Nitrogen effects on grassland biomass production and biodiversity are stronger than those of phosphorus

Li, Weibin; Gan, Xiaoling; Jiang, Yuan; Cao, Fengfeng; Lü, Xiao-Tao; Ceulemans, Tobias; Zhao, Chuanyan

doi:10.1016/J.ENVPOL.2022.119720

Title

Nitrogen effects on grassland biomass production and biodiversity are stronger than those of phosphorus

Author

Li, Weibin

Gan, Xiaoling

Jiang, Yuan

Cao, Fengfeng

Lü, Xiao-Tao

Ceulemans, Tobias

Zhao, Chuanyan

Abstract

Human-induced nitrogen (N) and phosphorus (P) enrichment have profound effects on grassland net primary production (NPP) and species richness. However, a comprehensive understanding of the relative contribution of N vs. P addition and their interaction on grassland NPP increase and species loss remains elusive. We compiled data from 80 field manipulative studies and conducted a meta-analysis (2107 observations world-wide) to evaluate the individual and combined effects of N and P addition on grassland NPP and species richness. We found that both N addition and P addition significantly enhanced grassland above-ground NPP (ANPP; 33.2% and 14.2%, respectively), but did not affect total NPP, below-ground NPP (BNPP), and species evenness. Species richness significantly decreased with N addition (11.7%; by decreasing forbs) probably due to strong decreased soil pH, but not with P addition. The combined effects of N and P addition were generally stronger than the individual effects of N or P addition, and we found the synergistic effects on ANPP, and additive effects on total NPP, BNPP, species richness, and evenness within the combinations of N and P addition. In addition, N and P addition effects were strongly affected by moderator variables (e.g. climate and fertilization type, duration and amount of fertilizer addition). These results demonstrate a higher relative contribution of N than P addition to grassland NPP increase and species loss, although the effects varied across climate and fertilization types. The existing data also reveals that more long-term (≥5 years) experimental studies that combine N and P and test multifactor effects in different climate zones (particularly in boreal grasslands) are needed to provide a more solid basis for forecasting grassland community response and C sequestration response to nutrient enrichment at the global scale.

Language

English

Source (journal)

Environmental pollution. - London, 1987, currens

Publication

London : 2022

ISSN

0269-7491 [print]

1873-6424 [online]

DOI

10.1016/J.ENVPOL.2022.119720

Volume/pages