Outbreaks of Douglas-Fir Beetle Follow Western Spruce Budworm Defoliation in the Southern Rocky Mountains, USA
Outbreaks of Douglas-Fir Beetle Follow Western Spruce Budworm Defoliation in the Southern Rocky Mountains, USA
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DOI：
10.3390/f13030371
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发表时间：
2022-03-01
期刊：
影响因子：
2.9
通讯作者：
Hart, Sarah J.
中科院分区：
文献类型：
--
作者：
Cole, Hailey M.;Andrus, Robert A.;Hart, Sarah J.
气候变化正在改变北美西部森林的扰动机制，导致扰动事件在时间和空间上重叠的可能性增加。虽然非生物干扰和生物干扰之间的相互作用（例如，树皮甲虫爆发对随后的野火的影响）已经被广泛研究，但多种生物干扰之间的相互作用知之甚少。落叶昆虫，如西部云杉budworm (WSB; christoneura freemanni)，已被广泛认为是树皮甲虫，如道格拉斯冷杉甲虫（DFB; Dendroctonus pseudosugae）次生定居树木的易感因素。然而，很少有定量研究支持这一观察。在这里，我们的问题是：以前的WSB损害是否增加了美国南落基山脉道格拉斯冷杉（孟氏假杉木）森林随后爆发DFB的可能性？为了量化受WSB和DFB影响的地区，我们分析了1999-2019年的航空探测调查数据。我们发现，在零模型（即随机分布）下，DFB的存在比预期的更频繁地伴随着WSB的落叶。由于气候变化预计会加剧某些生物干扰，因此了解昆虫爆发之间的相互作用对于森林管理规划以及提高我们对森林变化的了解非常重要。
Changes in climate are altering disturbance regimes in forests of western North America, leading to increases in the potential for disturbance events to overlap in time and space. Though interactions between abiotic and biotic disturbance (e.g., the effect of bark beetle outbreak on subsequent wildfire) have been widely studied, interactions between multiple biotic disturbances are poorly understood. Defoliating insects, such as the western spruce budworm (WSB; Choristoneura freemanni), have been widely suggested to predispose trees to secondary colonization by bark beetles, such as the Douglas-fir beetle (DFB; Dendroctonus pseudotsugae). However, there is little quantitative research that supports this observation. Here, we asked: Does previous WSB damage increase the likelihood of subsequent DFB outbreak in Douglas-fir (Pseudotsuga menziesii) forests of the Southern Rocky Mountains, USA? To quantify areas affected by WSB and then DFB, we analyzed Aerial Detection Survey data from 1999-2019. We found that a DFB presence followed WSB defoliation more often than expected under a null model (i.e., random distribution). With climate change expected to intensify some biotic disturbances, an understanding of the interactions between insect outbreaks is important for forest management planning, as well as for improving our understanding of forest change.