中文摘要：

分析了近50年来中国主要草原区以温度和降水变化为主的气候变化特征，阐述了气温和降水的改变对中国主要草原生态系统影响的相关研究结果，总结了气候变化对中国主要草原区植被时空格局的影响。近50年来，中国草原区气温普遍升高，降水变化时空差异较大。多数研究结果表明，温度升高对植物物候的影响存在较大的不确定性，对草原植被净初级生产力（net primary productivity，NPP）的影响也具有区域性差异，增温加速土壤碳分解，降低植物物种多样性。降水增多使植物物候期提前，生长季延长，草原NPP提高，物种丰富度增加，但植被生长对降水的变化具有一定的滞后性；不同的水热组合对植被生长的影响不同。温度升高和降水增多均会使草原植被覆盖度增加。总的来说，气候变化对中国草原区植被生长起促进作用，但在局部区域，抑制其生长。建议在未来的气候变化条件下，结合宏观和微观方面，系统分析中国草地生态系统的敏感性和脆弱性，加强对中国草地生态系统的综合研究，从而降低研究结果的不确定性。

英文摘要：

This paper analyzed the characteristics of climate changes in major grassland areas of China during recent 50 years. It also elaborated the research findings about the effect of temperature and precipitation changes on main grassland ecological system in China. The paper summarized the effect of climate changes on the vegetation spatial and temporal pattern of major grassland areas in china. In the past 50 years, the temperature of grassland areas in China was generally rising, while the changes of precipitation had larger time and space differences. The majority research results indicated that the effect of temperature rise on plant phenology had a great uncertainty, and its effect on the net primary productivity （NPP） of grassland vegetation had regional differences. Temperature rise would accelerate the decomposition of carbon in soil, and reduce the plant species diversity. Meanwhile, precipitation increase would make the plant phenology period in advance, prolong its growing season, raise grassland NPP, and improve species richness. But the vegetation growth had a certain hysteresis to the variation of precipitation. Different combination of temperature and precipitation had different influences on the vegetation growth. Temperature rise and precipitation increase could increase grassland vegetation coverage. Generally speaking, climate change could promote the growth of vegetation in glassland areas in China. But in certain region, it might suppress vegetation growth. The paper suggestedunder future climate change condition to combine the macro and micro aspects, to systematically analyze the sensitivity and vulnerability of grassland ecosystem in China, and to strengthen the comprehensive study on grassland ecosystem, so as to reduce the uncertainty of research results.