施肥和刈割对亚高山草甸物种多样性与生产力及其关系的影响

施肥和刈割分别对植物群落物种多样性和生产力有重要的影响。采用不同施肥水平和刈割频度, 研究了施肥和刈割对亚高山草甸植物群落物种多样性与生产力及其关系的影响。结果显示, 5年的施肥和刈割处理对群落地上生物量均有显著影响, 但对物种多样性影响不显著; 物种多样性与生产力之间的关系因施肥和刈割次数的不同而不同, 有负相关、二次函数关系和不相关等几种类型, 多数为不相关。此结果表明施肥和刈割并不总是一致性地影响群落物种多样性与生产力。因此, 不同施肥和刈割处理下的亚高山草甸植物群落生产力与物种多样性之间并没有确定的关系。

Effects of fertilization and clipping on species diversity,productivity and their relationship in subalpine meadow

Aims The objective of this study was to determine whether fertilization and clipping would affect species diversity, productivity, and the relationship between species diversity and productivity in a subalpine meadow of China.Methods The experiment was set up as a randomized block design consisting of three levels of fertilization and three intensities of clipping with eight replications, using quadrat size of 0.5 × 0.5 m². The aboveground biomass and species diversity were measured within each quadrat. The relationship between species diversity and productivity were tested by plotting aboveground biomass against species diversity based on linear and non-linear regressions by treatments. Important findings Fertilization and clipping had significant effects on aboveground biomass; community biomass increased with the level of fertilization but decreased with the clipping intensity. Both fertilization and clipping had no apparent effects on species diversity. The relationships between aboveground biomass and species diversity occurred as monotonic, quadratic, or non-correlated depending on fertilization and clipping treatments, meaning that the relationship between species diversity and productivity is not always isotropic and changes with conditions of fertility and level of biomass removal in the community. Thus, productivity is unlikely related to species diversity under conditions of varying fertilization regimes and clipping treatments.