title: Ecosystem carbon stocks and their changes in China's grasslands.
abstract: The knowledge of carbon (C) stock and its dynamics is crucial for understanding the role of grassland ecosystems in China's terrestrial C cycle. To date, a comprehensive assessment on C balance in China's grasslands is still lacking. By reviewing published literature, this study aims to evaluate ecosystem C stocks (both vegetation biomass and soil organic C) and their changes in China's grasslands. Our results are summarized as follows: (1) biomass C density (C stock per area) of China's grasslands differed greatly among previous studies, ranging from 215.8 to 348.1 g C m(-2) with an average of 300.2 g C m(-2). Likewise, soil C density also varied greatly between 8.5 and 15.1 kg C m(-2). In total, ecosystem C stock in China's grasslands was estimated at 29.1 Pg C. (2) Both the magnitude and direction of ecosystem C changes in China's grasslands differed greatly among previous studies. According to recent reports, neither biomass nor soil C stock in China's grasslands showed a significant change during the past 20 years, indicating that grassland ecosystems are C neutral. (3) Spatial patterns and temporal dynamics of grassland biomass were closely correlated with precipitation, while changes in soil C stocks exhibited close associations with soil moisture and soil texture. Human activities, such as livestock grazing and fencing could also affect ecosystem C dynamics in China's grasslands.
authors.affiliation: Department of Ecology, Key Laboratory for Earth Surface Processes of the Ministry of Education, College of Urban and Environmental Science, Peking University, Beijing 100871, China. jyfang@urban.pku.edu.cn
authors.forename: JingYun
authors.initials: J
authors.lastname: Fang
authors.forename: YuanHe
authors.initials: Y
authors.lastname: Yang
authors.forename: WenHong
authors.initials: W
authors.lastname: Ma
authors.forename: Anwar
authors.initials: A
authors.lastname: Mohammat
authors.forename: HaiHua
authors.initials: H
authors.lastname: Shen
mesh_terms: D018533:Biomass; D002244:Carbon; D002681:China; D017753:Ecosystem; D006109:Poaceae; D012987:Soil / Q000032:analysis
chemical_list: D012987:Soil; D002244:Carbon