呼伦贝尔草甸草原退耕后不同恢复期植物多样性变化

目的 通过揭示开垦草原退耕后不同恢复期的植物多样性变化，旨在为呼伦贝尔草甸草原管理和恢复受损草地生态系统提供理论依据。方法 文章以呼伦贝尔草甸草原为研究对象，运用样方调查和室内分析，对不同退耕年限退耕地与对照的天然草地的植被特征进行同步调查，并借助单变量一般线性模型对退耕地和天然草地的植被特征，分物种重要值，植物多样性指数及响应比等进行差异性分析，研究了开垦草原退耕后不同恢复期的植物多样性变化。结果 退耕5年、13年和17年的样地植物丰富度和植物多样性指数均显著小于对照的天然草地，而退耕19年的样地的丰富度和多样性指数与对照天然草地无显著差异；相较于退耕5年的退耕地，在退耕时间更长的退耕地中，植物群落主要层片由菊科植物转变为禾本科植物。退耕地群落演替过程中，随退耕年限增加，与天然草地间差异性减小，逐渐接近天然草地。结论 退耕是一种有效地促使植物多样性接近天然草地的措施。且除退耕年限外，退耕地与天然草地间群落相似程度同时受天然草地初始状况影响。

CHANGE OF PLANT DIVERSITY IN THE DIFFERENT RECOVERY STAGE AFTER AGRICULTURAL ABANDONMENT IN HULUNBUIR MEADOW STEPPE

This study reveals the change of plant diversity in different recovery stages after agricultural abandonment, so as to provide reference for the management and recovery of damaged grassland in Hulunbuir meadow steppe. Taking the meadow steppe in Hulunbuir as the research object, this research study the change of plant diversity in different recovery stages after agricultural abandonment, and surveyed the characteristics of plant community in abandoned land with different years of abandonment and contrast natural grassland at the same time by using the Quadra investigation and indoor analysis. And the univariate general linear model was used to analyze the difference of vegetation characteristics, species importance value, plant diversity index and response ratio between abandoned land and contrast natural grassland. The results showed that the plant richness and diversity index both showed the significantly lower value in the land abandoned for 5, 13 and 17 years compared with the contrast natural grassland, however, the abandoned land which abandoned for 19 years did not show the significant difference compared with the contrast natural grassland. The compositions of the plant community converted from Asteraceae to Gramineae in the abandoned land which had the longer time after abandonment compared with the land abandoned for 5 years. The difference about plant community between abandoned land and natural grassland was reduced with the increasing of years after abandonment. This study shows that the abandonment is an effective measure to reduce the difference of plant diversity between abandoned land and contrast natural grassland, and apart from the years after abandonment, the similarity between abandoned land and natural grassland was also affected by the initial conditions.