科尔沁沙质草地物种多样性与生产力的关系

Study on the Relationship between Species Diversity and Productivity of Sandy Grassland Communities in Horqin Sandland

在地处我国北方农牧交错带的科尔沁沙地,对6个典型生境类型的沙质草地(流动沙丘、半流动沙丘、半固定沙丘、固定沙丘、干草甸和湿草甸)的17个植物群落进行取样调查,分析草地群落多样性与生产力的关系。结果表明:沙质草地的环境梯度从贫瘠到丰富的生境变化时,17个沙质草地群落类型的物种丰富度、均匀度、多样性和凋落物与生产力关系的趋势模拟均呈单峰型函数关系,说明在沙质草地中等生产力水平时,物种多样性最高、凋落物最多。科尔沁沙地由于长期的土地沙漠化,植被出现了不同程度的受损和退化,物种多样性与生产力的变化及其二者的关系,与异质性生境中生境资源限制和长期人类干扰的共同影响有关。

In this paper, the relationship between species diversity and productivity of plant communities is researched by analyzing 17 samples collected from 6 typical habitats including mobile dune, semi-mobile dune, semi-fixed dune, fixed dune, arid meadow and wet meadow. The sampling regions are situated in Naiman Deserti- fication Research Station, Inner Mongolia. The study area is a typical farming-pastoral ecotone in north China. In August 2005, the drying aboveground biomass, numbers of plant species and their diversity of 17 grassland communities in 6 plots of 1 m × 1 m were separately investigated. The study results show that there is a unimodal functional relationship between the productivity of the 17 plant communities and the 3 indexes （Shannonwienner index, Simpson index and Pielou index） in species diversity and litter with the change of environmental gradient from poor species to rich one, which reveals that the thickest in the sandy grasslands with moderate productivity species diversity is the highest and the litter is the In the study area of Horqin Sandland, the vegeta- tion is degenerated in varying degrees due to the long-time desertification. Therefore, the change of species diversity and productivity of plant communities, observed in 17 plant communities in 6 habitats, and their relationship are jointly affected by the limitation of natural resources in the heterogeneous habitats and the excessive disturbance of human activities.