Early 20<sup>th</sup>Century Climate-Driven Shift in the Dynamics of Forest Tent Caterpillar Outbreaks

• 作者: Barry J. Cooke Jens Roland
• 来源期刊: 美国气候变化期刊(英文)
• 学科: 医学
• 关键词: Dendroentomology Forest INSECTS OUTBREAK Cycles Synchronization Disturbance ECOLOGY CLIMATE Change
• 年，卷（期）: 2018,（2）
• 页码范围: 253-270
• 页数: 18页
• 分类号: R73

摘要

Using tree-ring analysis, we show that the dynamics of forest tent caterpillar [Malacosoma disstria (Hbn.)] outbreaks in Alberta, Canada shifted at the turn of the 20th century from cyclic, synchronous behaviour 1850-1910 to complex, asynchronous behavior 1910-1993. This shift in dynamics coincided with the emergence in 1910 of a latitudinal gradient in outbreak stability and periodicity reflecting a similar gradient in the periodicity of winter temperatures. We postulate that the synchronizing strength of winter temperatures has diminished as a result of climate warming, and that any synchronizing strength due to inter-population migration has been superseded by regionalized patterns of periodic forcing caused by weak low-frequency variability in winter temperatures. We speculate that a decrease in polar vorticity at the start of the 20th century led to increased meridional jet stream flow and more frequent arctic weather anomalies, resulting in a loss of synchronous decadal periodicity in outbreak occurrence. These changes in insect disturbance probabilities, including rising uncertainty, have profound consequences for forest disturbance risk management.