Shallow soils are warmer under trees and tall shrubs across Arctic and Boreal ecosystems
Shallow soils are warmer under trees and tall shrubs across Arctic and Boreal ecosystems
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DOI：
10.1088/1748-9326/abc994
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发表时间：
2020-11
影响因子：
6.7
通讯作者：
Heather Kropp;M. Loranty;S. Natali;A. Kholodov;A. Rocha;I. Myers-Smith;Benjamin W. Abbott;J. Abermann;E. Blanc‐Betes;D. Blok;G. Blume‐Werry;J. Boike;A. Breen;Sean M. P. Cahoon;C. Christiansen;T. Douglas;H. Epstein;G. Frost;M. Goeckede;T. Høye;S. Mamet;J. O’Donnell;D. Olefeldt;G. Phoenix;V. Salmon;A. Sannel;Sharon L. Smith;O. Sonnentag;L. Vaughn;M. Williams;B. Elberling;L. Gough;J. Hjort;P. Lafleur;E. Euskirchen;M. Heijmans;E. Humphreys;H. Iwata;B. Jones;T. Jorgenson;I. Grünberg;Yongwon Kim;J. Laundre;M. Mauritz;A. Michelsen;G. Schaepman‐Strub;K. Tape;M. Ueyama;B. Lee;K. Langley;M. Lund
中科院分区：
文献类型：
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作者：
Heather Kropp;M. Loranty;S. Natali;A. Kholodov;A. Rocha;I. Myers-Smith;Benjamin W. Abbott;J. Abermann;E. Blanc‐Betes;D. Blok;G. Blume‐Werry;J. Boike;A. Breen;Sean M. P. Cahoon;C. Christiansen;T. Douglas;H. Epstein;G. Frost;M. Goeckede;T. Høye;S. Mamet;J. O’Donnell;D. Olefeldt;G. Phoenix;V. Salmon;A. Sannel;Sharon L. Smith;O. Sonnentag;L. Vaughn;M. Williams;B. Elberling;L. Gough;J. Hjort;P. Lafleur;E. Euskirchen;M. Heijmans;E. Humphreys;H. Iwata;B. Jones;T. Jorgenson;I. Grünberg;Yongwon Kim;J. Laundre;M. Mauritz;A. Michelsen;G. Schaepman‐Strub;K. Tape;M. Ueyama;B. Lee;K. Langley;M. Lund
随着北极和北方地区气温的上升，冻土地带高大的灌木和树木的扩张，土壤正在变暖。预计植被结构和功能的变化将改变土壤的热状况，从而改变与冻土融化和碳循环有关的气候反馈。然而，目前对植被对土壤温度影响的认识仅限于局部或区域尺度，缺乏在泛北极尺度上预测土壤变暖和永久冻土稳定性所需的一般性。在这里，我们综合浅层土壤和空气温度观测广泛的空间和时间覆盖面收集在106个站点，代表九种不同的植被类型在多年冻土区。我们发现，当标准化为恒定的空气温度时，具有高大灌木和树木（>40 cm）的生态系统比具有矮苔原植被的生态系统具有更温暖的浅层土壤。在乔木和高灌木植被类型，在温暖的季节较冷的温度不会导致较冷的年平均土壤温度，这表明在寒冷的季节，而不是温暖的季节地面热制度是最关键的预测土壤变暖的生态系统下的冻土。我们的研究结果表明，高大的灌木和树木向苔原地区的扩张可以放大浅层土壤变暖，并可能增加季节性解冻深度的潜力，增加土壤碳循环速率，导致二氧化碳损失增加和永久冻土进一步解冻。
Soils are warming as air temperatures rise across the Arctic and Boreal region concurrent with the expansion of tall-statured shrubs and trees in the tundra. Changes in vegetation structure and function are expected to alter soil thermal regimes, thereby modifying climate feedbacks related to permafrost thaw and carbon cycling. However, current understanding of vegetation impacts on soil temperature is limited to local or regional scales and lacks the generality necessary to predict soil warming and permafrost stability on a pan-Arctic scale. Here we synthesize shallow soil and air temperature observations with broad spatial and temporal coverage collected across 106 sites representing nine different vegetation types in the permafrost region. We showed ecosystems with tall-statured shrubs and trees (>40 cm) have warmer shallow soils than those with short-statured tundra vegetation when normalized to a constant air temperature. In tree and tall shrub vegetation types, cooler temperatures in the warm season do not lead to cooler mean annual soil temperature indicating that ground thermal regimes in the cold-season rather than the warm-season are most critical for predicting soil warming in ecosystems underlain by permafrost. Our results suggest that the expansion of tall shrubs and trees into tundra regions can amplify shallow soil warming, and could increase the potential for increased seasonal thaw depth and increase soil carbon cycling rates and lead to increased carbon dioxide loss and further permafrost thaw.