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The relative contributions of intra- and inter-specific variation in driving community stoichiometric responses to nitrogen deposition and mowing in a grassland

Hou, Shuang-Li, Lü, Xiao-Tao, Yin, Jiang-Xia, Yang, Jun-Jie, Hu, Yan-Yu, Wei, Hai-Wei, Zhang, Zhi-Wei, Yang, Guo-Jiao, Liu, Zhuo-Yi, Han, Xing-Guo
The Science of the total environment 2019 v.666 pp. 887-893
arid lands, biogeochemical cycles, grasslands, mowing, nitrogen, nitrogen content, phosphorus
The stoichiometric characteristics of plant communities are important controller for several fundamental ecological processes. The effects of environmental changes on community stoichiometric characteristics are driven by intra- and inter-specific variation. However, the relative importance of both pathways has seldom been empirically examined.We quantified the relative contribution of intra- and inter-specific variation to the changes of community nitrogen (N) and phosphorus (P) concentrations after seven-year factorial N addition and mowing treatments in a semi-arid grassland of northern China.Nitrogen addition significantly increased community N and P concentrations and N:P ratio. Mowing significantly increased community N concentration and N:P. Intra-specific variation contributed more than inter-specific variation to the total variability of all the nutritional and stoichiometric characteristics, with intra-specific variation accounting for 68%, 70%, and 75% of the total variation in community-level N, P, and N:P, respectively. Negative covariations between the contribution of intra- and inter-specific variation occurred for community N and P concentrations. Further, N addition and mowing interacted to affect the impacts of intra- and inter-specific variation on community N concentration and N:P stoichiometry.Our results highlight different ways of trait selection for N addition and mowing treatments. Interactions between those two factors make it more difficult to accurately predict the responses of plant-mediated biogeochemical cycles under co-occurrence of environmental changes.