Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, Blindern, Oslo, Norway.
Biol Rev Camb Philos Soc. 2012 Feb;87(1):34-51. doi: 10.1111/j.1469-185X.2011.00183.x. Epub 2011 May 11.
In recent decades we have seen rapid and co-occurring changes in landscape structure, species distributions and even climate as consequences of human activity. Such changes affect the dynamics of the interaction between major forest pest species, such as bark beetles (Coleoptera: Curculionidae, Scolytinae), and their host trees. Normally breeding mostly in broken or severely stressed spruce; at high population densities some bark beetle species can colonise and kill healthy trees on scales ranging from single trees in a stand to multi-annual landscape-wide outbreaks. In Eurasia, the largest outbreaks are caused by the spruce bark beetle, Ips typographus (Linnaeus), which is common and shares a wide distribution with its main host, Norway spruce (Picea abies Karst.). A large literature is now available, from which this review aims to synthesize research relevant for the population dynamics of I. typographus and co-occurring species under changing conditions. We find that spruce bark beetle population dynamics tend to be metastable, but that mixed-species and age-heterogeneous forests with good site-matching tend to be less susceptible to large-scale outbreaks. While large accumulations of logs should be removed and/or debarked before the next swarming period, intensive removal of all coarse dead wood may be counterproductive, as it reduces the diversity of predators that in some areas may play a role in keeping I. typographus populations below the outbreak threshold, and sanitary logging frequently causes edge effects and root damage, reducing the resistance of remaining trees. It is very hard to predict the outcome of interspecific interactions due to invading beetle species or I. typographus establishing outside its current range, as they can be of varying sign and strength and may fluctuate depending on environmental factors and population phase. Most research indicates that beetle outbreaks will increase in frequency and magnitude as temperature, wind speed and precipitation variability increases, and that mitigating forestry practices should be adopted as soon as possible considering the time lags involved.
近几十年来，由于人类活动的影响，我们看到了景观结构、物种分布甚至气候的快速协同变化。这些变化影响了主要森林害虫（如鞘翅目：象甲科，小蠹科）与其宿主树木之间相互作用的动态。通常，这些甲虫在破碎或严重受损的云杉中繁殖；在高密度的情况下，一些甲虫物种可以在从单个树木到多年度的景观范围的暴发等规模上，入侵和杀死健康的树木。在欧亚大陆，最大的暴发是由云杉小蠹虫，Ips typographus（Linnaeus）引起的，它很常见，与主要宿主挪威云杉（Picea abies Karst.）共享广泛的分布。现在有大量的文献，本综述旨在从中综合与变化条件下 I. typographus 及其伴生种的种群动态相关的研究。我们发现，云杉小蠹虫的种群动态往往是亚稳的，但具有良好的地点匹配的混合物种和年龄异质林则不太容易发生大规模的暴发。虽然应该在下次繁殖期之前清除和/或去皮大量的原木，但密集地清除所有粗死木可能会适得其反，因为它会减少在某些地区可能在将 I. typographus 种群控制在暴发阈值以下发挥作用的捕食者的多样性，而且卫生采伐经常会引起边缘效应和根部损伤，降低剩余树木的抵抗力。由于入侵甲虫物种或 I. typographus 在其当前范围之外建立，种间相互作用的结果非常难以预测，因为它们的性质和强度可能会有所不同，并且可能会根据环境因素和种群阶段而波动。大多数研究表明，随着温度、风速和降水变异性的增加，甲虫暴发的频率和规模将会增加，并且考虑到涉及的时间滞后，应该尽快采取减轻林业的做法。
