退化草原轻耙处理过程中植物种多样性变化的研究

Changes of Species Diversity on Degenerated Steppe after Light Harrow

利用多年样方资料的统计分析,对退化草原群落轻耙处理后恢复过程中的生物多样性变化规律及引起这些变化的主要植物种群进行研究,结果表明:在退化群落耙地恢复过程中,整个群落的物种丰富度变化不大,物种分布的均匀性指数随演替过程呈现波动下降的趋势,多样性指数也呈现波动下降的趋势,恢复后期有所升高,且物种分布的均匀性是造成物种多样性指数变化的主要原因。羊草(Leymuschinensis)的密度和生物量的变化与多样性指数具有极显著的负相关关系。冷蒿(Aartemisiafrigida)、洽草(Koeleriacristata)的密度和生物量与多样性指数具有极显著的正相关关系。隐子草(Cleistogenessquarrosa)、变蒿(A.commutata)的密度与多样性指数具有极显著的正相关关系。多样性指数与耙地处理后的恢复年限(11a间)的关系可表示为: 以密度为指标的多样性指数Dn=3.579-0.665Lnx (r=-0.9185); 以生物量为指标的多样性指数Dw=4.4-0.7696Lnx (r=0.8667)。

The quadrat data from 1983 to 1994 were used to statistically analyze the changes in diversity and the main plant populations on degenerated steppe after light harrow for restoration. The species richness hasnt obvious change. The evenness and diversity indexes decreased along with the restoration succession of community and the main reason affecting diversity index was species evenness. The diversity index negatively correlated with the density and biomass of Leymus chinense; while positively correlated with the density and biomass of Artemisia frigida, Koeleria cristata; and also positively correlated with the density of A. commutata, Cleistogenes squarrosa. The relationship between diversity index and restoration years (x) could be expressed as the regressive equation: ①Index of density, Dn=3.579-0.665Lnx (r=-0.9185); ②Index of biomass, Dw=4.4-0.7696Lnx (r=0.8667).