Acta Geographica Sinica ›› 2017, Vol. 72 ›› Issue (7): 1151-1162.doi: 10.11821/dlxb201707002

• Orginal Article • Previous Articles     Next Articles

Spatial and temporal response and its causes of the growing season of Populus Euphratica to global warming in China's oases during 1960-2015

Wenxia ZHANG, Puxing LIU, Qingrong FENG, Tianguang WANG, Tianqiang WANG   

  1. College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
  • Received:2016-11-28 Revised:2017-03-21 Online:2017-08-07 Published:2017-08-07
  • Supported by:
    The Science Technology and Project of Gansu Province, No.0803RJZA094]

Abstract:

Based on the daily average temperature of 48 meteorological stations in Chinese oases of the distribution area of Populus euphratica, we analyzed spatio-temporal response of the onset and upset date of P. euphratica, and the dates of growing season to climate change, with the aid of methods including a multi-year trend line, Mann-Kendall mutation test, IDW under the ArcGIS software, Morlet wavelet power spectrum, and correlation analysis. The results indicate that in the past 56 years, the onset date of the growing season has advanced and the upset date has postponed; the dates of the growing period have gradually prolonged, with the trend rates being -1.34 d/10a, 1.33 d/10a, 2.66 d/10a (α≥ 0.001), respectively. The spatial difference is extremely significant, which presents the following law: from the southwest to the northeast in Chinese oases, the onset date has postponed, the upset date advanced, and the growing period shortened. The mutation point of the onset and upset dates and growing period is observed in 2001, 1989, and 1996, respectively, and the upset date is more sensitive to climate warming. The cycles of the growing season of P. euphratica are 3.56-7.14 years, which is consistent with the cycle of the El Nino event, and the onset date cycles of 3.56 years and 4.28 years are consistent with that of atmospheric circulation. Cause analysis shows that the Asian polar vortex area index, the Qinghai-Tibet Plateau index, Westerly Circulation index, and the carbon dioxide emissions are the main reasons for the change of the growing season for P. euphratica, and consistent with the results of the periodic analysis. In addition, the influence of latitude in the growing season is significantly larger than that of altitude, while the onset date is more significant than the upset date in terms of latitude and altitude. Additionally, the onset and upset dates and growing period are significantly correlated with the average temperature of corresponding month, with the correlation coefficients being -0.875, 0.770, and 0.897, respectively (α≥ 0.001). Specifically, if the March average temperature increases by 1 ℃, the onset date will occur about 2.21 days earlier; if the October average temperature increases by 1 ℃, the upset date will delay for 2.76 days; if the average temperature of March to October increases by 1 ℃, the growing period will prolong for 7.78 days. This indicates that the change of P. euphratica in the growing season has a sensitive response to regional warming. This study is of great theoretical significance in understanding the response of Chinese vegetation to climate warming and ecological restoration.

Key words: P. euphratica, annual growing season, global warming, response, Chinese oases