title: Effects of P addition on plant C:N:P stoichiometry in an N-limited temperate wetland of Northeast China.
abstract: Phosphorus (P) enrichment induced by anthropogenic activities results in modified plant nutrient status, which potentially alters the stoichiometry of carbon (C), nitrogen (N), and P in plants. However, how increased P availability changes plant C:N:P stoichiometry at different hierarchical scales is unclear in N-limited ecosystems. In this study, we conducted a four-level P addition experiment (0, 1.2, 4.8, and 9.6gPm(-)(2)year(-1)) to elucidate the effect of P enrichment on plant C:N:P stoichiometric ratios at both the species and community levels in a freshwater wetland in the Sanjiang Plain, Northeast China. We found that species- and community-level plant C:N:P stoichiometry responded consistently to six years of P addition, although there was a shift in species dominance. Phosphorus addition increased plant N and P concentrations and thus decreased C:N, C:P, and N:P ratios irrespective of the P addition levels. These similar change trends at different scales resulted from the identical responses of plant N and P concentrations in different species to P addition. Moreover, plant N concentration exhibited an increasing trend with increasing P addition levels, whereas plant C:N ratio showed a declining trend. At the community level, P addition at the rates of 1.2, 4.8, and 9.6gPm(-2)year(-1) decreased the C:N ratio by 24%, 27%, and 34%; decreased the C:P ratio by 33%, 35%, and 38%; and decreased the N:P ratio by 12%, 10%, and 6%, respectively. Our results indicate that the stoichiometric responses to P addition are scale-independent, and suggest that altered plant C:N:P stoichiometry induced by P enrichment would stimulate organic matter decomposition and accelerate nutrient cycles in N-limited temperate freshwater wetlands.
authors.affiliation: Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; The Three Gorges Institute of Ecological Environment, Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China. Electronic address: maorong@cigit.ac.cn.
authors.forename: Rong
authors.initials: R
authors.lastname: Mao
authors.affiliation: Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Hui-Min
authors.initials: HM
authors.lastname: Chen
authors.affiliation: Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
authors.forename: Xin-Hou
authors.initials: XH
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
authors.forename: Fu-Xi
authors.initials: FX
authors.lastname: Shi
authors.affiliation: Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China. Electronic address: songcc@neigae.ac.cn.
authors.forename: Chang-Chun
authors.initials: CC
authors.lastname: Song
keywords: C:N:P stoichiometric ratios; Deyeuxia angustifolia; Eutrophication; Freshwater marsh; Glyceria spiculosa; Species dominance