Abstract: The relationship between productivity and biodiversity was studied under the variable precipitation treatments.Experiments were conducted in the Duolun Restoration Ecological Station of IB CAS,typical grassland of the Inner Mongolia.Three artificial precipitation grades: 50%,100% and 140% of normal rainfall were simulated,with a design of five biodiversity levels of 1,2,4,8 and 14 species in each precipitation level.The species groups were sampled by unequal probabilities,and their aboveground biomasses measured.Results showed that: Under the condition of 50% precipitation,the curve of the equation which expresses the negative relationship between productivity and biodiversity was U-shaped,but its trend is ambiguous.Productivity decreased with the increase of number of plant species,but increased when the species′number was 14.The precipitation had a significant effect on productivity regarding selected biodiversity.The curve was more obvious as precipitation was increased.Productivity increased quickly as water condition improves with 14 species group.

Key words: Biodiversity, Productivity, Steppe, Precipitation, U-shaped relationship

摘要： 为研究降水变化对草地生物多样性与生产力关系的影响,以当地自然降水量为标准,利用人工控制方法模拟50%,100%和140%3个降水梯度,并运用重要值不等概抽样,人工模拟5个生物多样性水平,以地上植物量代表生产力,探讨生物多样性与生产力在降水变化背景下的关系。结果表明:在降水减少50%的情况下,生产力与生物多样性呈接近负相关的U型关系,生产力随物种数的增加而降低;在降水不变情况下,生产力与生物多样性呈U型相关关系;生产力与生物多样性在降水量增加40%的情况下呈现更典型的U型相关关系。同时,随着降水量的增加,生物多样性与生产力格局由接近负相关的不明显的U型相关关系转变为明显的U型相关关系,水分条件的改善使生物多样性水平高的组合生产力显著提高。

关键词: 生物多样性, 生产力, 典型草原, 降水, U型相关关系