Figure 3: Stand-level effect of diversity on carbon stocks per unit area.
From: Diversity and carbon storage across the tropical forest biome
(A) Location of clusters of forest inventory plots in South America (n = 158 plots), Africa (n = 162 plots) and Asia (n = 40 plots) (some cluster centroids are not visible due to over plotting). (B & C) Diversity metric coefficients in multiple regressions relating carbon to diversity, climate and soil. Results have been presented for (B) non-spatial (OLS) and (C) simultaneous autoregressive error (SAR) models. Bars show model-averaged parameter estimates, with error bars showing standard errors. Asterisks denote variables that were significant in the average model (P < 0.05), with the summed AICC weights of models in which a variable appears shown beneath bars (where >0.75). Taxa/stem denotes richness estimates per 300 stems. SAR models indicate that increasing species richness by 1 SD (from 86 to 151 species.ha−1) increased carbon by 1.5 Mg.ha−1 in South America, 0.2 Mg.ha−1 in Africa and 15.8 Mg.ha−1 in Asia (note only the relationship in Asia was statistically significant). Green shading in (A) shows the extent of broadleaved evergreen and fresh water regularly flooded forest classes from52. Model coefficients are given in Supplementary Table 5. Maps were created in R version 3.02 (http://www.R-project.org/)53 using base maps from maps package version 2.3–9 (http://CRAN.R-project.org/package=maps)54.
