Climate-induced treeline mortality during the termination of the Little Ice Age in the Greater Yellowstone Ecoregion, USA
Climate-induced treeline mortality during the termination of the Little Ice Age in the Greater Yellowstone Ecoregion, USA
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DOI：
10.1177/09596836211011656
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发表时间：
2021-04
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通讯作者：
Maegen L. Rochner;K. J. Heeter;G. Harley;M. Bekker;S. Horn
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作者：
Maegen L. Rochner;K. J. Heeter;G. Harley;M. Bekker;S. Horn
美国西部的古气候重建显示了中世纪气候异常（MCA，ca）内气候变化的时间，持续时间和幅度的空间变异性。900-1350 CE）和小冰河时代（LIA，CA。1350-1850 CE），表明需要更多的数据来更完整地描述该地区晚全新世气候变化。在这里，我们使用树木年代学调查如何在MCA和LIA气候变化影响的树线，白皮松（白皮松Engelm。）大黄石生态区（GYE）我们提出了两个新的千年长度的树轮年表和多行的树轮证据，从生活和残余白皮松和恩格尔曼云杉（云杉engelmannii帕里前。Engelm.）树木，包括建立和死亡的模式;树木生长的变化;霜环;和蓝色强度为基础的，重建的夏季温度，以突出LIA的终点作为GYE上个千年最冷的时期之一。树的建立和死亡率的模式表明，在MCA和气候引起的死亡率的树木在中后期LIA的后半期招聘有利的条件。这些模式对应于1800-1850 CE期间的生长减少，霜冻破坏和重建的较冷温度异常。结果提供了重要的洞察过去的气候变化如何影响重要的GYE生态系统和突出的价值，使用多条线的代理证据，沿着高空间分辨率的气候重建，以更好地描述空间和时间的变化，在MCA和LIA气候和气候变化的生态影响。
Paleoclimate reconstructions for the western US show spatial variability in the timing, duration, and magnitude of climate changes within the Medieval Climate Anomaly (MCA, ca. 900–1350 CE) and Little Ice Age (LIA, ca. 1350–1850 CE), indicating that additional data are needed to more completely characterize late-Holocene climate change in the region. Here, we use dendrochronology to investigate how climate changes during the MCA and LIA affected a treeline, whitebark pine (Pinus albicaulis Engelm.) ecosystem in the Greater Yellowstone Ecoregion (GYE). We present two new millennial-length tree-ring chronologies and multiple lines of tree-ring evidence from living and remnant whitebark pine and Engelmann spruce (Picea engelmannii Parry ex. Engelm.) trees, including patterns of establishment and mortality; changes in tree growth; frost rings; and blue-intensity-based, reconstructed summer temperatures, to highlight the terminus of the LIA as one of the coldest periods of the last millennium for the GYE. Patterns of tree establishment and mortality indicate conditions favorable to recruitment during the latter half of the MCA and climate-induced mortality of trees during the middle-to-late LIA. These patterns correspond with decreased growth, frost damage, and reconstructed cooler temperature anomalies for the 1800–1850 CE period. Results provide important insight into how past climate change affected important GYE ecosystems and highlight the value of using multiple lines of proxy evidence, along with climate reconstructions of high spatial resolution, to better describe spatial and temporal variability in MCA and LIA climate and the ecological influence of climate change.