采用"空间代替时间"的方法,以不同演替系列的鼢鼠土丘植物群落为对象,通过种群生态位动态和功能群变化探讨其演替机制。选取20个主要群落组分种,采用Shannon生态位宽度和Pianka生态位重叠指数进行定量分析。结果表明:较大的生态位宽度常伴随着较大的生态位重叠,但一些具较小生态位宽度的物种之间也存在着较大的生态位重叠;物种之间的生态位重叠普遍较大。功能群变化分析表明:随着演替的进行,1、2年生杂草先迅速减小后缓慢增大,但总体减小;多年生杂草先增大后减小;多年生禾草类线性增加。反映了多年生禾草类最终在演替顶极群落中占据主导地位。采用草地质量指数分析了鼢鼠土丘植被状况,表明随着演替的进行,草地质量指数显著增加。
By using "space instead of time" approach,this paper studied the niche dynamics of plant populations and the changes of plant functional types along a successional series on zokor mounds.Twenty main plant species were chosen to analyze their niche breadth and overlap by using the Shannon and Pianka indices.The results showed that larger niche breadth was often accompanied with larger niche overlap,but some plant species with smaller niche breadth also had larger niche overlap.The niche overlap among plant species was generally large.With the succession,the annual or biennial forbs first decreased rapidly and then slowly increased but overall decreased,the perennial forbs decreased after an initial increase,while the perennial grasses increased linearly,reflecting that perennial grasses finally dominated the climax communities.The grassland quality index was used to analyze the vegetation cover on the mounds,and the results indicated that with the succession,the grassland quality index increased significantly.