Potential shifts in the aboveground biomass and physiognomy of a seasonally dry tropical forest in a changing climate
Potential shifts in the aboveground biomass and physiognomy of a seasonally dry tropical forest in a changing climate
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DOI：
10.1088/1748-9326/ab7394
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发表时间：
2020-03-01
影响因子：
6.7
通讯作者：
Andrade, Eunice M.
中科院分区：
文献类型：
--
作者：
Castanho, Andrea D. A.;Coe, Michael T.;Andrade, Eunice M.
季节性干旱热带森林 (SDTF) 占全球净初级生产力 (NPP) 年际变化的三分之一。因此，干燥热带森林结构的大规模变化可能会以当前预测中未充分考虑的方式显着影响全球二氧化碳通量。这项研究量化了气候变化如何重塑世界上最大的 SDTF 之一——巴西东北部的卡廷加地区。我们将不同代表性浓度路径（RCP）下的历史数据和未来气候预测与空间明确的地上生物量估计结合起来，以建立气候和植被分布之间的关系。我们发现卡廷加的地貌、地上生物量和气候密切相关，而且该地区的生物气候包络线正在迅速变化。与 1950 年至 1979 年的参考期相比，2008 年至 2017 年，该地区 90% 以上的地区已转向干燥气候空间。全球气候模型集合（基于 IPCC AR5）表明，到 21 世纪末，最干燥的卡廷加地貌（荆棘林地到非植被地区）可能会从该地区的 55% 扩大到 78% (RCP 2.6) 或多达 87% (RCP8.5)。这些变化将相当于到本世纪末平衡地上生物量减少 30%-50%（分别为 RCP 2.6 和 RCP8.5）。我们的结果与其他 SDTF 报告的历史植被变化一致。卡廷加的预计变化将对该地区的生物量和生物多样性产生大规模影响，凸显了 SDTF 对于全球碳预算的重要性。了解本研究中提出的此类变化将有助于区域规划，并有助于减轻其负面社会影响。
Seasonally dry tropical forests (SDTFs) account for one-third of the interannual variability of global net primary productive (NPP). Large-scale shifts in dry tropical forest structure may thus significantly affect global CO2 fluxes in ways that are not fully accounted for in current projections. This study quantifies how changing climate might reshape one of the largest SDTFs in the world, the Caatinga region of northeast Brazil. We combine historical data and future climate projections under different representative concentration pathways (RCPs), together with spatially explicit aboveground biomass estimates to establish relationships between climate and vegetation distribution. We find that physiognomies, aboveground biomass, and climate are closely related in the Caatinga-and that the region's bioclimatic envelope is shifting rapidly. From 2008-2017, more than 90% of the region has shifted to a dryer climate space compared to the reference period 1950-1979. An ensemble of global climate models (based on IPCC AR5) indicates that by the end of the 21st century the driest Caatinga physiognomies (thorn woodlands to non-vegetated areas) could expand from 55% to 78% (RCP 2.6) or as much as 87% (RCP8.5) of the region. Those changes would correspond to a decrease of 30%-50% of the equilibrium aboveground biomass by the end of the century (RCP 2.6 and RCP8.5, respectively). Our results are consistent with historic vegetation shifts reported for other SDTFs. Projected changes for the Caatinga would have large-scale impacts on the region's biomass and biodiversity, underscoring the importance of SDTFs for the global carbon budget. Understanding such changes as presented in this study will be useful for regional planning and could help mitigate their negative social impacts.