Climate change will induce a change in fire frequency in Mediterranean region and that could impact fire-adapted plant species. We showed that fire-related traits of some pine species are strongly related to other factors than fire but the recent fire history has nonetheless an impact on the variation of key traits for different fire adaptive strategies. In fire-prone Mediterranean areas, climate change is expected to exacerbate the fire pressure on ecosystems, altering the current fire regime and threatening species if they cannot acclimate. Studying intraspecific variations of some fire-related traits in relation to variation in recent fire activity is thus an important step to better understand if this acclimation is possible. We measured structural (bark thickness, shoot bulk density, self-pruning, leaf surface to volume ratio) and functional (serotiny level for Pinus halepensis only) traits in two pines species (Pinus halepensis and Pinus sylvestris) commonly found in southeastern France and that present different fire-adaptive strategies (resilience vs resistance, respectively). Populations were sampled according to different fire frequency modalities (0 vs 1 to 2 fires) along a geographical gradient, measuring numerous environmental and plant characteristics to be used cofactors in the analyses. As expected, trait variation was strongly linked to environmental and tree characteristics as well as to ontogeny overriding the effect of fire modalities, even though using integrative models with random effect. However, fire modalities had an impact on the variance of some key fire-related traits of Pinus halepensis. This study will help to anticipate the future response of these Mediterranean pine species and further underlines the importance of investigating chemical traits, flammability, and genetic variation of highly heritable traits, such as serotiny.

中文翻译：

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最近的火灾活动是否会影响黑松松的火灾相关性状。和法国地中海地区的Pinus sylvestris L.？

气候变化将导致地中海地区火灾频率的变化，这可能会影响适应火灾的植物物种。我们表明，一些松树物种的火相关性状与火以外的其他因素密切相关，但最近的火灾历史对不同火适应策略的关键性状变化有影响。在易发生火灾的地中海地区，气候变化预计会加剧生态系统的火灾压力，改变当前的火灾状况，并威胁到无法适应环境的物种。因此，研究一些与近期火灾活动变化相关的火灾相关性状的种内变化是更好地了解这种适应是否可能的重要步骤。我们测量了结构（树皮厚度、枝条体积密度、自修剪、法国东南部常见的两种松树（Pinus halepensis 和 Pinus sylvestris）的叶表面积与体积比）和功能（仅针对松树的血清素水平）特性，它们呈现出不同的火适应策略（分别是恢复力与抵抗力）。沿地理梯度根据不同的火灾频率模式（0 对 1 到 2 次火灾）对种群进行采样，测量要在分析中用作辅助因素的众多环境和植物特征。正如预期的那样，即使使用具有随机效应的综合模型，性状变异也与环境和树木特征以及超越火灾模式影响的个体发育密切相关。然而，火势对黑松一些关键火相关性状的变异有影响。