羊草人工草地生物多样性与生产力关系研究

1984年在内蒙古锡林郭勒盟白音锡勒牧场建立羊草人工草地,并对其进行了27年的定位观测,应用丰富度指数、Shannon-Wiener指数和Pielou均匀度指数对羊草人工草地进行多样性动态、多样性影响因素以及多样性与生产力关系的研究。结果表明:(1)播种羊草后,植物群落发生明显变化,原以冷蒿、糙隐子草和冰草为主的退化草原逐渐形成了由羊草+一二年生植物组成的草原群落。(2)1984～2010年,丰富度指数呈先缓慢升高后逐渐降低的趋势;Shannon-Wiener指数和Pielou均匀度指数都呈逐渐增加趋势,并与演替年限(t)存在指数回归关系,即Shannon-Wiener指数(DI)=0.786e0.035t(R=0.782,P<0.05)、Pielou均匀度指数(HI)=0.226e0.038t(R=0.843,P<0.05),且均达显著水平。(3)Shannon-Wiener指数与多年生禾草的生物量、密度呈显著的负相关关系,与蔷薇科和多年生杂类草的生物量、密度呈极显著的正相关关系。(4)演替前期,Shannon-Wiener指数与地上生物量呈负相关关系(r=-0.709,P<0.05);演替后期,二者呈正相关关系(r=0.867,P<0.05),即在不同的演替阶段二者表现出不同的相关关系。

Study on Relationship between Species Diversity and Productivity of Seeding Leymus chinensis Grassland

The dynamics of species diversity,factors influencing diversity,and the relationship between diversity and productivity of seeding Leymus chinensis grassland in Xilingol in Inner Mongolia were analyzed.Species diversity was quantified by species richness index,Shannon-Wiener index,and Pielou index.The results showed that:(1) seeding L.chinense in degraded grasslands dominated by Artemisia frigida,Agropyron cristatum and Cleistogenes squarrosa resulted in gradual replacement by communities composed primarily of L.chinensis,annual and biennial bunch grass.(2)During 1983~2010,species richness index first increased and then decreased,but Shannon-Wiener and Pielou indices were on the rise tendency.Species diversity indices(DI and HI) were exponentially related to the number of recovery years(t):DI=0.786e0.035t(R=0.782,P<0.05),HI=0.226e0.038t(R=0.843,P<0.05).(3)Species diversity was negatively correlated with plant density and biomass of perennial grasses,but positively correlated with density and biomass of Rosaceae and perennial forbs.(4) Correlation between diversity and biomass of L.chinensis was negative(r=-0.709,P<0.05)in the early stage of post-seeding succession,but positive at later stages(r=0.867,P<0.05),which showed a different relationship at different succession stages.