Carbon isotopic composition of forest soil respiration in the decade following bark beetle and stem girdling disturbances in the Rocky Mountains.
Carbon isotopic composition of forest soil respiration in the decade following bark beetle and stem girdling disturbances in the Rocky Mountains.
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DOI：
10.1111/pce.12716
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
G. Maurer;A. Chan;N. Trahan;D. Moore;D. Bowling
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文献类型：
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作者：
G. Maurer;A. Chan;N. Trahan;D. Moore;D. Bowling
树皮甲虫的爆发在北美西部的森林中很普遍，降低了初级生产力和蒸腾作用，导致大面积的森林死亡，改变了生态系统的碳循环。本文对自然山松甲虫危害和人工环剥林干扰后10年的土壤呼吸碳同位素组成（δ（13）C）进行了监测。季节平均δJ沿两个时间序列沿着变化。我们发现：（a）在扰动后的前2年，近地表土壤中δJ相对于对照（<1 ‰）富集;（B）在3-7年期间亏损（1‰或无变化）;（c）在8-10年期间出现第二个富集期（1-2‰）。结果是一致的同位素模式与逐渐死亡和分解的根际生物，细根，针叶树针叶和木质根和碎片在死亡后的十年的过程中。最后，δJ在土壤中的深度比在地表附近的深度逐渐减少（13）C，而在土壤中则遵循深度富集（13）C的既定模式。总体而言，死亡率等级（<1‰）和土壤深度（<3‰）之间的δJ差异小于一个等级或一个季节内深度的变化（高达6‰）。
Bark beetle outbreaks are widespread in western North American forests, reducing primary productivity and transpiration, leading to forest mortality across large areas and altering ecosystem carbon cycling. Here the carbon isotope composition (δ(13) C) of soil respiration (δJ ) was monitored in the decade after disturbance for forests affected naturally by mountain pine beetle infestation and artificially by stem girdling. The seasonal mean δJ changed along both chronosequences. We found (a) enrichment of δJ relative to controls (<1 ‰) in near-surface soils in the first 2 years after disturbance; (b) depletion (1‰ or no change) during years 3-7; and (c) a second period of enrichment (1-2‰) in years 8-10. Results were consistent with isotopic patterns associated with the gradual death and decomposition of rhizosphere organisms, fine roots, conifer needles and woody roots and debris over the course of a decade after mortality. Finally, δJ was progressively more (13) C-depleted deeper in the soil than near the surface, while the bulk soil followed the well-established pattern of (13) C-enrichment at depth. Overall, differences in δJ between mortality classes (<1‰) and soil depths (<3‰) were smaller than variability within a class or depth over a season (up to 6‰).