Biomass carbon stocks and their changes in northern China's grasslands during 1982-2006
Biomass carbon stocks and their changes in northern China's grasslands during 1982-2006
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DOI：
10.1007/s11427-010-4020-6
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发表时间：
2010-07-01
影响因子：
9.1
通讯作者：
Mohammat, Anwar
中科院分区：
文献类型：
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作者：
Ma WenHong;Fang JingYun;Mohammat, Anwar
草地面积约占中国总面积的三分之一，在全球陆地碳循环中发挥着重要作用。然而，鲜为人知的是，在这些草原的生物量碳储量和动态。在2001-2005年期间，我们连续进行了五次野外采样，调查了北方草地的地上和地下生物量。利用1982-2006年341个采样点的测量数据和归一化植被指数（NDVI）时间序列数据，研究了过去25年来生物量碳储量的变化。结果表明，中国北方草地生物量碳储量为557.5Tg C（1 Tg=10（12）g），地上生物量平均密度为39.5gCm（-2），地下生物量平均密度为244.6gCm（-2）。在过去的25年中，观察到0.2 Tg C yr（-1）的增长率，但草地生物量自20世纪80年代末以来没有经历过显着的变化。季节性降雨（1 - 7月）是草地生物量碳储量变化的主导因子，但不同草地类型的草地生物量对气候变化的响应不同。干旱草原的生物量（即，荒漠草原和典型草原）与降水量显著相关，而湿润草原（即，高寒草甸）与1 - 7月平均气温呈正相关。这些结果表明，中国不同草地生态系统对未来气候变化可能表现出不同的响应。
Grassland covers approximately one-third of the area of China and plays an important role in the global terrestrial carbon (C) cycle. However, little is known about biomass C stocks and dynamics in these grasslands. During 2001-2005, we conducted five consecutive field sampling campaigns to investigate above-and below-ground biomass for northern China's grasslands. Using measurements obtained from 341 sampling sites, together with a NDVI (normalized difference vegetation index) time series dataset over 1982-2006, we examined changes in biomass C stock during the past 25 years. Our results showed that biomass C stock in northern China's grasslands was estimated at 557.5 Tg C (1 Tg=10(12) g), with a mean density of 39.5 g C m(-2) for above-ground biomass and 244.6 g C m(-2) for below-ground biomass. An increasing rate of 0.2 Tg C yr(-1) has been observed over the past 25 years, but grassland biomass has not experienced a significant change since the late 1980s. Seasonal rainfall (January-July) was the dominant factor driving temporal dynamics in biomass C stock; however, the responses of grassland biomass to climate variables differed among various grassland types. Biomass in arid grasslands (i.e., desert steppe and typical steppe) was significantly associated with precipitation, while biomass in humid grasslands (i.e., alpine meadow) was positively correlated with mean January-July temperatures. These results suggest that different grassland ecosystems in China may show diverse responses to future climate changes.