Disentangling the drivers of invasion spread in a vector-borne tree disease
Disentangling the drivers of invasion spread in a vector-borne tree disease
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DOI：
10.1111/1365-2656.12884
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发表时间：
2018-11-01
影响因子：
4.8
通讯作者：
Yamanaka, Takehiko
中科院分区：
文献类型：
--
作者：
Osada, Yutaka;Yamakita, Takehisa;Yamanaka, Takehiko
松材线虫病于20世纪初入侵日本南部，并逐渐扩展到本州北部(日本本土)。这种疾病是由一种致病的北美线虫引起的，这种线虫由当地的松材线虫传播。最近，这种疾病已经入侵了东亚和欧洲的其他地区，预计寄主松树的广泛死亡将类似于日本的历史模式。迫切需要找出PWD入侵传播的主要驱动因素，以便预测未来的传播并评估在新入侵的世界区域的遏制战略。但病原菌和病媒生物种群动态的耦合带来了相当大的复杂性，这对于理解这种和其他植物疾病的入侵很重要。在这项研究中，我们分析了历史(1980-2011年)的PWD感染和媒介丰度的记录，这些记录在空间上是广泛的，但在粗略的分类水平(无、低和高)上记录在本州北部的403个市。我们采用了一个多状态占用模型，该模型既考虑了人口统计的随机性，也考虑了分类数据中的观测误差。分析表明，即使在区域丰度保持不变的情况下，稀疏的Sawyer种群向高丰度转变的几率也低于较丰富的种群，这表明在Sawyer动力学中存在正的密度依赖，即Allee效应。气候条件(平均积温日数)在很大程度上限制了入侵在北部地区的蔓延，但这种气候对Sawyer动态的影响通常弱于Allee效应。我们的结果表明，在Sawyer动态中加强Allee效应的策略(例如，对受感染的松树进行卫生采伐)可能是减缓PWD传播的有效策略。
Pine wilt disease (PWD) invaded southern Japan in the early 1900s and has gradually expanded its range to northern Honshu (Japanese mainland). The disease is caused by a pathogenic North American nematode, which is transmitted by native pine sawyer beetles. Recently, the disease has invaded other portions of East Asia and Europe where extensive mortality of host pines is anticipated to resemble historical patterns seen in Japan. There is a critical need to identify the main drivers of PWD invasion spread so as to predict the future spread and evaluate containment strategies in newly invaded world regions. But the coupling of pathogen and vector population dynamics introduces considerable complexity that is important for understanding this and other plant disease invasions. In this study, we analysed historical (1980-2011) records of PWD infection and vector abundance, which were spatially extensive but recorded at coarse categorical levels (none, low and high) across 403 municipalities in northern Honshu. We employed a multistate occupancy model that accounted both for demographic stochasticity and observation errors in categorical data. Analysis revealed that sparse sawyer populations had lower probabilities of transition to high abundance than did more abundant populations even when regional abundance stayed the same, suggesting the existence of positive density dependence, that is an Allee effect, in sawyer dynamics. Climatic conditions (average accumulated degree days) substantially limited invasion spread in northern regions, but this climatic influence on sawyer dynamics was generally weaker than the Allee effect. Our results suggest that tactics (eg sanitation logging of infected pines) which strengthen Allee effects in sawyer dynamics may be effective strategies for slowing the spread of PWD.