Fig. 1.
Effect of mean annual precipitation (MAP) on Δleaf (n = 506). MAP accounts for 55% (p < 0.0001) of the variability in Δleaf in a linear regression model. Points are coded by biome: tropical rain forest (TRF), evergreen warm mixed forest (EWMF), tropical seasonal forest (TSF), cool-cold deciduous forest (CCDF), cool-cold evergreen forest (CCEF), cool-cold mixed forest (CCMF), tropical deciduous forest (TDF), xeric woodland scrubland (XWS). In a regression model using site-means (Δleaf averaged by geographic location), MAP accounts for 52% (p < 0.0001) of the variability in Δleaf (SI Appendix).