The impacts of nitrogen deposition on community N:P stoichiometry do not depend on phosphorus availability in a temperate meadow steppe

• Published in: Environmental pollution (1987) Vol. 242; no. Pt A; pp. 82 - 89
• Main Authors: Wang, Hong-Yi, Wang, Zheng-Wen, Ding, Rui, Hou, Shuang-Li, Yang, Guo-Jiao, Lü, Xiao-Tao, Han, Xing-Guo
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.11.2018
• Subjects: Aboveground biomass; Community composition; Ecological stoichiometry; Hulunber grassland; Intraspecific variation; Nitrogen deposition; Phosphorus addition; Plant functional traits; Hulunber grassland; Intraspecific variation; Plant functional traits; Nitrogen deposition; Ecological stoichiometry; Phosphorus addition; Aboveground biomass; Community composition
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2018.06.088

Nitrogen (N) enrichment has great consequences on several fundamental ecological processes through its impacts on plant nutrition traits (i.e. nutrient concentration and stoichiometric ratios); however, the extent to which the effects of N enrichment depend on phosphorus (P) availability are less well understood. While there is mounting evidence for the species-specific responses of plant nutrition traits to nutrient enrichment, we know little about the changes at the community-level. Here, we measured community-level biomass weighted (CWM) and non-weighted (CM) plant N and P concentrations and N:P ratio in a temperate meadow steppe after four years factorial N and P addition, with biomass and nutrition traits of each species in each plot being recorded. Nitrogen addition significantly increased community-level N concentration, decreased P concentration, and enhanced community N:P ratio. Phosphorus addition had no impacts on community-level N concentration, significantly increased P concentration, and reduced community N:P ratio. The impacts of N addition on community nutrition traits were not dependent on P addition and the community-level nutrition trait responses to N and P additions were primarily driven by intraspecific trait variation (ITV) rather than by species turnover. Community-level nutrition traits in the temperate meadow steppe were sensitive to the projected N and P enrichment. While nutrient enrichment had substantially changed community composition, its impacts on community nutrition traits were driven by ITV. Nitrogen deposition would result in imbalance of N and P in plant community, as indicated by the substantial increase in community-level N:P, which was not affected by increased P availability. [Display omitted] •Nitrogen addition results in imbalanced community N:P ratio.•The impacts of N addition on community nutrition don't depend on P availability.•Intraspecific variation drives community-level stoichiometric changes. Nitrogen-driven plant N:P imbalance has significant implications for fundamental ecological processes.