不同干扰类型对呼伦贝尔草甸草原群落结构及物种多样性影响的比较

采用样方法,对比研究了2009—2011年刈割和围封干扰对呼伦贝尔草甸草原植物群落结构和物种多样性的影响. 结果表明:2009—2011年,围封干扰下建群种种群相对重要值分别为15.67%、17.73%、17.60%；而刈割干扰下建群种种群相对重要值分别为16.86%、14.84%、12.36%,呈明显下降趋势；表明围封干扰可促进建群种种群生长,而刈割则有一定的抑制作用. 2种干扰类型导致的植物群落生态类型变化趋势差异尚不显著. 2009—2011年,刈割干扰下,Margalef物种丰富度指数分别为6.05、4.58、4.27,Shannon-Wiener多样性指数分别为3.13、2.89、2.79,Pielou均匀度指数分别为0.90、0.91、0.90；围封干扰下,Margalef物种丰富度指数分别为6.46、6.03、5.32,Shannon-Wiener多样性指数分别为3.26、3.18、2.98,Pielou均匀度指数分别为0.87、0.87、0.85. 可见,在相同年份,刈割干扰下Margalef物种丰富度指数和Shannon-Wiener多样性指数均低于围封干扰,Pielou均匀度指数均高于围封干扰. 说明围封干扰有利于植物物种多样性的维持,而适度的刈割干扰则有利于植物群落的均一化. 

Comparative Study on Effects of Different Disturbances on Community Structure and Species Diversity in Hulunbuir Meadow Steppe

Effects of two disturbances (mowing and enclosure) on community structure and plant species diversity in Hulunbuir meadow steppe were studied by the controlled experiments and quadrat method. Results showed that relative importance of constructive species increased from 15.67% to 17.60% for enclosing treatment, while it decreased from 16.86% to 12.36% for mowing treatment. This indicated that enclosure promoted the growth of constructive species and mowing prohibited the growth in 3years. There was no significant difference between variation trends of plant ecotypes under the two disturbances. During the period of 2009-2011, enclosure treatment (Margalef index:6.46,6.03and 5.32; Shannon-Wiener index:3.26,3.18and 2.98; Pielou index:0.87,0.87and 0.85) showed a higher species diversity and lower evenness than that under the mowing treatment (Margalef index:6.05,4.58and 4.27; Shannon-Wiener index:3.13,2.89and 2.79; Pielou index:0.90,0.91and 0.90). This suggested that enclosure preserves species diversity and mowing could be helpful for homogenization of vegetation community.