Appendix B. Meta-analysis on grazer effects on the absolute spatial heterogeneity of algal biomass.
TABLE B1. Meta-analysis on grazer effects on the absolute spatial heterogeneity of algal biomass (LR-SD). For each factor, the results of an unweighted meta-analysis are reported with degrees of freedom (df) and heterogeneity (Q) between (b) and within (w) levels. Significance levels were sequentially Bonferroni-adjusted, bold-type indicates adjusted P (Padj) values < 0.05.
Factor |
df b |
Q b |
df w |
Q w |
P |
Padj |
Slope |
Intercept |
Habitat |
2 |
11.55 |
589 |
845.46 |
0.020 |
ns |
||
Experimental unit |
2 |
3.24 |
589 |
853.77 |
0.325 |
ns |
||
Substratum |
2 |
22.28 |
589 |
834.73 |
0.001 |
<0.01 |
||
Consumer group |
6 |
26.51 |
585 |
830.50 |
0.007 |
<0.05 |
||
Grazer biomass (log g dry mass m-2) |
1 |
7.17 |
535 |
776.23 |
0.007 |
<0.05 |
-0.15 ± 0.06 |
-0.19 ± 0.19 |
LR-B |
1 |
401.27 |
590 |
455.74 |
<0.001 |
<0.001 |
0.84 ± 0.04 |
0.08 ± 0.06 |
Duration (log days) |
1 |
0.03 |
582 |
830.18 |
0.873 |
ns |
-0.02 ± 0.11 |
-0.64 ± 0.17 |
Experiment size (log cm²) |
1 |
15.75 |
525 |
707.39 |
<0.001 |
<0.001 |
-0.22 ± 0.05 |
-0.11 ± 0.15 |
Resource supply (relative units) |
1 |
9.41 |
304 |
379.62 |
0.002 |
<0.05 |
0.59 ± 0.19 |
-1.16 ± 0.19 |
Algal biomass (relative units) |
1 |
0.96 |
411 |
575.23 |
0.327 |
ns |
-0.22 ± 0.23 |
-0.60 ± 0.07 |
TABLE B2. Meta-analysis on grazer effects on the relative spatial heterogeneity of algal biomass (LR-CV). For each factor, the results of an unweighted meta-analysis are reported with degrees of freedom (df) and heterogeneity (Q) between (b) and within (w) levels. Significance levels were sequentially Bonferroni-adjusted, bold-type indicates adjusted P (Padj) values < 0.05.
Factor |
df b |
Q b |
df w |
Q w |
P |
P adj |
Intercept |
Slope |
Habitat |
2 |
7.46 |
590 |
461.82 |
0.017 |
ns |
||
Experimental unit |
2 |
2.17 |
590 |
467.11 |
0.280 |
ns |
||
Substratum |
2 |
8.93 |
590 |
460.34 |
0.004 |
< 0.05 |
||
Consumer group |
6 |
10.02 |
586 |
459.26 |
0.045 |
ns |
||
Grazer biomass (log g dry mass m-2) |
1 |
0.16 |
536 |
437.87 |
0.679 |
ns |
0.15 ± 0.19 |
0.02 ± 0.06 |
Duration (log days) |
1 |
1.44 |
582 |
466.05 |
0.094 |
ns |
0.42 ± 0.17 |
-0.14 ± 0.11 |
Experiment size (log cm²) |
1 |
0.42 |
526 |
395.75 |
0.234 |
ns |
0.28 ± 0.15 |
-0.03 ± 0.05 |
Resource supply (relative units) |
1 |
0.59 |
304 |
215.59 |
0.441 |
ns |
0.15 ± 0.19 |
0.04 ± 0.19 |
Algal biomass (relative units) |
1 |
0.95 |
411 |
286.49 |
0.330 |
ns |
0.16 ± 0.07 |
0.22 ± 0.23 |
TABLE B3. General linear model on the effect sizes of grazing on absolute (LR-SD) and relative (LR-CV) spatial heterogeneity of algal biomass. For each factor, the F ratio, the significance level, and the contrast (for categories) or the slope (for continuous variables) are given. Bold-type indicates P values < 0.05. The last row gives the details of the final model (F ratio, P value and explained variance).
Effect size |
LR-SD |
LR-CV |
||||
Factor |
F |
P |
Contrast/Slope |
F |
P |
Contrast/Slope |
Habitat |
7.23 |
0.0009 |
lotic = lentic > coastal |
6.15 |
0.0025 |
lotic = lentic > coastal |
Experimental unit |
not included |
not included |
||||
Substratum |
19.29 |
<0.0001 |
sediment = hard > plant |
17.99 |
<0.0001 |
sediment = hard > plant |
LR-B |
124.07 |
<0.0001 |
0.88 ± 0.06 |
not applicable |
||
Consumer group |
not included |
not included |
||||
Grazer biomass |
not included |
not included |
||||
Duration |
not included |
not included |
||||
Experiment size |
not included |
not included |
||||
Resource supply |
not included |
not included |
||||
Algal biomass |
not included |
not included |
||||
Full model |
F(5;239) = 65.52; P < 0.0001; R² = 0.5694 |
F(4240) = 11.49; P < 0.0001; R² = 0.1467 |
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