Ecological Archives E091-195-A4

Jennifer G. Howeth and Mathew A. Leibold. 2010. Species dispersal rates alter diversity and ecosystem stability in pond metacommunities. Ecology 20:2727–2741.

Appendix D. Analysis of the spatial stability (CV) of plankton biomass and ecosystem productivity as a function of dispersal rate.

TABLE D1. Effects of planktonic dispersal rate on the spatial coefficient of variation (CV) of zooplankton biomass, phytoplankton biomass, and ecosystem productivity in pond metacommunities, as analyzed with repeated measures ANOVA.

 

Response variable

df

SS

F

P value

Contrasts

Zooplankton

Dispersal

2

0.12

0.38

0.693

 

Time†

11

1.30

1.96

0.107

 

Time × disp†

22

1.07

0.80

0.623

 

Phytoplankton

Dispersal

2

3.76

6.22

0.020

[C, L↑*], [C, H↑‡]

Time

6

0.60

0.85

0.535

 

Time × disp

12

2.38

1.68

0.097

 

Ecosystem productivity

Dispersal

2

347.22

3.12

0.093

 

Time†

11

2046.08

3.31

0.102

 

Time × disp†

22

3851.88

3.11

0.094

 

† Greenhouse-Geisser-modified probability values

For zooplankton and ecosystem productivity, probability values from final 7 wk of the experiment are noted in parenthesis, if the significance level is different from the 12 wk analysis.

Post hoc pairwise contrasts (Tukey’s HSD) reported for significant main effects. Contrasts notation, dispersal: C = closed (no dispersal); L = low dispersal; H = high dispersal. Contrasts significance levels: ‡, marginally significant P < 0.08; *, P < 0.05; **, P < 0.01; ***, P < 0.001; ↑, greater CV value. For zooplankton and ecosystem productivity, 7 wk contrasts results are noted in parentheses if different from the 12 wk analysis.


 

TABLE D2. Effects of planktonic dispersal rate on the spatial coefficient of variation (CV) of zooplankton and phytoplankton functional group biomass in pond metacommunities, as analyzed with repeated measures ANOVA.

 

Response variable

df

SS

F

P value

Prey zooplankton

Dispersal

2

0.21

0.22

0.807

Time†

11

1.33

1.15

0.349

Time × disp†

22

2.51

1.09

0.374

Non-prey zooplankton

Dispersal

2

0.04

0.10

0.902

Time†

11

1.20

1.77

0.154

Time × disp†

22

1.39

1.03

0.433

Edible phytoplankton

Dispersal

2

0.0001

0.03

0.968

Time

6

0.01

1.48

0.203

Time × disp

12

  0.01

  1.18

0.319

Inedible phytoplankton

Dispersal

2

  4.73

  1.37

0.302

Time†

6

6.54

0.92

0.376

Time × disp†

12

10.15

0.71

0.533

† Greenhouse-Geisser-modified probability values

For zooplankton, probability values from final 7 wk of the experiment are noted in parenthesis, if the significance level is different from the 12 wk analysis.


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