188宝金博页面版

第 29卷第 10期2009年 10月生ACTA ECOLOGI CA SI N I CA态学报Vol . 29,No. 10Oct . , 2009http: / /www. ecologica. cn基金项目:国家自然科学基金资助项目 (40671028, 40371042)收稿日期: 2090204216; 　　 修订日期: 20092062293 通讯作者 Corresponding author . E2 mail: cxq@pku. edu. cn内蒙古草原羊草物候与气象因子的关系陈效逑3,李 　 倞(北京大学城市与环境学院 ,地表过程分析与模拟188宝金博页面版部重点实验室 ,北京 　100871)摘要 :研究温带草原植物物候与气象因子变化的关系 ,对于提高草原净初级生产量和碳收支估算的精度 ,掌握放牧的时宜及其区域差异 ,具有重要的科学意义和实践价值。该文利用内蒙古草原 7个牧业气象试验站 1983～2002年的羊草物候观测数据 ,对返青和黄枯日期与气温和降水量的关系进行了统计分析。结果表明 : (1)所有站点的年平均气温均呈显著升高的趋势 ,多数站点的年降水量呈不显著减少的趋势 ;同时 ,各站羊草返青期和黄枯期均以显著提前的趋势占优势 ,多数站点的生长季节 (返青到黄枯的期间 )呈缩短的趋势。 (2)在区域尺度上 ,羊草返青日期与返青前一个月均温的负相关最为显著 ,气温每升高 1℃,返青期约提前 2. 4d;在站点尺度上 ,森林草原区站点的羊草返青期早晚主要受返青前一个月均温 (负相关 )的影响 ,典型草原区站点的羊草返青期早晚主要受前一年 10月或 11月到返青期累积降水量 (负相关 )的影响 ,森林草原区最北部额尔古纳右旗的返青期早晚受返青前一个月均温和前一年 10月到返青期累积降水量的共同影响。 (3)在区域尺度上 ,羊草黄枯日期与黄枯前一个月均温的负相关最为显著 ,气温每升高 1℃,黄枯期约提前 3. 7d;在站点尺度上 ,羊草黄枯期早晚与前期气温以负相关为主 ,与前期降水量以正相关为主。关键词 :羊草 ;返青期;黄枯期 ;气象因子;内蒙古草原文章编号: 100020933(2009) 1025280211　 中图分类号:Q142,Q948, S812　 文献标识码:ARelationships between Leym us chinensis phenology and meteorological factors inInnerM ongolia grasslandsCHEN Xiao2 Qiu3,L IJingCollege of Urban and Environmental Sciences, MOE Laboratory for Earth Surface Processes, Peking University, Beijing 100871, ChinaActa Ecologica Sinica, 2009, 29(10) : 5280～5290.Abstract: Studying grassland phenology and its relation to meteorological factors is crucial for enhancing the accuracy of netprimary production and carbon sequestration estimate, and identifying appropriate grazing and harvesting times . Grasslandsof Leymus chinensis are an endemic and dominant formation in the eastern part of Eurasia. Many studies have focused onphysiological characteristics but few on phenological performances of Leymus chinensis in Inner Mongolia. Therefore, weused phenological observation data of Leymus chinensis and corresponding meteorological data from seven stations of InnerMongolia during 1983 to 2002 to reveal statistical relationships between the greenup /brownoff date of Leymus chinensis andmean air temperature/precipitation, and find out principal factors influencing greenup and brownoff dates of Leymuschinensis at regional and local scales .Annual mean air temperature showed a significant increase trend at all seven stations, whereas annual meanprecipitation indicated an insignificant decrease trend atmost of the stations . At the same time, both greenup and brownoffdates ofLeymus chinensis represented a dominantly significant advancement, and the growing season (period from greenup tobrownoff) was shortened at most of the stations . So, the response of Leymus chinensis growing season length to climatechange was different from that of woody plants, namely, a temperature increase may not induce a growing seasonlengthening ofLeymus chinensis. At regional scales, the most significantly negative correlation appeared between the Leymus