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Convergent responses of nitrogen and phosphorus resorption to nitrogen inputs in a semiarid grassland

Global Change Biology

By:
, , , , ,
DOI: 10.1111/gcb.12235

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Abstract

Human activities have significantly altered nitrogen (N) availability in most terrestrial ecosystems, with consequences for community composition and ecosystem functioning. Although studies of how changes in N availability affect biodiversity and community composition are relatively common, much less remains known about the effects of N inputs on the coupled biogeochemical cycling of N and phosphorus (P), and still fewer data exist regarding how increased N inputs affect the internal cycling of these two elements in plants. Nutrient resorption is an important driver of plant nutrient economies and of the quality of litter plants produce. Accordingly, resorption patterns have marked ecological implications for plant population and community fitness, as well as for ecosystem nutrient cycling. In a semiarid grassland in northern China, we studied the effects of a wide range of N inputs on foliar nutrient resorption of two dominant grasses, Leymus chinensis and Stipa grandis. After 4 years of treatments, N and P availability in soil and N and P concentrations in green and senesced grass leaves increased with increasing rates of N addition. Foliar N and P resorption significantly decreased along the N addition gradient, implying a resorption-mediated, positive plant–soil feedback induced by N inputs. Furthermore, N : P resorption ratios were negatively correlated with the rates of N addition, indicating the sensitivity of plant N and P stoichiometry to N inputs. Taken together, the results demonstrate that N additions accelerate ecosystem uptake and turnover of both N and P in the temperate steppe and that N and P cycles are coupled in dynamic ways. The convergence of N and P resorption in response to N inputs emphasizes the importance of nutrient resorption as a pathway by which plants and ecosystems adjust in the face of increasing N availability.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Convergent responses of nitrogen and phosphorus resorption to nitrogen inputs in a semiarid grassland
Series title:
Global Change Biology
DOI:
10.1111/gcb.12235
Volume
19
Issue:
9
Year Published:
2013
Language:
English
Publisher:
John Wiley & Sons
Contributing office(s):
Southwest Biological Science Center
Description:
10 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Global Change Biology
First page:
2775
Last page:
2784
Number of Pages:
10
Country:
China