青藏高原草地物候动态及其对驱动因子的响应  

Grassland phenological dynamics and its response to driving factors on the Qinghai-Tibet Plateau

作　　者：吉珍霞 裴婷婷[1,2] 陈英 侯青青[3] 谢保鹏 吴华武 JI Zhenxia;PEI Tingting;CHEN Ying;HOU Qingqing;XIE Baopeng;WU Huawu(College of Resources and Environment,Gansu Agricultural University,Lanzhou 730070,Gansu,China;College of Management,Gansu Agricultural University,Lanzhou 730070,Gansu,China;College of Pratacultural Science,Gansu Agricultural University,Lanzhou 730070,Gansu,China;Key Laboratory of Grassland Ecosystem,Ministry of Education/Gansu Agricultural University,Lanzhou 730070,Gansu,China;Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,Jiangsu,China)

机构地区：[1]甘肃农业大学资源与环境学院,甘肃兰州730070 [2]甘肃农业大学管理学院,甘肃兰州730070 [3]甘肃农业大学草业学院,甘肃兰州730070 [4]草业生态系统教育部重点实验室/甘肃农业大学,甘肃兰州730070 [5]中国科学院南京地理与湖泊研究所,江苏南京210008

出　　处：《草业科学》2023年第1期4-14,共11页Pratacultural Science

基　　金：甘肃省青年科技基金项目(21JR7RA853);甘肃农业大学青年导师扶持基金项目(GAU-QDFC-2021-06);甘肃农业大学公招博士科研启动项目(2017RCZX-35)。

摘　　要：植被物候动态是多重因子影响的结果,尤其在对外界扰动响应敏感的青藏高原草地生态系统。本研究利用2000-2020年MODIS 16 d合成的归一化植被指数(normalization difference vegetation index, NDVI)数据,选用动态阈值法提取了青藏高原逐年的植被物候期,探究了青藏高原草地物候动态变化及其对驱动因子的响应。结果表明:1) 2000-2020年青藏高原草地生长季始期(start of the growing season, SOS)从西北向东南呈提前趋势,每年提前约0.19 d;草地生长季末期(end of the growing season, EOS)整体呈推迟趋势,每年推迟约0.19 d;草地生长季长度(length of the growing season, LOS)由西北向东南逐渐增长。2)风速和连续5 d最大降雨(yearly maximum five-day precipitation, RX5day)是影响草地LOS的主要因素,且因子间两两交互作用要强于单个因子对植被物候的影响,尤其表现在RX5day与温度和风速与温度之间的交互。3)草地LOS与风速和RX5day的回归系数有明显的空间异质性。藏北高原草地LOS随风速增大而变长,随RX5day增大而变短。青海高原和藏南谷地的草地LOS随风速增大而变短。川藏高山峡谷区草地LOS随RX5day增大而变长。综上,本研究可为研究区内生态系统保护和畜牧业的发展提供一定科学依据。The phenological dynamics of vegetation are the result of multiple factors, especially in the alpine grassland ecosystem of the Qinghai-Tibet Plateau(QTP), which is sensitive to external disturbances. In this study, we used the Normalization Difference Vegetation Index(NDVI) data generated by MODIS from^(2)000 to 2020 and the dynamic threshold method to extract the vegetation phenology in the QTP, and explored the dynamic change of grassland phenology and its response to driving factors. The results showed that: 1) From^(2)000 to 2020, the start of the growing season on the QTP showed an earlier trend from northwest to southeast, with an annual advance of 0.19 d, and the overall trend was delayed by the same amount at the end of the growing season. The length of the grassland growing season increased gradually from northwest to southeast. 2) Wind speed and yearly maximum five-day precipitation(RX5day) were the main factors influencing the grassland length of the growing season(LOS), and the pairwise interaction between the factors was stronger than the influence of a single factor on vegetation phenology. RX5day and wind speed both interacted with temperature.3) The regression coefficients of grassland LOS with wind speed and Rx5day showed obvious spatial heterogeneity. The grassland LOS in the northern Tibetan Plateau increased with wind speed and decreased with RX5day, while that in the Qinghai Plateau and South Tibet Valley became shorter with the increase of wind speed. The grassland LOS increased with the increase of RX5day in the Sichuan-Tibet alpine valley area. This study provides a scientific basis for ecosystem protection and the development of animal husbandry in the study area.

关 键 词：草地物候 地理探测器 地理加权回归模型 动态阈值法 风速 RX5day 青藏高原 

分 类 号：S812[农业科学—草业科学]