Fig. 2: Distribution of optimum soil moisture for gross primary productivity (\({{\rm{SM}}}^{{\rm{GPP}}}_{{\rm{opt}}}\)) derived from FLUXNET sites.
From: Evidence for the acclimation of ecosystem photosynthesis to soil moisture
a Location of the 108 sites used in this study with detected \({{\rm{SM}}}^{{\rm{GPP}}}_{{\rm{opt}}}\). The original map is from spData package in R. b Response of gross primary productivity (GPP, ln-scaled) to daily soil moisture at the 10 sites from 10 different vegetation types. The solid curve indicates the fitting of concave quadratic model, and the dotted line represents the detected \({{\rm{SM}}}^{{\rm{GPP}}}_{{\rm{opt}}}\). Site name is shown in parentheses after each vegetation type. The vegetation types are as follows: CRO, croplands; CSH, closed shrublands; DBF, deciduous broadleaf forests; EBF, evergreen broadleaf forests; ENF, evergreen needle-leaf forests; GRA, grasslands; MF, mixed forests; OSH, open shrublands; SAV, savanna; WSA, woody savanna. ***, P ≤ 0.001; **, P ≤ 0.01; *, P ≤ 0.05.
