Oecologia

, Volume 166, Issue 1, pp 253–264

Rapid top–down regulation of plant C:N:P stoichiometry by grasshoppers in an Inner Mongolia grassland ecosystem

Ecosystem ecology - Original Paper

Abstract

Understanding how food web interactions alter the processing of limiting nutrient elements is an important goal of ecosystem ecology. An experiment manipulating densities of the grasshopper Oedaleus asiaticus was performed to assess top–down effects of grasshoppers on C:N:P stoichiometry of plants and soil in a grassland ecosystem in Inner Mongolia (China). With increased grasshopper feeding, plant biomass declined fourfold, litter abundance increased 30%, and the plant community became dominated by non-host plant taxa. Plant stoichiometric response depended on whether or not the plant was a grasshopper host food species: C:N and C:P ratios increased with increasing grasshopper density (GD) for host plants but decreased in non-host plants. These data suggest either a direct transfer of grasshopper-recycled nutrients from host to non-host plants or a release of non-host plants from nutrient competition with heavily grazed host plants. Litterfall C:N and C:P decreased across moderate levels of grasshopper density but no effects on C:N:P stoichiometry in the surface soil were observed, possibly due to the short experimental period. Our observations of divergent C:N:P stoichiometric response among plant species highlight the important role of grasshopper herbivory in regulating plant community structure and nutrient cycling in grassland ecosystems.

Keywords

Stoichiometry Herbivory Nutrient cycling Steppe Grasshopper outbreak 

Supplementary material

442_2011_1904_MOESM1_ESM.doc (228 kb)
Supplementary material 1 (DOC 228 kb)

Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Guangming Zhang
    • 1
    • 2
  • Xingguo Han
    • 1
  • James J. Elser
    • 3
  1. 1.State Key Laboratory of Vegetation and Environmental Change, Institute of BotanyChinese Academy of SciencesBeijingChina
  2. 2.Graduate University of Chinese Academy of SciencesBeijingChina
  3. 3.School of Life SciencesArizona State UniversityTempeUSA

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