Department of Ecology, Evolution, and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, Minnesota, 55108, USA.
Department of Physiological Diversity, Helmholtz Center for Environmental Research - UFZ, Permoserstrasse 15, Leipzig, 04318, Germany.
Ecology. 2021 Jun;102(6):e03355. doi: 10.1002/ecy.3355. Epub 2021 May 7.
Anthropogenic nitrogen (N) inputs are causing large changes in ecosystems worldwide. Many previous studies have examined the impact of N on terrestrial ecosystems; however, most have added N at rates that are much higher than predicted future deposition rates. Here, we present the results from a gradient of experimental N addition (0-10 g·N·m ) in a temperate grassland. After a decade of N addition, we found that all levels of N addition changed plant functional group composition, likely indicating altered function for plant communities exposed to 10 yr of N inputs. However, N addition only had weak impacts on species composition and this functional group shift was not driven by any particular species, suggesting high levels of functional redundancy among grasslands species. Adding other nutrients (P, K, and micronutrients) in combination with N caused substantially greater changes in the relative abundance of species and functional groups. Together, these results suggest that compositional change within functional groups may buffer grasslands from impacts of N deposition, but concurrent eutrophication with other elements will likely lead to substantial changes in plant composition and biomass.
人为氮（N）输入正在导致全球生态系统发生巨大变化。许多先前的研究都考察了 N 对陆地生态系统的影响；然而，大多数研究添加 N 的速率都远高于预测的未来沉积速率。在这里，我们展示了在温带草原进行的实验性 N 添加梯度（0-10 g·N·m ）的结果。在 N 添加的十年后，我们发现所有 N 添加水平都改变了植物功能群组成，这可能表明暴露于 10 年 N 输入的植物群落功能发生了改变。然而，N 添加对物种组成只有微弱的影响，这种功能群的转变不是由任何特定的物种驱动的，这表明草原物种之间存在高水平的功能冗余。与 N 一起添加其他养分（P、K 和微量元素）会导致物种和功能群的相对丰度发生更大的变化。总的来说，这些结果表明，功能群内的组成变化可能缓冲草原免受 N 沉积的影响，但与其他元素同时富营养化可能会导致植物组成和生物量的重大变化。
