Range shifts in a foundation sedge potentially induce large Arctic ecosystem carbon losses and gains
Range shifts in a foundation sedge potentially induce large Arctic ecosystem carbon losses and gains
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DOI：
10.1088/1748-9326/ac6005
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发表时间：
2022-03
影响因子：
6.7
通讯作者：
S. Curasi;N. Fetcher;R. Hewitt;P. Lafleur;M. Loranty;M. Mack;J. May;I. Myers-Smith;S. Natali;S. Oberbauer;Thomas C. Parker;O. Sonnentag;Sergio A Vargas Zesati;S. Wullschleger;A. Rocha
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作者：
S. Curasi;N. Fetcher;R. Hewitt;P. Lafleur;M. Loranty;M. Mack;J. May;I. Myers-Smith;S. Natali;S. Oberbauer;Thomas C. Parker;O. Sonnentag;Sergio A Vargas Zesati;S. Wullschleger;A. Rocha
基础物种对生态系统结构和功能的影响不成比例地大。因此，它们分布的未来变化可能是气候变暖世界中生态系统碳(C)循环的重要决定因素。我们使用野外数据、机器学习生态位模型和陆地生物圈模型(TBM)评估了基础绒毛莎草作为气候脆弱的C种群所起的作用。现场数据显示，在过去的38年里，阿拉斯加北坡从1981年到2019年的象牙密度每平方米减少了∼0.97只象牙。这一下降趋势令人担忧，因为草袜是一种巨大的北极碳储量，它使我们研究区域的土壤有机层碳储量平均增加6.9%，相当于745 Tg C。到2100年，我们预计，在目前袜子丰富的地区(例如，北坡的−为每平方米0.8ttc，−为85tgC)，袜子密度的变化可能会使tussock C的库存减少41%，而在目前tussock稀缺的地区(例如，维多利亚岛的每平方米+0.9tsock和+81tgC)，tussock C的库存可能增加46%。这些气候诱导的草袜C储量变化与一组TBM预测的植被C储量变化相似，但有时在符号上相反。我们的结果说明了短袜作为决定未来北极碳储量的基础物种的重要作用，并强调了在TBM中更好地代表这一物种的必要性。
Foundation species have disproportionately large impacts on ecosystem structure and function. As a result, future changes to their distribution may be important determinants of ecosystem carbon (C) cycling in a warmer world. We assessed the role of a foundation tussock sedge (Eriophorum vaginatum) as a climatically vulnerable C stock using field data, a machine learning ecological niche model, and an ensemble of terrestrial biosphere models (TBMs). Field data indicated that tussock density has decreased by ∼0.97 tussocks per m2 over the past ∼38 years on Alaska’s North Slope from ∼1981 to 2019. This declining trend is concerning because tussocks are a large Arctic C stock, which enhances soil organic layer C stocks by 6.9% on average and represents 745 Tg C across our study area. By 2100, we project that changes in tussock density may decrease the tussock C stock by 41% in regions where tussocks are currently abundant (e.g. −0.8 tussocks per m2 and −85 Tg C on the North Slope) and may increase the tussock C stock by 46% in regions where tussocks are currently scarce (e.g. +0.9 tussocks per m2 and +81 Tg C on Victoria Island). These climate-induced changes to the tussock C stock were comparable to, but sometimes opposite in sign, to vegetation C stock changes predicted by an ensemble of TBMs. Our results illustrate the important role of tussocks as a foundation species in determining future Arctic C stocks and highlight the need for better representation of this species in TBMs.