Spatial variation in vegetation productivity trends, fire disturbance, and soil carbon across arctic-boreal permafrost ecosystems
Spatial variation in vegetation productivity trends, fire disturbance, and soil carbon across arctic-boreal permafrost ecosystems
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DOI：
10.1088/1748-9326/11/9/095008
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发表时间：
2016-09
影响因子：
6.7
通讯作者：
M. Loranty;W. Lieberman-Cribbin;L. Berner;S. Natali;S. Goetz;H. Alexander;A. Kholodov
中科院分区：
文献类型：
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作者：
M. Loranty;W. Lieberman-Cribbin;L. Berner;S. Natali;S. Goetz;H. Alexander;A. Kholodov
在北极苔原和北方森林生态系统中，植被结构和功能对地表能量平衡的影响可以强烈地影响冻土土壤温度。因此，植被变化可能会在冻土土壤碳动态和相关的气候反馈中发挥重要作用。导致植被变化的过程，如野火或生态系统对气温上升的反应，对于了解北极和北方生态系统对未来气候的影响至关重要。然而，这些过程在生态系统内部和生态系统之间各不相同，这种变异性在整个北极-寒带地区还没有得到系统的表征。在这里，我们量化的植被生产力的趋势，野火和近地表土壤碳，植被类型，在连续和不连续的永久冻土区的分布。西伯利亚落叶松林含有超过四分之一的连续多年冻土区的冻土土壤碳。我们观察到普遍的积极趋势，植被生产力在连续多年冻土区，而不连续多年冻土下的地区有比例较低的积极生产力的趋势和增加的地区表现出负面的生产力趋势。火灾对总面积的影响要小得多，因此对冻土土壤碳的影响也较小，绝大多数发生在落叶针叶林中。我们的研究结果表明，植被生产力的趋势可能与冻土分布，火灾影响相对较小比例的冻土土壤碳，西伯利亚落叶松林将发挥关键作用的强度的冻土碳气候反馈。
In arctic tundra and boreal forest ecosystems vegetation structural and functional influences on the surface energy balance can strongly influence permafrost soil temperatures. As such, vegetation changes will likely play an important role in permafrost soil carbon dynamics and associated climate feedbacks. Processes that lead to changes in vegetation, such as wildfire or ecosystem responses to rising temperatures, are of critical importance to understanding the impacts of arctic and boreal ecosystems on future climate. Yet these processes vary within and between ecosystems and this variability has not been systematically characterized across the arctic-boreal region. Here we quantify the distribution of vegetation productivity trends, wildfire, and near-surface soil carbon, by vegetation type, across the zones of continuous and discontinuous permafrost. Siberian larch forests contain more than one quarter of permafrost soil carbon in areas of continuous permafrost. We observe pervasive positive trends in vegetation productivity in areas of continuous permafrost, whereas areas underlain by discontinuous permafrost have proportionally less positive productivity trends and an increase in areas exhibiting negative productivity trends. Fire affects a much smaller proportion of the total area and thus a smaller amount of permafrost soil carbon, with the vast majority occurring in deciduous needleleaf forests. Our results indicate that vegetation productivity trends may be linked to permafrost distribution, fire affects a relatively small proportion of permafrost soil carbon, and Siberian larch forests will play a crucial role in the strength of the permafrost carbon climate feedback.