Extended Data Fig. 4: Hydraulic traits variation at species and community level.
From: Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests
Top panels: variation in hydraulic traits across Amazon forest types; long DSL (brown), intermediate DSL (green) and aseasonal (blue). A) xylem water potential at which 50% (\(\varPsi \)50) of the conductance is lost. B) hydraulic safety margins related to \(\varPsi \)50 (HSM50 = \(\varPsi \)dry – \(\varPsi \)50). C) minimum leaf water potential observed in the dry season (\(\varPsi \)dry). Dashed lines show the mean value of each trait across all tree taxa. Red lines denote hydraulic safety margins equal to zero. Significant differences at p < 0.05 are shown by letters above each boxplot (Kruskal–Wallis followed by post hoc Mann–Whitney–Wilcoxon Rank Sum test). Each point represents one species per site. Long DSL, intermediate DSL and aseasonal forests encompass 3, 5 and 3 forest sites, respectively. Boxplots display the 25th percentile, median and 75th percentile. The vertical bars show the interquartile range times 1.5 and datapoints beyond these bars are outliers. Bottom panels: Relationship between tree basal-area weighted mean hydraulic traits and maximum cumulative water deficit (MCWD). D) Basal area-weighted mean \(\psi \)50 (xylem water potential at which 50% of the conductance is lost); E) Basal area-weighted mean hydraulic safety margin (HSM50); F) Basal area-weighted mean minimum leaf water potential observed in the dry season (\(\varPsi \)dry); n = 11 sites. Significant linear relations are shown by regression lines and 95% confidence intervals, by shaded areas. See methods for MCWD calculations.
