摘要
植被物候是植被生长发育、枯萎凋落的周期性变化现象,揭示植被物候变化及其对水热因子的响应机制具有重要的生态意义。采用两种动态阈值分别提取川西高原近20 a森林植被、草地的生长季开始期(Start of Growing Season,SOS)和生长季结束期(End of Growing Season,EOS),利用Theil-Sen Median(Sen)趋势分析、偏相关系数分析植被物候的变化特征及其对季节性气温、降水的响应。结果表明,(1)川西高原植被平均SOS以70—130 d为主,平均EOS以260—290 d为主;植被SOS整体呈提前趋势、EOS整体呈推迟趋势,SOS的平均变化速率大于EOS;植被SOS平均提前速率为2.4 d·(10 a)^(-1)(α=0.05),EOS平均推迟速率为1.4 d·(10 a)^(-1)(α=0.05);草地和森林植被SOS平均提前速率大致相同,分别为2.4 d·(10 a)^(-1)、2.3 d·(10 a)^(-1);草地EOS平均推迟速率1.4 d·(10 a)^(-1),小于森林植被2.2 d·(10 a)^(-1)。(2)温度是影响植被SOS、EOS变化的主要因素。春季温度上升导致大部分植被SOS提前,这种现象在草地和森林植被间都很常见;冬季温度上升并不能使植被SOS出现普遍提前,且由于冬季温度升高可能会影响植被的春化作用,部分植被SOS甚至与冬季温度呈正相关;秋季温度上升是植被EOS推迟的主要因素,对草地的影响尤其显著;部分植被EOS与夏季温度呈负相关,这可能与夏季温度上升产生的水分胁迫以及植被生长周期的提前结束有关。(3)冬春季降水对植被SOS的影响不明显;夏季降水减少虽然对EOS有提前效应,但秋季降水增加以及升温对植被EOS的推迟作用强于夏季降水减少所带来的影响。
Vegetation phenology means a cyclical change phenomenon including vegetation grow,wither and fall.Investigation of vegetation phenological changes and their response mechanisms to hydrothermal factors is of great ecological significance.In this paper,two dynamic thresholds were used to extract the Start of Growing Season(SOS)and End of Growing Season(EOS)of forest and grassland in the western Sichuan Plateau in the past 20 years,respectively.The variation characteristics of vegetation phenology and its responses to seasonal temperature and precipitation were analyzed by using Theil-Sen Median(Sen)trend analysis and partial correlation coefficient.The results showed that(1)the average SOS of vegetation in the western Sichuan Plateau was mainly between 70 to 130 days,and the average EOS was mainly between 260 to 290 days.The SOS was generally advanced,while the EOS was generally delayed.The average rate of change of SOS was greater than that of EOS;the average advance rate of vegetation SOS was 2.4 d·(10 a)^(-1)(α=0.05);the average delay rate of EOS was 1.4 d·(10 a)^(-1)(α=0.05).The average advance rates of SOS in grassland(2.4 d·(10 a)^(-1))and forest(2.3 d·(10 a)^(-1))were approximately the same,and the average EOS delay rate in grassland(1.4 d·(10 a)^(-1))was smaller than that of in forest(2.2 d·(10 a)^(-1)).(2)Temperature was the main factor affecting the changes of SOS and EOS.The increase of temperature in spring led to the advance of most vegetation SOS,which was common both in grassland and forest.However,the increase of temperature in winter cannot make the SOS of vegetation generally advance;because the increase in winter temperature may affect the vernalization of vegetation.The SOS of some vegetation was positively correlated with winter temperature.The rising temperature in autumn was the main factor for the delay of vegetation EOS,which was particularly significant for grassland.The EOS of some vegetation was negatively correlated with summer temperature,which may be related to the drought str
作者
孙梦鑫
张岳
辛宇
钟鼎杰
杨存建
SUN Mengxin;ZHANG Yue;XIN Yu;ZHONG Dingjie;YANG Cunjian(Key Laboratory of Land Resources Evaluation and Monitoring in Southwest/Sichuan Normal University,Chengdu 610068,P.R.China;Faculty of Geography and Resources Science,Sichuan Normal University,Chengdu 610068,P.R.China)
出处
《生态环境学报》
CSCD
北大核心
2022年第7期1326-1339,共14页
Ecology and Environmental Sciences
基金
国家重点研发计划项目(2018YFB0505303)
四川省科技厅重点研发项目(2020YFG0146)。
