Fig 2. Final SEMs linking P_mass and P_area and their drivers.

Single headed arrows indicate a causal influence of one variable upon another. Narrow arrows indicate P < 0.05; wider arrows indicate P < 0.01; and the widest arrows indicate P < 0.001. Values on arrows indicate standardized coefficients. The value at the top-right corner of each variable (r²) represents the proportion of variance explained. Abbreviations: MAP, mean annual precipitation; TSK, total soil potassium; TSP, total soil phosphorus; LMT, leaf morphological trait; LMA, leaf mass per area; LA, leaf area; LDW, leaf dry weight; P_mass, leaf phosphorus per unit mass; P_area, leaf phosphorus per unit area.