“…However, the considerable difference in the timing of earliest greening in 2013 and 2014 (beginning of May) versus 2015 (beginning of June), in combination with the clear decline in temperature sensitivity in 2015, indicated that day length was not the main driver of the SOS in these subarctic grasslands. Precipitation can play a role in SOS of subarctic and alpine grasslands, although its effect is not consistent, varying between nonexistent (Piao et al., ), positive (Fu, Piao, et al., ), negative (Chen et al., ; Sha, Zhong, Bai, Tan, & Li, ), and dependent on the specific situation (Shen, Piao, Cong, Zhang, & Janssens, ; Shen, Tang, Chen, Zhu, & Zheng, ; Zhang, Yi, Kimball, Kim, & Song, ). In this study, no major variation in soil water status occurred along the temperature gradients (Sigurdsson et al., ), especially in early spring, so it is unlikely that precipitation was an important determinant of the decelerating advance of SOS.…”