放牧对短花针茅荒漠草原植物种群生态位及生态属性的影响

摘要

Niche and ecological attributes of plant population of Inner Mongolia Plateau desert steppe under free grazing (CG)were analyzed compared with enclosure (CK).The results showed that the total niche breadth of the dominant species Stipa breviflora,Cleistogenes songorica and Allium polyrhizum was significantly higher than those of other plant populations both in time and spatial scale,which were still dominant in the community.In the time scale,the degradation characteristics of grassland in enclosed area were obvious,and moderate continuous grazing can delay it in a certain way.The total niche breadth was in a rectangular relationship with the niche breadth of the enclosed area and the continuous grazing ar-ea.The niche breadth of Stipa breviflora and Cleistogenes songorica were increased by continuous graz-ing,while that of Allium polyrhizum was decreased.The ecological attributes can reflect the evolution di-rection of the plant population in community,and the ecological response rate based on the time scale can help to understand and reflect the development and demise process of the plant population in the time axis.%以内蒙古高原荒漠草原植物种群为研究对象,采用自由放牧(CG)和围封(CK)两个试验处理,对植物种群生态位及生态属性进行分析,结果表明:无论在时间还是空间尺度上,建群种短花针茅、优势种无芒隐子草、碱韭的总生态位宽度均明显高于其他植物种群,其在群落中依然占主导地位.在时间尺度上,受全球气候变化影响围封区草地的退化特征明显,采用适度自由放牧可在一定程上延缓群落退化.总生态位宽度与围封区和自由放牧区生态位宽度构成直角三角形关系.自由放牧使短花针茅和无芒隐子草生态位宽度增加,而碱韭的生态位宽度下降.生态属性可反映植物种群在群落中的演变方向,基于时间尺度探讨生态响应速率有助于理解和反映植物种群在时间轴上的发展和消亡过程.