Biodiv Sci ›› 2009, Vol. 17 ›› Issue (4): 397-405.  DOI: 10.3724/SP.J.1003.2009.09082

Special Issue: 保护生物学: 现状和挑战 生物多样性与生态系统功能

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Responses of litter decomposition to biodiversity manipulation in the Inner Mongolia grassland of China

Xiaofang Sun1,2, Jianhui Huang1, Meng Wang1,2, Xingguo Han1,*()   

  1. 1 State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093
    2 Graduate University of the Chinese Academy of Sciences, Beijing 100049
  • Received:2009-04-01 Accepted:2009-07-10 Online:2009-07-20 Published:2009-07-20
  • Contact: Xingguo Han


Litter decomposition as one of the important ecosystem functions has strong interactions with ecosystem biodiversity. This is because recycling of nutrients during litter decomposition has major control over the carbon cycle and nutrient availability. Therefore, decomposition is crucial to qualify diversity effects on ecosystem processes. Here, we conducted a litterbag experiment in temperate grassland of Inner Mongolia, China, to examine the effects of altering plant functional group diversity on litter decomposition. We performed three related decomposition experiments within the Inner Mongolia Grassland Removal Experiment (IMGRE), which was established with a manipulated gradient of functional group diversity. (1) The first experiment is a microenvironment experiment, in which litters of Kochia prostrata and Potentilla bifurca were used to examine the decomposition rates of different functional group assemblages. (2) The second experiment is litter quality experiment, which included four species,Leymus chinensis, Stipa grandis, Allium tenuissimum,and Chenopodium aristatum. Different litter combinations of the four species were placed in a homogeneous environment to test the effects of litter composition on the decomposition. (3) The third experiment was a combination of the above two experiments. The single or a combination of plant litter from species rich plots was placed back to its original plots. Our results showed that decomposition rates of both Kochia prostrataand Potentilla bifurca litter increased with the number of functional groups in the decomposing environment in the first experiment. Non-additive patterns of mass loss were observed in the second experiment. A significant negative correlation between carbon content of the litter mixtures and litter mass loss rate, and positive correlations between nitrogen, phosphorus concentrations and litter mass loss rates were observed. When decomposition microenvironment and litter composition were assessed simutanously, no significant correlations were observed between decomposition rates and the number of functional groups or species diversity. However, a positive correlation was found between nitrogen loss and functional groups. Thus, we concluded that litter diversity itself had smaller effects than species identity, and decomposition was less sensitive to changes in plant diversity compared with other ecosystem processes which depend more on vitality of plants. Furthermore, our results have the implication that higher plant species richness allows vegetation to exploit soil resources more efficiently.

Key words: litter decomposition, functional group diversity, decomposition microenvironment, litter mixture, non-additive effects