呼伦贝尔草原不同草地利用方式下生物多样性与生物量的关系

生物多样性与生产力的关系是当前生态学中研究的重点之一,以呼伦贝尔草原为研究对象,通过连续两个生长季的野外监测,从草地植物功能型的角度探讨了在不同利用方式下草地物种丰富度与地上生物量的关系,结果表明：（1）不同草地利用方式显著影响草地生物多样性和生产力,在3种不同利用方式中,生物多样性总体的趋势是割草〉围封〉放牧,其中Shannon-Wiener指数、Simpson指数和物种丰富度均差异显著;割草草地地上生物量最高,围封草地次之,放牧草地最少。（2）将草地植物按照植物功能型分类,放牧草地1、2年生植物占优势,随着物种丰富度的增加,1、2年生植物生物量没有明显的变化趋势;割草草地以禾本科植物和非禾本科植物为主,随着物种丰富度的增加,禾本科植物生物量呈下降趋势,而非禾本科植物变化不明显;围封草地中禾本科植物占优势,其他功能型植物分布较均匀,多度、频度和生物量等差异不显著。（3）3种草地利用方式中只有围封草地物种丰富度和地上生物量存在显著的正相关,即随着物种丰富度的增加,生物量也随之升高。其他两种利用方式下,物种丰富度对地上生物量没有显著影响。

Relationships between biodiversity and biomass under different regimes of grassland use in Hulunbeir, Inner Mongolia

Relationship between biodiversity and productivity has become a central issue in ecological research because the world is facing the problems of biodiversity losing and ecosystem degradation. However, the relationship between biodiversity and productivity and the underlying mechanism are not clear yet especially when we consider the environmental and anthropogenic impacts. To discuss the relationship between biodiversity and productivity in different intensities and types of anthropogenic activity, a study of two peak growing seasons in the Hulunbeir grassland was carried out. The relationships between species richness and above-ground biomass according to six plant functional groups in three different grassland-use types were discussed. Results indicated that: (1) Grassland biodiversity and productivity varied significantly with different grassland-use types. Biodiversity had the decreasing trend from grassland mowing (Mw) to explosure (Ex) and grazing (Gz). The Shannon-wiener index, Simpson index and species richness were all significantly different among the three grassland-use types. The Mw had the highest, the Ex had the medium, and the Gz had the lowest above-ground biomass. (2) Grassland plants were classified into six plant functional groups. The annuals and biennials (AB) were the dominant functional group in Gz and the above-ground biomass of AB had no obvious relationship with species richness; perennial rhizome (PR) grass, perennial bunchgrass (PB) and perennial forbs (PF) played important roles in Mw. The above-ground biomass of PR grass and PB reduced with the increase of species richness while the above-ground biomass of PF did not varied with species richness; PR grass and PB were the dominant plant functional groups in Ex. The rest functional groups (LG, SS, AB, PF) had a weak spatial heterogeneity with the similar levels of frequency, abundance and biomass. (3) There was a positive linear relationship between species richness and above-ground biomass in Ex. No significant relationships between species richness and above-ground biomass were found in Gz or Mw.