Plant Communities Soil Carbon and Soil Nitrogen

Authors: WenJin Li JinHua Li Johannes M H Knops Gang Wang JuJie Jia YanYan Qin

Publish Date: 2009/08/25

Volume: 44, Issue: 4, Pages: 755-765

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Abstract

To assess the recovery trajectory and selfmaintenance of restored ecosystems a successional gradient 1 3 5 15 and 30 years after abandonment was established in a subalpine meadow of the eastern Tibetan Plateau in China Plant communities and soil carbon and nitrogen properties were investigated and analyzed Regression analyses were used to assess the models linear or quadratic relating measures of species richness soil carbon and nitrogen properties to fallow time We found that species richness S increased over the first 20 years but decreased thereafter and aboveground biomass showed a linear increase along the fallow time gradient The richness of different functional groups forb grass and legume changed little along the fallow time gradient but their corresponding above ground biomass showed the Ushaped humped or linear pattern Soil microbial carbon MBC and nitrogen MBN in the upper 20 cm showed a Ushaped pattern along the fallow time gradient However soil organic carbon Corg and total nitrogen TN in the soil at depth greater than 20 cm showed significant patterns of linear decline along the fallow time gradient The threshold models of species richness reflected best the recovery over the 15 year fallow period These results indicated that fallow time had a greater influence on development of the plant community than soil processes in abandoned fields in subalpine meadow ecosystem These results also suggested that although the succession process did not significantly increase soil C an increase in microbial biomass at the latter stage of succession could promote the decomposability of plant litter Therefore abandoned fields in subalpine meadow ecosystem may have a high resilience and strong rehabilitating capability under natural recovery conditionThis research was supported by a grant No 30871823 from the Natural Science Foundation of China and the Research Station of Alpine Meadow and Wetland Ecosystems of Lanzhou University We are very grateful to professor Guozhen Du Shiting Zhang and Xianhui Zhou for helping in field investigation and two anonymous reviewers for the constructive suggestions on our manuscript

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