Mountain pine beetle dispersal: spatiotemporal patterns and role in the spread and expansion of the present outbreak
Mountain pine beetle dispersal: spatiotemporal patterns and role in the spread and expansion of the present outbreak
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DOI：
10.1890/es10-00172.1
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发表时间：
2011-06-01
期刊：
影响因子：
2.7
通讯作者：
Walton, Adrian
中科院分区：
文献类型：
--
作者：
Chen, Huapeng;Walton, Adrian
在山松甲虫生态学中，人们对其扩散的了解最少。利用不列颠哥伦比亚省年度空中调查估算的树木死亡率，建立了一种新的区域动态概念模型，以定量确定当地（林区）和区域（省）尺度上的近距离扩散（SDD）和远距离扩散（LDD）。扩散模式的特征是基于一个汇斑到它最近的源斑之间的距离。在区域尺度上，SDD对山松甲虫向非侵染区扩散的贡献率为85.3%，对侵染区扩散的贡献率为96.8%。虽然SDD是主要的扩散方式，但LDD在本次山松甲虫爆发的早期发挥了更重要的作用。在地方尺度上，确定了三种向无虫害地区扩散的模式。首先，LDD在仅发生稀疏侵染的林区占主导地位。其次，在部分地区，LDD是虫害发生早期的主导因素或重要因素。第三，在侵染较为严重的林区，SDD在整个侵染过程中占主导地位。但大部分林区以SDD扩散方式为主。从局部和区域尺度上观察到的扩散时空格局来看，LDD是新发偏远地区侵染发生和早期的关键因素，而SDD在侵染加剧和达到流行水平时，在暴发的传播和扩大中起主导作用。但是，应当意识到，在充分考虑到局部动态之前，在分散过程中可能过分强调了LDD，这是不确定的。
Dispersal has been least understood in mountain pine beetle ecology. We developed a novel regional dynamic conceptual model of mountain pine beetle infestation using the tree mortality estimated from the British Columbia annual aerial overview survey to quantitatively determine short-distance dispersal (SDD) and long-distance dispersal (LDD) at local (forest district) and regional (provincial) scales. The dispersal patterns were characterized based on distances between a sink patch to its nearest source patch. At the regional scale, SDD accounted for 85.3% of mountain pine beetle dispersal to non-infested areas and 96.8% of beetle dispersal to infested areas. Although SDD was a dominant dispersal mode, LDD played a more important role in the early stage of the current mountain pine beetle outbreak. At the local scale, three patterns of dispersal to non-infested areas were identified. First, LDD dominated in the forest districts where only sparse infestations occurred. Second, LDD was a dominant or important factor in the early stages of the infestations in some districts. Third, SDD dominated throughout the infestations in more severely infested forest districts. However, for dispersal to infested areas, SDD was a dominant mode in most of the forest districts. We conclude from the spatiotemporal patterns of dispersal observed at local and regional scales that LDD is a key factor in the initiation and early stage of the infestations in new remote areas, and SDD dominate in the spread and expansion of the outbreak as the infestations intensify and reach epidemic levels. However, it should be conscious that there is uncertainty that LDD might have been over emphasized in the dispersal before local dynamics is fully taken into account.