Fire is a major disturbance linked to the evolutionary history and climate of Mediterranean ecosystems, where the vegetation has evolved fire‐adaptive traits (e.g., serotiny in pines). In Mediterranean forests, mutualistic feedbacks between trees and ectomycorrhizal (ECM) fungi, essential for ecosystem dynamics, might be shaped by recurrent fires. We tested how the structure and function of ECM fungal communities of Pinus pinaster and Pinus halepensis vary among populations subjected to high and low fire recurrence in Mediterranean ecosystems, and analysed the relative contribution of environmental (climate, soil properties) and tree‐mediated (serotiny) factors. For both pines, local and regional ECM fungal diversity were lower in areas of high than low fire recurrence, although certain fungal species were favoured in the former. A general decline of ECM root‐tip enzymatic activity for P. pinaster was associated with high fire recurrence, but not for P. halepensis . Fire recurrence and fire‐related factors such as climate, soil properties or tree phenotype explained these results. In addition to the main influence of climate, the tree fire‐adaptive trait serotiny recovered a great portion of the variation in structure and function of ECM fungal communities associated with fire recurrence. Edaphic conditions (especially pH, tightly linked to bedrock type) were an important driver shaping ECM fungal communities, but mainly at the local scale and probably independently of the fire recurrence. Our results show that ECM fungal community shifts are associated with fire recurrence in fire‐prone dry Mediterranean forests, and reveal complex feedbacks among trees, mutualistic fungi and the surrounding environment in these ecosystems.

中文翻译：

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在适应反复火灾的地中海松树林中，外生菌根真菌的多样性下降。

火是与地中海生态系统的演化历史和气候相关的主要干扰，地中海地区的植被已演化出具有火适应性的特征（例如，松露的石蕊）。在地中海森林中，树木和外生菌根（ECM）真菌之间的相互反馈对于生态系统的动态至关重要，可能是反复发生的火灾造成的。我们测试了如何的ECM真菌群落的结构和功能松松和地中海松在地中海生态系统中遭受高火和低火复发的种群之间存在差异，并分析了环境（气候，土壤性质）和树木介导的（血清素）因素的相对贡献。对于两种松树，高发地区的本地和区域真菌多样性均低于低发火地区，尽管前者偏爱某些真菌。P. pinaster的ECM根尖酶活性普遍下降与高火势复发有关，而halepensis没有。火灾复发和与火灾相关的因素（例如气候，土壤特性或树木表型）解释了这些结果。除了气候的主要影响外，树木的火适应性状serotiny还恢复了与火势复发相关的ECM真菌群落结构和功能的很大一部分变化。深度条件（特别是pH，与基岩类型紧密相关）是塑造ECM真菌群落的重要驱动力，但主要是在当地范围内，可能与火灾的复发无关。我们的结果表明，ECM真菌群落的转移与易火的地中海干林中的火灾再发有关，并且揭示了这些生态系统中树木，互助真菌和周围环境之间的复杂反馈。