Abstract: Grazing is one of the main utilizations of grassland. Plant functional traits as measures of adaptability of plants to grazing, which play an important role in the adaptation of grassland plants to grazing. In order to study the grazing avoidance strategies of plant functional traits under different grazing intensities and further clarify the importance of rational grazing, the functional traits of two dominant species (Stipa breviflora and Cleistogenes songorica) in desert steppe under different grazing intensities were investigated on the data collected from the long-term grazing platform of 15 years, and the correlation between these traits was also explored in the study. The results showed that:Leaf length and plant height of S. breviflora decreased significantly with the increase of grazing intensities (P<0.05). The cluster diameter of C. songorica under light grazing were significantly higher than those under no grazing, moderate and heavy grazing due to the compensatory growth of plants. However, the moderate and heavy grazing resulted in a significant decrease in plant traits (P<0.05). Aboveground biomass of both S. breviflora and C. songorica was significantly positively correlated with its plant height, cluster diameter and stem leaf dry weight (P<0.01). Therefore, the two dominant species in the desert steppe have different feedback mechanisms to grazing, which provide an important scientific basis for further researches on the desert steppe.

Key words: Functional traits, Stipa breviflora, Cleistogenes songorica, Grazing intensity

摘要： 放牧是草地最主要的利用方式之一，植物功能性状能够客观的表达植物应对放牧的适应性，为了研究植物功能性状在不同放牧强度下的避牧策略和进一步阐明合理放牧的重要性，本研究依托15年的长期放牧平台，探讨在不同放牧强度下荒漠草原两大优势物种短花针茅（Stipa breviflora）和无芒隐子草（Cleistogenes songorica）的15个功能性状变化以及其之间联系。结果表明：短花针茅的叶长和株高随放牧强度的增大而显著降低（P<0.05）；由于植物的补偿性生长轻度放牧增加了无芒隐子草的株高和株丛径，但是中度和重度放牧对无芒隐子草功能性状均产生了消极的作用（P<0.05）；短花针茅和无芒隐子草的地上生物量与株高、丛幅径以及茎叶干重均呈极显著正相关关系（P<0.01）。由此可见，荒漠草原两种优势种对放牧干扰有着不同的响应机制，这为深入了解荒漠草原提供了重要的科学依据。

关键词: 功能性状, 短花针茅, 无芒隐子草, 放牧强度