2, 67

6.2

0.003

0.96

0.0008

2, 127

0.8

0.4

0.97

0.2

  PCoA 1

1, 67

6.2

0.02

   

1, 127

0.8

0.4

   

  PCoA 2

1, 67

0.8

0.37

   

1, 127

0.8

0.4

   
                     

2002

                   

  Treatment

2, 67

2.7

0.07

0.88

0.03

2, 127

1.4

0.3

0.97

0.1

  PCoA 1

1, 67

5.9

0.02

   

1, 127

2.8

0.1

   

  PCoA 2

1, 67

0.22

0.6

   

1, 127

1.6

0.2

   
                     

2003

                   

  Treatment

2, 67

2.1

0.1

0.99

0.07

2, 127

0.06

0.9

0.92

0.96

  PCoA 1

1, 67

4.4

0.04

   

1, 127

2.6

0.1

   

  PCoA 2

1, 67

0

0.97

   

1, 127

5.6

0.02

   
                     

2004

                   

  Treatment

2, 67

1.7

0.2

1.1

0.07

2, 127

0.6

0.6

0.9

0.6

  PCoA 1

1, 67

13.8

0.0004

   

1, 127

3.7

0.06

   

  PCoA 2

1, 67

1.5

0.2

 

 

1, 127

3.8

0.05

 

 


Notes: χ2/df is Pearson χ2 divided by degrees of freedom is a measure of dispersion; χ2/df near 1 indicates good model fit. Pcontrast is the P value from a linear contrast comparing mean species richness in the wind dispersed plots to mean richness of water and wind and water dispersed plots.


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