中文摘要：

通过对内蒙古锡林河流域羊草草原地区1981-1994年14年的温度观测和植被调查数据的逐年滑动平均处理．分析废地区气候和植被的相互关系以及随时间的动态变化特征。研究结果表明，内蒙古羊草草原地区的气温在研究期内具有冬、夏半年高低温变化不一致的特点：冬半年最低温度升高最为明显，最高温度升高较为明显，平均温度升高明显；夏半年最低温度升高最为明显。最高温度反而有某种程度的下降，平均温度升高不明显：全年最低温度升高最为明显，最高温度升高较为明显．平均温度升高明显。全年平均温度的升高主要是冬半年温度升高所致。羊草群落的前6种优势植物种对气温变化有不同的响应：第1、3、5优势种羊草（最优建群种）、寸草苔、变蒿的重要值和地上初级生产力随着最低温度的升高有明显的下降趋势，第2、4、6优势种大针茅（次优建群种）、西伯利亚羽茅、冰草的重要值和地上初级生产力由于种间互补作用而略有升高。这种由于竞争能力相近物种对环境变化的不同适应以及种间竞争排斥和共生互补关系．增加了植物群落种群动态变化的复杂性。因此，在研究与模拟羊草草原对温度变化响应的机理时，不仅要考虑不同温度的变化对植物的影响．还要考虑物种之间的相互作用．

英文摘要：

Since 1981, the long-term vegetation data at Leymus Chinensis grassland in Inner Mongolia has been collected. This paper analyzes the triple relations among the vegetation, temperature and time based on the smoothed data that were treated with the method of moving average. The results show that the average minimum and maximum temperatures in winter （Oct. to Mar.） in this region increased faster than that in summer （Apr. to Sep.）, and that the yearly av- erage minimum and maximum temperatures increased from 1981 to 1994 mainly because of the increasing of minimum and maximum temperatures in winter, which were in line with the trend of global wanning. In the meantime, the first 6 dominant species of this grassland responded to the temperature changes differently： the Importance Value （IV） and Aboveground Net Primary Productivity （ANPP） of the first, third and fifth dominant species, Leymus chinensis, Cares duriuscula, and A rtemisia commutate, respectively, decreased because of global warming, and the IV and ANPP of the second, fourth and sixth species, Stipa grandis, Achnatberum sibir- icum, and Agropyron michnoi, respectively, increased owing to species compensation for utiliz- ing resources. So the Stipa grandis, the second constructive species, may replace Leymus Chi- nensis, the first constructive species, and gradually become the first one if these trends continue, and the structure and function of the community would change. Therefore the interaction of competition and compensation among dominant species should also be paid attention to when we study the response of species at the Leymus Chinensis grasslan which is conducive to understanding the dynamic mechanism community d to the changes of temperatures, of individual species and entire community.