气候变化对内蒙古鄂温克旗典型草原植物物候的影响

植物物候作为气候变化敏感的指示指标,已成为全球气候变化研究的焦点。利用内蒙古典型草原区鄂温克牧业气象试验站1959—2017年的气候资料和1983—2017年的植物物候观测资料,采用趋势倾向率和逐步回归等方法,分析了鄂温克旗气候变化特征,代表性牧草大针茅和羊草返青期、开花期、黄枯期及生长季的变化趋势,并通过偏相关分析探讨了气温、降水和日照时数与牧草生育期的关系,建立了主要牧草物候期的气候模型。结果表明:(1)鄂温克旗近60年平均气温呈极显著波动增加趋势,年降水量和年日照时数的变化很小;(2)30多年来,鄂温克旗大针茅和羊草返青期总体呈推迟趋势,倾向率分别为2.2 d/10a和1.4 d/10a;开花期的变化趋势不明显;黄枯期分别以2.8 d/10a和1.5 d/10a的趋势提前;生长季长度呈明显缩短趋势;(3)3月和4月气温是影响研究区牧草返青最主要的气候因子,气温升高返青期提前;前2个月降水量对大针茅开花期的影响较大;气温升高使得黄枯期提前,而降水量增加则使得黄枯期推迟。

Effects of climate change on typical grassland plant phenology in Ewenki, Inner Mongolia

Plant phenology has become the focus of global climate change research as a sensitive indicator. Based on climate data from 1959 to 2017 and phenological observation data from 1983 to 2017 in meteorological experiment station of Ewenki, which is located in typical grassland area, the climate change characteristic and change trend of reviving, blossoming, withering, and growing season of Stipa grandis and Leymus chinensis (Trin.) Tzvel. were analyzed. The results showed that: (1) In the past 60 years, the average temperature in Ewenki has shown a very significant fluctuation and increasing trend, and the change of annual precipitation and annual sunshine hours is very small. (2) The reviving dates for Stipa grandis and Leymus chinensis (Trin.) showed a delay trend with the trend rate of 2.2 d/10a and 1.4 d/a, respectively. The blossoming stage was not change obviously. The withering dates advanced in 2.8 d/10a and 1.5 d/10a, respectively. The growing season presented tendency of shortening. (3) The temperature in March and April was the most important climate factor which affected the turning green in this study area, the rising temperature accelerated the turning green. The precipitation of two months before had great influence on blossoming dates. The rising temperature led to the advance of withering, while the increasing precipitation delayed withering dates.