Liu Xianfeng;Zhu Xiufang;Pan Yaozhong;Zhu Wenquan;Zhang Jinshui;Zhang Donghai;

[Liu, Xianfeng; Zhu, Xiufang; Pan, Yaozhong; Zhu, Wenquan; Zhang, Jinshui; Zhang, Donghai] Beijing Normal Univ, State Key Lab Earth Surface Proc & Resource Ecol, Beijing 100875, Peoples R China.

[Liu, Xianfeng; Zhu, Xiufang; Pan, Yaozhong; Zhu, Wenquan; Zhang, Jinshui; Zhang, Donghai] Beijing Normal Univ, Coll Resources Sci & Technol, Beijing 100875, Peoples R China.

ABSTRACT:  Daily temperature data from 1960 to 2013 and field-observed phenology data were used to investigate the spatiotemporal changes in thermal growing season and their relationship with the response of alpine grassland to climate variability in the Three-Rivers Headwater Region (TRHR) during the recent decades. We found a significant extension of the thermal growing season by 8.3 d per decade (p < 0.01) between 1986 and 2013 due to the combination of earlier start (tGSS; -4.1 d per decade, p < 0.01) and delayed end (tGSE; 4.2 d per decade, p < 0.01) of the thermal growing season. However, earlier tGSS and delayed tGSE were weakened between 2000 and 2013, compared to that between 1986 and 1999, in association with changes in seasonal temperature. Our results also suggested that earlier start of actual growing season (aGSS) was associated with the increasing winter and spring temperature; while the end of actual growing season (aGSE) was triggered by summer temperature and precipitation; and earlier and delayed of aGSE were associated with the increasing summer temperature and precipitation, respectively. Additionally, earlier tGSS was associated with an earlier aGSS response to increased temperature, while delayed tGSE was associated with earlier aGSE. Thus, the actual growing season possibly move forward rather than extended in length, in contrast to the extension of the thermal growing season due to the ongoing warming. (C) 2016 Elsevier B.V. All rights reserved.

Published in AGRICULTURAL AND FOREST METEOROLOGY.2016, 220: 30-37,

DOI: 10.1016/j.agrformet.2016.01.015