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| Review on litter decomposition in forest ecosystems |
| Xu Xiaojing,Zhang Kai,Liu Bo,Lan Changchun,Xu Xiaoniu |
| College of Forestry and Landscape Architecture,Anhui Agricultural University,230036,Hefei,China |
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Abstract Litter decomposition and related nutrient release are fundamental process of nutrient cycling in forest ecosystems,and an important component of global carbon budget.A thorough understanding of decomposition process is essential in understanding the structure and functioning of forest ecosystems.Decomposition predictors can be divided into three types,including environmental index(e.g.actual evapotranspiration(AET)),litter physical and chemical quality indices(e.g.leaf tensile strength(LTS),C/N,lignin/N and C/P ratios etc.).The mechanism of nutrient release in decomposition is extremely complicated.There are three types of dynamical patterns of nutrients during the decomposition process such as leaching-release,leaching-accumulation-release,and accumulation-release,which vary with litter types,decomposition phases,and elements with respect to both the mobility of nutrients and limitations of nutrients on decomposer organisms.The decomposition of mixed-species litter exhibits different responses such as synergistic,antagonistic or null response,depending largely on species composition and the proportion of individual litter types.Mixtures of different litters likely result in both chemical diversity and microhabitat complexity,which correlated with the change in abundance and physiological activities of the decomposers.Emerging researches suggested that in the mixed-litter experiment,the representation of litter types in proportions should determined by those in the natural setting.Elevated CO2 can affect the litter chemistry and biotic and abiotic environment including soil resource availability,soil fauna community and the activity of soil enzymes responsible for the decomposition of litter.However,elevated CO2 do not alter the relationship between litter chemistry and decomposition.The results from most emerging researches implied that changes in the species composition of the plant community under elevated CO2 have a much larger effect on the long-term rate of nutrient cycling than changes in atmospheric CO2 alone.
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Received: 20 November 2006
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