There is a knowledge gap surrounding how drought and wildfire, two increasingly frequent disturbances, will alter soil fungal communities. Moreover, studies that directly compare ambient and drought-treated soil fungal communities in the context of wildfire are exceptionally scarce. We assessed the response and recovery of soil fungal communities and functional guilds in two sites – a grassland and a coastal sage shrubland – after a severe wildfire burned a long-term drought experiment. We collected soil samples at four collection dates over an eight-month period after wildfire and amplified fungal DNA. We predicted that fungal communities within the drought and ambient treatments would differ significantly across collection dates owing to differing responses to post-wildfire conditions. Richness was stable across collection dates, regardless of precipitation treatment, in both sites. Differences between treatments were significant at every collection date with respect to taxonomical community composition. Differences in community composition between collection dates within each treatment were also significant. Additionally, the monotonic trends of drought and ambient communities over time differed in strength and direction. Differences in shrubland functional guild composition across collection dates and contrasting trends suggest a drought-dependent shift after the fire. Overall, we conclude that drought mediates how soil fungal communities respond after a wildfire in the long term, however drought effects may differ across ecosystems.

中文翻译：

---

干旱介导了加州草原和沿海鼠尾草灌丛地野火后土壤真菌群落的反应


关于干旱和野火这两种日益频繁的干扰将如何改变土壤真菌群落，目前存在知识差距。此外，在野火背景下直接比较环境和干旱处理土壤真菌群落的研究非常缺乏。在严重野火烧毁长期干旱实验后，我们评估了两个地点（草地和沿海鼠尾草灌木丛）土壤真菌群落和功能行会的反应和恢复情况。我们在野火发生后八个月的时间内在四个收集日期收集了土壤样本并扩增了真菌 DNA。我们预测，由于对野火后条件的反应不同，干旱和环境处理中的真菌群落在不同收集日期之间会存在显着差异。无论是否进行沉淀处理，这两个地点的丰富度在整个收集日期内都是稳定的。在每个收集日期，在分类群落组成方面，处理之间的差异都很显着。每个处理中收集日期之间的群落组成差异也很显着。此外，随着时间的推移，干旱和周围群落的单调趋势在强度和方向上有所不同。不同收集日期的灌木丛功能行会组成的差异和对​​比趋势表明火灾后发生了依赖于干旱的转变。总体而言，我们得出的结论是，从长远来看，干旱会调节土壤真菌群落在野火后的反应，但干旱对不同生态系统的影响可能有所不同。