Spatial relationship between Phytophthora ramorum and roads or streams in Oregon tanoak forests

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• 作者：Ebba Peterson ; Everett Hansen ; Alan Kanaskie
• 关键词：Forest pathology ; Invasive pathogen ; Phytophthora ramorum ; Restricted randomization ; Spatial spread ; Sudden oak death
• 刊名：Forest Ecology and Management
• 出版年：15 January, 2014
• 年：2014
• 卷：312
• 期：Complete
• 页码：216-224
• 全文大小：1321 K

文摘

The pathogen, m>Phytophthora ramorumm>, causal agent of sudden oak death (SOD) of oaks and tanoaks, continues to expand its range within Oregon despite an effort to eradicate it from native forests. With its early detection and prompt removal of infected hosts, the Oregon SOD eradication program has produced a landscape distribution of disease resulting predominantly from the long distance (100 m to 4 km) dispersal of inoculum between sites. Using a regionally restricted randomization test reflecting the south to north intensification of the SOD epidemic in Oregon, we assessed if the movement of m>P. ramorumm> between sites was spatially dependant upon roads and streams, topographic features associated with the landscape-scale movement of soil and water borne inoculum of related m>Phytophthoram> spp. Dissimilar to other forest m>Phytophthoram> spp. we found no association between SOD sites and the road network. We did, however, determine that SOD sites are occurring closer to streams than would be expected by chance, especially in regions with microclimates less conducive to establishment. Environmental conditions and/or dispersal mechanisms associated with streams may contribute to the distribution of SOD in Oregon tanoak forests. Monitoring and management should therefore concentrate on susceptible forests in close proximity to streams, especially in stands further inland from a coastal climate.