Department of Plant Pathology, University of California, One Shields Ave, Davis, CA, 95616, USA.
New Phytol. 2012 Dec;196(4):1145-1154. doi: 10.1111/j.1469-8137.2012.04352.x. Epub 2012 Oct 9.
The first wildfires in sudden oak death-impacted forests occurred in 2008 in the Big Sur region of California, creating the rare opportunity to study the interaction between an invasive forest pathogen and a historically recurring disturbance. To determine whether and how the sudden oak death pathogen, Phytophthora ramorum, survived the wildfires, we completed intensive vegetation-based surveys in forest plots that were known to be infested before the wildfires. We then used 24 plot-based variables as predictors of P. ramorum recovery following the wildfires. The likelihood of recovering P. ramorum from burned plots was lower than in unburned plots both 1 and 2 yr following the fires. Post-fire recovery of P. ramorum in burned plots was positively correlated with the number of pre-fire symptomatic California bay laurel (Umbellularia californica), the key sporulating host for this pathogen, and negatively correlated with post-fire bay laurel mortality levels. Patchy burn patterns that left green, P. ramorum-infected bay laurel amidst the charred landscape may have allowed these trees to serve as inoculum reservoirs that could lead to the infection of newly sprouting vegetation, further highlighting the importance of bay laurel in the sudden oak death disease cycle.
首次在突发橡树死亡影响的森林中发生野火是在 2008 年加利福尼亚州的大苏尔地区，这为研究入侵性森林病原体和历史上反复发生的干扰之间的相互作用创造了难得的机会。为了确定侵入性森林病原体拟盘多毛孢菌是否以及如何在野火中存活下来，我们在已知在野火前受感染的森林样地中完成了密集的基于植被的调查。然后，我们使用 24 个基于样地的变量作为野火后拟盘多毛孢菌恢复的预测因子。与未燃烧的样地相比，在火灾后 1 年和 2 年内，从燃烧的样地中恢复拟盘多毛孢菌的可能性较低。在燃烧的样地中，拟盘多毛孢菌的灾后恢复与加州月桂（Umbellularia californica）的数量呈正相关，加州月桂是该病原体的关键产孢宿主，与火灾后月桂死亡率呈负相关。留下绿色、感染拟盘多毛孢菌的加州月桂的斑驳燃烧模式可能使这些树木成为接种体库，从而导致新发芽植被的感染，进一步强调了月桂在突发橡树死亡疾病循环中的重要性。
