Martin Calvo Maria, Prentice Iain Colin
Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, UK.
AXA Chair of Biosphere and Climate Impacts, Grand Challenges in Ecosystems and the Environment and Grantham Institute - Climate Change and the Environment, Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot, SL5 7PY, UK.
New Phytol. 2015 Nov;208(3):987-94. doi: 10.1111/nph.13485. Epub 2015 May 29.
Dynamic global vegetation models (DGVMs) can disentangle causes and effects in the control of vegetation and fire. We used a DGVM to analyse climate, CO2 and fire influences on biome distribution and net primary production (NPP) in last glacial maximum (LGM) and pre-industrial (PI) times. The Land surface Processes and eXchanges (LPX) DGVM was run in a factorial design with fire 'off' or 'on', CO2 at LGM (185 ppm) or PI (280 ppm) concentrations, and LGM (modelled) or recent climates. Results were analysed by Stein-Alpert decomposition to separate primary effects from synergies. Fire removal causes forests to expand and global NPP to increase slightly. Low CO2 greatly reduces forest area (dramatically in a PI climate; realistically under an LGM climate) and global NPP. NPP under an LGM climate was reduced by a quarter as a result of low CO2 . The reduction in global NPP was smaller at low temperatures, but greater in the presence of fire. Global NPP is controlled by climate and CO2 directly through photosynthesis, but also through biome distribution, which is strongly influenced by fire. Future vegetation simulations will need to consider the coupled responses of vegetation and fire to CO2 and climate.
动态全球植被模型（DGVMs）能够厘清植被与火灾控制中的因果关系。我们使用一个DGVM来分析末次盛冰期（LGM）和工业化前（PI）时期气候、二氧化碳和火灾对生物群落分布及净初级生产力（NPP）的影响。陆地表面过程与交换（LPX）DGVM采用析因设计运行，设置火灾“关闭”或“开启”、LGM（185 ppm）或PI（280 ppm）浓度的二氧化碳以及LGM（模拟）或现代气候条件。通过斯坦 - 阿尔珀特分解分析结果，以区分主要影响和协同作用。去除火灾会使森林扩张，全球NPP略有增加。低二氧化碳浓度会大幅减少森林面积（在PI气候下显著减少；在LGM气候下符合实际情况）以及全球NPP。由于低二氧化碳浓度，LGM气候下的NPP降低了四分之一。在低温条件下，全球NPP的降低幅度较小，但在有火灾的情况下降幅更大。全球NPP直接通过光合作用受气候和二氧化碳控制，也通过生物群落分布受其控制，而生物群落分布受火灾影响很大。未来的植被模拟需要考虑植被和火灾对二氧化碳及气候的耦合响应。
