高寒草甸植物群落中物种多样性与种群变异性关系及其机制初探

对高寒草甸植物群落中36个物种的物种多样性与种群变异性的关系的研究结果表明:随着物种多样性的增加,种群变异性显著降低的有4个,显著增加的有1个,其余30个物种则表现出不显著的物种多样性-种群变异性的关系;1/4的物种随着多样性的增加平均种群生物量都有下降的趋势,这提供了自然群落中密度补偿存在的实验证据,而且几乎所有物种的均值-方差尺度系数Z值为1～2.这两方面的证据都与理论预期的种群变异性随多样性增加而增加的趋势不完全一致.这可能表明:多样性与种群变异性的关系随物种而异,或者说对群落中多样性与种群变异性关系的规律性认识目前的理论还无法做到,需要寻求新的模型来解释.

The patterns and underlying mechanisms of the relationship between species diversity and population variability in alpine meadow plant communities

A study on the relationships between species diversity and population variability of 36 species from alpine meadow plant community shows that, as species diversity increases, 4 species had decreasing population variability and 1 species' population increased, while the 30 other species exhibited no significant pattern. Although the mean population biomass of about 1/4 of the species decreased with species diversity, which provides experimental evidence that density compensation exists in natural plant community, they do not show the theoretically expected tendency that population variability increases as species diversity increases. The mean-variance scaling coefficient z of almost all species varies between 1 and 2, which is also not consistent with the results theoretically expected, i.e. when Z < 2, population variability will increase as species diversity increases. Our results may suggest that the relationship between species diversity and population variability could vary with different species, or in other words, the mechanisms underlying species diversity and population variability are not yet explored by recent theories and new models need to be developed to explain them.