Ecological Archives E085-096-A3

Mark C. Urban. 2004. Disturbance heterogeneity determines freshwater metacommunity structure. Ecology 85:2971–2978.

Appendix C. Results from nested subset, fourth-corner, and functional composition analyses.

Table C1. Results from nested subset analysis and fourth corner statistics using the random (1) permutation model. The d statistic measures within-group homogeneity while the r statistic expresses the correlation between traits and environmental variation. Note that d and r statistics for fourth corner statistics were evaluated only if global F statistics were significant. 

 
Trophic level
Dispersal
Global F statistic

F = 0.01

P = 0.914

F = 2.19

P = 0.385

Trait class
Predators
Non-predators
Active
Passive
Statistic

d = 0.47

P = 0.120

r = 0.01

P = 0.481

d = 0.53

P = 0.893

r = - 0.01

P = 0.481

d = 0.68

P = 0.022

r = 0.10

P = 0.046

d = 0.31

P = 0.970

r = - 0.10

P = 0.046

 

 

Table C2. Functional composition of pond taxa in relation to the composition of the local species pool and permanence.

Functional groups

Proportion in local species pool

Pond mean ± SD

Departure from local species pool

Relationship to  permanence

Percent predators

0.50

0.54 ± 0.17

NS

NS

Percent non-predators

0.50

0.46 ± 0.17

NS

NS

Percent active dispersers

0.77

0.72 ± 0.21

NS

NS

Percent passive dispersers

0.23

0.28 ± 0.21

NS

NS

Predator : prey taxa

1.02

1.10 ± 0.49

NS

NS

Loge-density predators: density  non-predators

0.51

0.51 ± 0.26

NS

NS



[Back to E085-096]