Department of Forest Resources, University of Minnesota, 1530 Cleveland Avenue North, St. Paul, MN 55108, USA.
Science. 2009 Dec 4;326(5958):1399-402. doi: 10.1126/science.1178820.
The interactive effects of rising atmospheric carbon dioxide (CO2) concentrations and elevated nitrogen (N) deposition on plant diversity are not well understood. This is of concern because both factors are important components of global environmental change and because each might suppress diversity, with their combined effects possibly additive or synergistic. In a long-term open-air experiment, grassland assemblages planted with 16 species were grown under all combinations of ambient and elevated CO2 and ambient and elevated N. Over 10 years, elevated N reduced species richness by 16% at ambient CO2 but by just 8% at elevated CO2. This resulted from multiple effects of CO2 and N on plant traits and soil resources that altered competitive interactions among species. Elevated CO2 thus ameliorated the negative effects of N enrichment on species richness.
大气中二氧化碳（CO2）浓度升高和氮（N）沉降增加对植物多样性的交互影响尚不清楚。这是值得关注的，因为这两个因素都是全球环境变化的重要组成部分，而且每个因素都可能抑制多样性，它们的综合效应可能是相加的或协同的。在一个长期的野外实验中，在大气 CO2 浓度和 N 沉降的所有组合下，种植了 16 种物种的草地组合。在 10 多年的时间里，在大气 CO2 条件下，N 的升高使物种丰富度降低了 16%，而在升高的 CO2 条件下仅降低了 8%。这是由于 CO2 和 N 对植物特性和土壤资源的多种影响，改变了物种之间的竞争相互作用。因此，升高的 CO2 缓解了 N 富集对物种丰富度的负面影响。
