Fig. 1. Corrected intrinsic water use efficiency (IWUE_s) for C3 (small dots) and C4 (large dots) species at degraded (filled dots) and nondegraded (open dots) sites in different vegetation types along the mean annual rainfall (mm) gradient of the Northeast China Transect (NECT). Photosynthetic pathway effect on IWUE_s was detected by ANOVA (p < 0.001). Vegetation type, degradation status, and mean site annual rainfall all significantly affected IWUE_s (p < 0.01 for each).