Climate and ecological disturbance analysis of Engelmann spruce and Douglas fir in the greater Yellowstone ecosystem
Climate and ecological disturbance analysis of Engelmann spruce and Douglas fir in the greater Yellowstone ecosystem
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DOI：
10.1016/j.tfp.2020.100053
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发表时间：
2021-03
期刊：
影响因子：
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通讯作者：
Brittany N. Rinaldi;R. S. Maxwell;T. Callahan;R. Brice;K. J. Heeter;G. Harley
中科院分区：
文献类型：
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作者：
Brittany N. Rinaldi;R. S. Maxwell;T. Callahan;R. Brice;K. J. Heeter;G. Harley
人为气候变化对美国大黄石生态系统（GYE）的影响非常明显，森林死亡、昆虫爆发和野火影响了森林生态系统。长期观点将有助于评估森林生态系统变异性的历史范围，更好地确定最近的森林动态和历史阈值。本研究的目的是：(1)为研究地点生长的恩格尔曼云杉和道格拉斯冷杉建立年轮年表；(2)将每个物种的年轮宽度与月度气候变量相关联；(3)检查仪器气候数据，以了解变量平均状态的变化；(4)通过量化生长释放来确定生态干扰何时发生。最后，我们讨论了气候变化和已知森林干扰背景下的气候-生长关系和生长释放。移动相关分析表明，云杉和花旗松的环宽与当年6 ~ 8月的温度和前一生长期温度呈负相关。变化分析表明，20世纪下半叶GYE最低和最高温度变化显著（p< 0.05）。干扰分析表明，两种树种对野火和虫害事件的响应都有高达25%的树木生长释放。由于气候和森林扰动错综复杂地联系在一起，因此很难理清气候变化和森林扰动对气候-生长关系的影响。我们的证据表明，月度气候变量的变化和由生长释放记录的森林扰动可以随时间影响环宽对气候的响应。树木是为整个GYE提供气候和生态健康的长期视角的关键，因为它们在年轮宽度中整合了气候和生态。
The effects of anthropogenic climate change are apparent in the Greater Yellowstone Ecosystem (GYE), USA, with forest die-off, insect outbreaks, and wildfires impacting forest ecosystems. A long-term perspective would enable assessment of the historical range of variability in forest ecosystems and better determination of recent forest dynamics and historical thresholds. The objectives of this study were to (1) develop tree-ring chronologies for Engelmann spruce and Douglas fir growing at the study location, (2) correlate the annual ring widths of each species to monthly climate variables, (3) examine the instrumental climate data for regimes shifts in the mean state of variables, and (4) determine when ecological disturbances occurred through a quantification of growth releases. Finally, we discuss both climate-growth relationships and growth releases in the context of climate regime shifts and known forest disturbances. Engelmann spruce and Douglas fir showed some similar climate responses using moving correlation analysis including negative correlations between ring width and June – August current year temperature and previous growing season temperature. Regime shift analysis indicated significant (p< 0.05) shifts in minimum and maximum GYE temperature in the latter half of the 20th century. Disturbance analysis indicated that both tree species responded to wildfire and insect outbreak events with growth releases in up to 25% of the trees. Disentangling the influence of climate regime shifts and forest disturbances on the climate-growth relationships can be difficult because climate and forest disturbances are intricately linked. Our evidence indicates that regime shifts in monthly climate variables and forest disturbances as recorded by growth releases can influence the ring width response to climate over time. Trees are key to providing a long-term perspective on climate and ecological health across the GYE because they integrate both climate and ecology in their annual ring widths.