Age matters: Older Alnus viridis ssp. fruticosa are more sensitive to summer temperatures in the Alaskan Arctic
Age matters: Older Alnus viridis ssp. fruticosa are more sensitive to summer temperatures in the Alaskan Arctic
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年龄很重要：较老的 Alnus viridis ssp。
DOI：
10.1111/1365-2435.14307
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发表时间：
2023
影响因子：
5.2
通讯作者：
Heslop, Calvin
中科院分区：
文献类型：
--
作者：
Drew, Jackson W.;Bret‐Harte, Marion S.;Buchwal, Agata;Heslop, Calvin
北极正在迅速变暖，冻土带植被群落组成在某些地方正从矮小、匍匐的灌木转变为高大、直立的灌木。在北极的大部分地区，以生长环宽度衡量的灌木次生生长对气候的敏感性随着变暖的加剧而发生了变化，但人们并不完全了解灌木年龄如何导致气候敏感性的变化。我们研究了西伯利亚桤木，Alnus viridissp .fruticosa，这是一种大型固氮灌木，在过去的50年里，它对气候变暖做出了响应，向北扩展了范围。我们对26株灌木和94个横截面进行了连续切片，得出了98年的年轮年代学，其中包括阿拉斯加北部一株142年的西伯利亚桤木。我们测试了在过去一个世纪（1920-2017年），次生生长对气候的敏感性是如何变化的，以及灌木年龄如何影响桤木生长的气候敏感性。研究发现，随着时间的推移，桤木生长对7月平均气温更加敏感。老灌木对6月和7月温度的敏感性高于年轻桤木。然而，在任何灌木生长的前30年，个体之间的温度敏感性没有差异。此外，各截面生长序列对6月温度的敏感性与灌木的年龄有关。我们的研究结果表明，随着时间的推移，年龄对气候敏感性有贡献，可能是通过改变大小和减少桤木对固氮的依赖来改变灌木内部碳收支。年龄更大、更敏感的桤木可能增强C和N循环，同时具有更大的招募潜力。将年龄与气候敏感性、土壤补充和总氮投入联系起来，将使我们能够更好地预测北极变暖的生态系统碳和氮循环。在《华尔街日报》博客上阅读免费的《简明语言摘要》。
The Arctic is rapidly warming, and tundra vegetation community composition is changing from small, prostrate shrubs to taller, erect shrubs in some locations. Across much of the Arctic, the sensitivity of shrub secondary growth, as measured by growth ring width, to climate has changed with increased warming, but it is not fully understood how shrub age contributes to shifts in climate sensitivity.We studied Siberian alder,Alnus viridisssp.fruticosa, a large nitrogen‐fixing shrub that has responded to climate warming with northward range expansion over the last 50 years. We used serial sectioning of 26 individual shrubs and 94 cross‐sections to generate a 98‐year growth ring chronology, including one 142‐year‐old, Siberian alder in Northern Alaska. We tested how secondary growth sensitivity to climate has changed over the past century (1920–2017) and how shrub age affects climate sensitivity of alder growth through time.We found that over time, alder growth as expressed by the stand chronology became more sensitive to July mean monthly air temperature. Older shrubs displayed higher sensitivity to June and July temperature than younger alders. However, during the first 30 years of growth of any shrub, temperature sensitivity did not differ among individuals. In addition, the June temperature sensitivity of growth series from individual cross‐sections depended on the age of the attached shrub.Our results suggest that age contributes to climate sensitivity, likely through modifying internal shrub carbon budgets by changing size and reducing alder's dependence on N‐fixation over time. Older, more sensitive alder may enhance C and N‐cycling while having greater recruitment potential. Linking alder age to climate sensitivity, recruitment and total N‐inputs will enable us to better predict ecosystem carbon and nitrogen cycling in a warmer Arctic.Read the free Plain Language Summary for this article on the Journal blog.