Divergence of Arctic shrub growth associated with sea ice decline.
Divergence of Arctic shrub growth associated with sea ice decline.
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DOI：
10.1073/pnas.2013311117
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发表时间：
2020-12-29
影响因子：
11.1
通讯作者：
Welker JM
中科院分区：
文献类型：
--
作者：
Buchwal A;Sullivan PF;Macias-Fauria M;Post E;Myers-Smith IH;Stroeve JC;Blok D;Tape KD;Forbes BC;Ropars P;Lévesque E;Elberling B;Angers-Blondin S;Boyle JS;Boudreau S;Boulanger-Lapointe N;Gamm C;Hallinger M;Rachlewicz G;Young A;Zetterberg P;Welker JM
北极气候变化的两个显著特征是海冰的迅速减少和冻土带的“灌木化”。虽然以前的研究推断两者之间与变暖有关的联系，但这些联系仅限于少数几个地点。我们对灌木生长年表的泛北极分析揭示了两个重要的见解。苔原灌木的生长动态与整个北极的海冰减少有关;然而，虽然大多数地区的灌木增加了生长，但超过三分之一的灌木显示出生长下降的证据，以应对与海冰减少有关的变暖和干燥。这些结果突出了整个苔原生物群落的显著的生长反应异质性，这将对苔原生产力和植被气候反馈产生重要影响。北极海冰面积正在加速减少，并带来广泛的生态后果。然而，确定海冰对苔原植被的影响仍然是一个挑战。在这项研究中，我们研究了苔原灌木生长对SIE和泛北极夏季气候变化的普遍性或缺乏，利用来自19个广泛分布的站点（56°N至83°N）的23个苔原灌木年轮年表。我们表明，在灌木生长反应SIE开始在20世纪90年代中期，39%的年表显示下降和57%的径向增长（decreasers和increasers，分别）的增加有明显的分歧。结构方程模型显示，SIE下降与气温和降水量的上升有关的增加和减少与日益干燥的条件。减少往往是从北极地区夏季降水量较低，其增长下降与标准化降水蒸散指数的下降。我们的研究结果表明，水分限制，与SIE下降，可能会抑制变暖对灌木生长的积极影响，在相当一部分的陆地北极，从而复杂的植被变化和未来苔原生产力的预测。
Two defining features of climate change in the Arctic are the rapid decline of sea ice and “shrubification” of the tundra. While previous studies have inferred warming-related linkages between the two, these have been limited to a few locations. Our Pan-Arctic analysis of shrub growth chronologies reveals two important insights. Tundra shrub growth dynamics are associated with sea ice decline throughout the Arctic; however, while shrubs from most locations increased their growth, more than one-third showed evidence of declining growth in response to warming and drying associated with sea ice loss. These results highlight pronounced growth response heterogeneity across the tundra biome that will have important implications for tundra productivity and vegetation–climate feedback. Arctic sea ice extent (SIE) is declining at an accelerating rate with a wide range of ecological consequences. However, determining sea ice effects on tundra vegetation remains a challenge. In this study, we examined the universality or lack thereof in tundra shrub growth responses to changes in SIE and summer climate across the Pan-Arctic, taking advantage of 23 tundra shrub-ring chronologies from 19 widely distributed sites (56°N to 83°N). We show a clear divergence in shrub growth responses to SIE that began in the mid-1990s, with 39% of the chronologies showing declines and 57% showing increases in radial growth (decreasers and increasers, respectively). Structural equation models revealed that declining SIE was associated with rising air temperature and precipitation for increasers and with increasingly dry conditions for decreasers. Decreasers tended to be from areas of the Arctic with lower summer precipitation and their growth decline was related to decreases in the standardized precipitation evapotranspiration index. Our findings suggest that moisture limitation, associated with declining SIE, might inhibit the positive effects of warming on shrub growth over a considerable part of the terrestrial Arctic, thereby complicating predictions of vegetation change and future tundra productivity.
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影响因子：
64.8
作者：
Briffa, KR;Schweingruber, FH;Vaganov, EA
通讯作者：
Vaganov, EA
影响因子：
13.6
作者：
Fauchald P;Park T;Tømmervik H;Myneni R;Hausner VH
通讯作者：
Hausner VH
DOI：
10.1111/j.2517-6161.1995.tb02031.x
发表时间：
1995-01-01
影响因子：
5.8
作者：
BENJAMINI, Y;HOCHBERG, Y
通讯作者：
HOCHBERG, Y
影响因子：
13.6
作者：
Babst, Flurin;Bouriaud, Olivier;Frank, David C.
通讯作者：
Frank, David C.
影响因子：
3
作者：
Bunn, Andrew G.
通讯作者：
Bunn, Andrew G.