Biodiversity Science ›› 2009, Vol. 17 ›› Issue (4): 397-405.

Special Issue: Conservation Biology: Status Quo and Challenges

• Special Issue •

### Responses of litter decomposition to biodiversity manipulation in the In-ner 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, Bei-jing 100093
• Received:2009-04-01 Revised:2009-07-10 Online:2009-07-20

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 Experi-ment (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 bi-furca were used to examine the decomposition rates of different functional group assemblages. (2) The sec-ond experiment is litter quality experiment, which included four species, Leymus chinensis, Stipa grandis, Al-lium 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 prostrata and Potentilla bifurca litter increased with the number of functional groups in the decom-posing 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 ve-getation to exploit soil resources more efficiently.

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