Fig. 2: The results for the effect size of the diversity effect (species-mixing effect) on plant litter decomposition.
The results are based on mass loss as a measure of decomposition rate. Note that ranges of x-axis differ among the panels a–f. a Analyzed by ecosystem types for all litter types; b by ecosystem types for leaf litter; c–f by ecosystem types and climatic zones for leaf litter. Open circles and error bars represent means and the 95% confidence intervals, respectively. Number of comparisons (n), treatments (t), and studies (s) are shown. Positive values of the effect size indicate faster decomposition in mixed-species litter than mono-species litter. Vertical dotted lines are to indicate the effect size of zero. Mixed-effect meta-regression showed significant differences in the effect sizes when analyzed with ecosystem types (QM = 52.64, d.f. = 5, p < 0.0001), climate regions (QM = 13.30, d.f. = 5, p = 0.02), and both of them together (QM = 69.69, d.f. = 10, p < 0.0001) as a moderator variable(s). For a comparison by climate zones, tropical and subtropical biomes were assigned as tropics to ensure the number of studies required for the analysis. Results for data types with three and more studies are shown.
