Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China.
Lhasa Plateau Ecosystem Research Station, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2019 Feb 10;650(Pt 2):2666-2673. doi: 10.1016/j.scitotenv.2018.09.384. Epub 2018 Oct 3.
A field growing/non-growing season asymmetric warming experiment (C: control, i.e., no warming in the entire year; GLNG: growing season warming lower than non-growing season warming; GHNG: growing season warming higher than non-growing season warming) was conducted in an alpine meadow of the Northern Tibetan Plateau in early June 2015. The effects of growing/non-growing season asymmetric warming on the normalized difference vegetation index (NDVI), soil adjusted vegetation index (SAVI), aboveground biomass (AGB) and gross primary production (GPP) in 2015-2017 were examined. The 'GLNG' and 'GHNG' treatments significantly increased the annual mean air temperature (T) by 2.95 °C and 2.76 °C, and the vapor pressure deficit (VPD) by 0.23 kPa and 0.28 kPa but significantly reduced the annual mean soil moisture (SM) by 0.02 m m and 0.02 m m respectively; however, changes in the annual mean T, VPD and SM were the same between the 'GLNG' and 'GHNG' treatments over the three years in 2015-2017. There were no significant differences in the SAVI and GPP among the 'C', 'GLNG' and 'GHNG' treatments over the three growing seasons in 2015-2017. The 'GLNG' and 'GHNG' treatments did not significantly affect the NDVI and AGB compared to 'C', whereas the NDVI and AGB under the 'GLNG' treatment were significantly greater than those under the 'GHNG' treatment over the three growing seasons in 2015-2017. The significant differences in NDVI and AGB between the 'GLNG' and 'GHNG' treatments may be attributed to the different effects under the 'GLNG' and 'GHNG' treatments on the non-growing season T, growing season water availability and soil nitrogen availability. Therefore, the non-growing season with a higher warming magnitude may have stronger effects on the aboveground plant production than did the growing season with a higher warming magnitude in the alpine meadow of the Northern Tibetan Plateau.
2015 年 6 月初，在青藏高原北部的高寒草甸上进行了一个生长/非生长季节非对称增温实验（C：对照，即全年无增温；GLNG：生长季增温低于非生长季；GHNG：生长季增温高于非生长季）。本研究考察了 2015-2017 年生长/非生长季节非对称增温对归一化差异植被指数（NDVI）、土壤调整植被指数（SAVI）、地上生物量（AGB）和总初级生产力（GPP）的影响。“GLNG”和“GHNG”处理分别显著提高了年平均气温（T）2.95°C 和 2.76°C，蒸气压亏缺（VPD）0.23 kPa 和 0.28 kPa，但显著降低了年平均土壤湿度（SM）0.02 m m 和 0.02 m m；然而，在 2015-2017 年的三年中，“GLNG”和“GHNG”处理之间的年平均 T、VPD 和 SM 变化没有差异。在 2015-2017 年的三个生长季节中，“C”、“GLNG”和“GHNG”处理之间的 SAVI 和 GPP 没有显著差异。与“C”相比，“GLNG”和“GHNG”处理对 NDVI 和 AGB 没有显著影响，而在 2015-2017 年的三个生长季节中，“GLNG”处理下的 NDVI 和 AGB 显著大于“GHNG”处理。“GLNG”和“GHNG”处理之间 NDVI 和 AGB 的显著差异可能归因于“GLNG”和“GHNG”处理对非生长季节 T、生长季节水分供应和土壤氮供应的不同影响。因此，在青藏高原北部高寒草甸，非生长季节增温幅度较大可能对地上植物生产力的影响大于生长季节增温幅度较大的影响。
