Using -24‰ and -14‰ as the endpoints of stable carbon isotopic composition of total organic carbon (δ 13CTOC) of surface soil under pure C3 and C4 vegetation, and surface soil δ 13CTOC data from eastern China, Aus...Using -24‰ and -14‰ as the endpoints of stable carbon isotopic composition of total organic carbon (δ 13CTOC) of surface soil under pure C3 and C4 vegetation, and surface soil δ 13CTOC data from eastern China, Australia and the Great Plains of North America, we estimate the relative abundance of C3/C4 plants (i.e., the ratio of C3 or C4 biomass to local primary production) in modern vegetation for each region. The relative abundance of modern C3/C4 vegetation from each region is compared to the corresponding climatic parameters (mean annual temperature and precipitation) to explore the relationship between relative C4 abundance and climate. The results indicate that temperature controls the growth of C4 plants. However, even where temperature is high enough for the growth of C4 plants, they will only dominate the landscape when precipitation declines as temperatures increase. Our results are consistent with those of other investigations of the geographic distribution of modern C4 plant species. Therefore, our results provide an important reference for interpretation of past C3/C4 relative abundance records in these three regions.展开更多
基金supported by the Key Project of Chinese Ministry of Education (109151)the National Natural Science Foundation of China (40672121 and 40872111)the NSFC National Innovative Research Team Project (40721061)
文摘Using -24‰ and -14‰ as the endpoints of stable carbon isotopic composition of total organic carbon (δ 13CTOC) of surface soil under pure C3 and C4 vegetation, and surface soil δ 13CTOC data from eastern China, Australia and the Great Plains of North America, we estimate the relative abundance of C3/C4 plants (i.e., the ratio of C3 or C4 biomass to local primary production) in modern vegetation for each region. The relative abundance of modern C3/C4 vegetation from each region is compared to the corresponding climatic parameters (mean annual temperature and precipitation) to explore the relationship between relative C4 abundance and climate. The results indicate that temperature controls the growth of C4 plants. However, even where temperature is high enough for the growth of C4 plants, they will only dominate the landscape when precipitation declines as temperatures increase. Our results are consistent with those of other investigations of the geographic distribution of modern C4 plant species. Therefore, our results provide an important reference for interpretation of past C3/C4 relative abundance records in these three regions.
