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. 2007 Jun 20;104(26):10904–10909. doi: 10.1073/pnas.0701918104

Table 1.

Results of bivariate MA and GLM testing for significant impact of environmental variables on effect sizes of herbivory and fertilization and their interactive effect on richness and evenness of the producer community

Factor Effects on species richness
Effects on evenness
Herbivory Fertilization Interaction Herbivory Fertilization Interaction
Model MA GLM MA GLM MA GLM MA GLM MA GLM MA GLM
System T > F** T > M > F** F > T*** / NS / T > F*** / NS F = M > T+ NS /
Productivity (rel. units) 0.062* 0.043+ −0.038* / NS 0.081+ NS / NS 0.086** NS /
Herbivore effect biomass 0.080** / NS / NS / NS −0.081*
Fertilization effect biomass NS / −0.119** −0.217* NS / NS 0.182***
Pielou's evenness (J) −0.471** −0.445** 0.267** 0.334** 0.414* 0.435*
Species richness (ln S) −0.061* −0.148*** NS / −0.144* /
Experiment duration (ln d) 0.028** −0.126*** −0.059** −0.051*** NS / NS / NS / NS /
Experiment size (ln m2) NS / −0.036** / NS / NS / −0.034* / 0.036* 0.027*
Latitude,° N or S NS / NS / / −0.004* / NS / NS /
F ratio (d.f.) 7.46 (5;45) 16.68 (2;63) 3.53 (3;22) 11.92 (1;92) 2.30 (3;81) 9.23 (3;22)
P <0.0001 0.0024 0.0316 0.0008 0.0838 0.0004
R2 0.453 0.346 0.325 0.115 NS 0.557

For each response variable, the significant parameter estimates (NS, not significant; /, not included in the final model, –, not applicable) and their significance levels (∗∗∗, P < 0.001; ∗∗, P < 0.01; ∗, P < 0.5; +, P < 0.1; NS, P > 0.1) are given as well as overall model statistics (F ratio with degrees of freedom, significance level, and R2). rel., relative; ln, natural log.

Significant differences between terrestrial (T), freshwater (F), and marine (M) ecosystems are shown.