Relationships between Soil Carbon Distribution and Species Diversity and Community Biomass at Different Alpine Meadows

WANG Changting1,2,LONG Ruijun3,LIU Wei2,WANG Qilan2,ZHANG Li2,4,WU Pengfei1 (1. College of Life Science and Technology,Southwest University for Nationalities,Chengdu 610041,China; 2. Northwest Institute of Plateau Biology,Chinese Academy of Sciences,Xining 810001,China; 3. College of Pastoral Agriculture Science and Technology,Lanzhou University,Lanzhou 730070,China; 4. Graduate University of Chinese Academy of Sciences,Beijing 100049,China)  

Soil organic carbon is a critical component in the terrestrial carbon reservoir,and its storage,distribution,and conversion play a major role in the globe carbon budget. Better understanding the distribution pattern of soil carbon storage in different alpine meadows will facilitate the projection of global change on the terrestrial carbon cycling. The relationship between biodiversity and ecosystem functioning has aroused considerable interest and controversy in recent ecological literature. Heterotrophic microbial communities inhabiting soil dictate key processes that control the ecosystem carbon and nitrogen cycling,and they potentially represent a mechanistic link between plant diversity and ecosystem functions. Measurements of different plant community types and soils were used at the Haibei alpine meadow ecosystem station during the period 2003-2005. This study was conducted to examine characteristics of soil microbial biomass carbon (MBC),soil organic carbon (SOC),and their relationships with productivity and diversity at different alpine meadows. Results indicated that the plant diversity index (H') decreased with soil total organic carbon and soil microbial biomass carbon increasing. Community biomass increased with soil total organic carbon and MBC increasing in different alpine meadow communities. The MBC and organic total carbon at 0-10 cm,10~20 cm,20~40 cm,and 0~40 cm soil layer in Kobresia tibetica swamp meadow were found to be 2.99,1.78,0.38,and 1.72 g/kg dry soil,and 183.31,78.92,20.58,and 94.27 g/kg dry soil,respectively,which were significantly higher than other types of meadows (p0.01). The SOC and MBC contents decreased with increasing soil depth,exhibiting differences at the same soil depth in different type communities. There existed a significant correlation of the two indices with soil organic and soil total N,indicating that both SOC and MBC could be used as the important indicators to measure changes in soil quality. The soil resources showed a stronger positive correlation with aboveground biomass of different grassland type communities. Changes in microbial composition and community biomass largely resulted from a higher level of plant production,rather than from plant diversity. It was found that the plant species differed in their biochemical composition. Changes in plant diversity could substantially change the production,thereby controlling the composition and function of heterotrophic microbial communities. The amounts of living plant biomass in alpine meadow communities affected soil microbial biomass carbon,soil organic carbon,and soil fertility. These results suggest that the original soil conditions,plant community composition,and community productivity play an eminent role in regulating plant community productivity and microbial biomass and activity in different alpine meadows.

【Fund】： 国家自然科学基金重点项目(编号:30730069);; 西南民族大学高层次人才引进项目资助
【CateGory Index】： S154

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