大兴安岭南段不同退化程度草甸草原植物群落结构与物种多样性

Plant community structure and species diversity in degraded meadow steppes at the southern foot of the Greater Xing'an Mountains

【目的】探究大兴安岭南段草甸草原退化过程中植物群落结构及多样性的变化规律。【方法】采用样方法对大兴安岭南段不同退化程度草甸草原植被群落结构和物种组成进行调查分析,并计算重要值和多样性指数,研究其物种多样性变化。【结果】1)研究区植物共22科52属61种,植物种类主要集中在禾本科、菊科、莎草科、蔷薇科、豆科。2)随着退化程度的加剧,植物种类,群落的生物量、高度、盖度、Shannon-Wiener指数和Simpson指数显著降低。3)狼毒(Stellera chamaejasme)在群落中的重要值逐渐增加,形成狼毒型退化草地。【结论】随着大兴安岭南段草甸草原退化程度加重,群落结构趋向单一,多样性逐渐降低,草地质量急剧下降,草地生态系统原有的稳定性被破坏。

【Objective】To clarify the changes in plant community structure and diversity during the degradation process of grassland in the southern section of the Greater Xing′an Mountains.【Method】We employed a sampling method to investigate and analyze the vegetation community structure and species composition of grasslands with varyingdegrees of degradation.Important values and diversity indices were calculated to study the changes in species diversity.【Result】A total of 22 families,52 genera,and 61 species of plants were identified in the study area,with the majority belonging to the Poaceae,Compositae,Cyperaceae,Rosaceae,and Leguminosae families.As degradation intensified,biomass,height,coverage,Shannon-Wiener index,and Simpson index of plant species and communities significantly decrease.Notablythe important value of Stellera chamaejasme increased,leading to the formation ofa S.chamaejasmedominantdegraded grassland.【Conclusion】The degradation of grassland in the southern section of the Greater Xing′an Mountains results in a simplified community structure,reduced diversity and a marked decline ingrasslandquality o,ultimately disruptingthe original stability of the grassland ecosystem.