Department of Ecology, Evolution, and Behavior, University of Minnesota, 1479 Gortner Avenue, St. Paul, Minnesota, 55108, USA.
The Nature Conservancy, 1101 West River Parkway, Minneapolis, Minnesota, 55415, USA.
Ecol Appl. 2021 Sep;31(6):e02363. doi: 10.1002/eap.2363. Epub 2021 Jun 10.
Diversity and nitrogen addition have positive relationships with plant productivity, yet climate-induced changes in water availability threaten to upend these established relationships. Using long-term data from three experiments in a mesic grassland (ranging from 17 to 34 yr of data), we tested how the effects of species richness and nitrogen addition on community-level plant productivity changed as a function of annual fluctuations in water availability using growing season precipitation and the Standardized Precipitation-Evapotranspiration Index (SPEI). While results varied across experiments, our findings demonstrate that water availability can magnify the positive effects of both biodiversity and nitrogen addition on productivity. These results suggest that productivity responses to anthropogenic species diversity loss and increasing nitrogen deposition could depend on precipitation regimes, highlighting the importance of testing interactions between multiple global change drivers.
多样性和氮添加与植物生产力呈正相关，但气候引起的水分可利用性变化可能会打破这些既定关系。本研究使用中湿润草地的三个实验中的长期数据（数据时间跨度为 17 至 34 年），通过生长季降水和标准化降水蒸散指数（SPEI），检验了物种丰富度和氮添加对群落水平植物生产力的影响如何随水分可利用性的年际波动而变化。尽管实验结果存在差异，但我们的研究结果表明，水分可利用性可以放大生物多样性和氮添加对生产力的积极影响。这些结果表明，对人为引起的物种多样性丧失和增加的氮沉降的生产力响应可能取决于降水模式，突出了测试多个全球变化驱动因素之间相互作用的重要性。
