Negative effects of nitrogen override positive effects of phosphorus on grassland legumes worldwide-猫眼课题宝

DOI：

10.1073/pnas.2023718118

发表时间：

2021-07

期刊：

Proceedings of the National Academy of Sciences

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

P. Tognetti;S. Prober;S. Báez;E. Chaneton;J. Firn;A. Risch;M. Schuetz;Anna K. Simonsen;L. Yahdjian;E. Borer;E. Seabloom;C. Arnillas;J. Bakker;Cynthia S. Brown;M. Cadotte;M. Caldeira;P. Daleo;J. Dwyer;P. Fay;L. Gherardi;N. Hagenah;Y. Hautier;K. Komatsu;R. McCulley;J. Price;R. Standish;C. Stevens;P. D. Wragg;M. Sankaran

预测人为营养丰富对植物群落的影响对于管理对生物多样性和生态系统服务的影响至关重要。固定大气氮的植物功能类型(例如豆类)可能面临营养驱动的全球下降的特别风险，但缺乏全球规模的证据。我们在六大洲的45个草地上进行了一项试验，结果表明，随着氮素的增加，豆类的盖度、丰富度和生物量都大幅下降。虽然豆类作物受益于磷、钾和其他营养物质，但这些营养物质并没有改善氮素诱导的豆类作物的衰退。考虑到全球人为营养丰富的趋势，我们的结果表明，全球草原豆类作物的潜在数量可能会下降，这可能会对生物多样性、食物网、土壤健康以及用于食品生产的富含蛋白质的植物物种的遗传改良造成影响。人为的营养丰富正在推动全球生物多样性的下降，并改变生态系统的功能。理论表明，固定大气氮素的植物功能类型在缺氮土壤中具有竞争优势，但随着氮素供应的增加，这种优势会消失。相比之下，磷、钾和其他养分的添加可能会增强这些物种在低营养环境中的固氮能力，从而使它们受益。我们提出了一项全球范围的实验，证实了六大洲45个草原上的豆科植物固氮的这些预测。施氮降低了豆科植物的盖度、丰富度和生物量，特别是在缺氮土壤上，而不固氮植物的盖度增加。磷、钾等营养元素的添加提高了豆科牧草的丰度，但并未缓解氮素添加的负面影响。因此，增加氮素供应可能会降低世界各地草原豆类的多样性和丰度，而不考虑其他养分的可用性，从而对生物多样性、食物网、生态系统弹性和富含蛋白质的农业植物物种的遗传改良造成影响。

Significance Predicting the effects of anthropogenic nutrient enrichment on plant communities is critical for managing implications for biodiversity and ecosystem services. Plant functional types that fix atmospheric nitrogen (e.g., legumes) may be at particular risk of nutrient-driven global decline, yet global-scale evidence is lacking. Using an experiment in 45 grasslands across six continents, we showed that legume cover, richness, and biomass declined substantially with nitrogen additions. Although legumes benefited from phosphorus, potassium, and other nutrients, these nutrients did not ameliorate nitrogen-induced legume decline. Given global trends in anthropogenic nutrient enrichment, our results indicate the potential for global decline in grassland legumes, with likely consequences for biodiversity, food webs, soil health, and genetic improvement of protein-rich plant species for food production. Anthropogenic nutrient enrichment is driving global biodiversity decline and modifying ecosystem functions. Theory suggests that plant functional types that fix atmospheric nitrogen have a competitive advantage in nitrogen-poor soils, but lose this advantage with increasing nitrogen supply. By contrast, the addition of phosphorus, potassium, and other nutrients may benefit such species in low-nutrient environments by enhancing their nitrogen-fixing capacity. We present a global-scale experiment confirming these predictions for nitrogen-fixing legumes (Fabaceae) across 45 grasslands on six continents. Nitrogen addition reduced legume cover, richness, and biomass, particularly in nitrogen-poor soils, while cover of non–nitrogen-fixing plants increased. The addition of phosphorous, potassium, and other nutrients enhanced legume abundance, but did not mitigate the negative effects of nitrogen addition. Increasing nitrogen supply thus has the potential to decrease the diversity and abundance of grassland legumes worldwide regardless of the availability of other nutrients, with consequences for biodiversity, food webs, ecosystem resilience, and genetic improvement of protein-rich agricultural plant species.

Negative effects of nitrogen override positive effects of phosphorus on grassland legumes worldwide

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