Smith Gabriel Reuben, Edy Lucy C, Peay Kabir G
Department of Biology, Stanford University, Stanford, CA, USA.
Global Ecosystem Ecology, Department of Environmental Systems Science, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland.
Mol Ecol. 2021 Feb;30(3):844-854. doi: 10.1111/mec.15767. Epub 2020 Dec 15.
Wildfire affects our planet's biogeochemistry both by burning biomass and by driving changes in ecological communities and landcover. Some plants and ecosystem types are threatened by increasing fire pressure while others respond positively to fire, growing in local and regional abundance when it occurs regularly. However, quantifying total ecosystem response to fire demands consideration of impacts not only on aboveground vegetation, but also on soil microbes like fungi, which influence decomposition and nutrient mineralization. If fire-resistant soil fungal communities co-occur with similarly adapted plants, these above- and belowground ecosystem components should shift and recover in relative synchrony after burning. If not, fire might decouple ecosystem processes governed by these different communities, affecting total functioning. Here, we use a natural experiment to test whether fire-dependent ecosystems host unique, fire-resistant fungal communities. We surveyed burned and unburned areas across two California ecosystem types with differing fire ecologies in the immediate aftermath of a wildfire, finding that the soil fungal communities of fire-dependent oak woodlands differ from those of neighbouring mixed evergreen forests. We discovered furthermore that the latter are more strongly altered compositionally by fire than the former, suggesting that differences in fungal community structure support divergent community responses to fire across ecosystems. Our results thus indicate that fire-dependent ecosystems may host fire-resistant fungal communities.
野火通过燃烧生物质以及推动生态群落和土地覆盖的变化来影响地球的生物地球化学。一些植物和生态系统类型受到火灾压力增加的威胁，而其他一些则对火灾有积极反应，当火灾定期发生时，它们在当地和区域范围内大量生长。然而，要量化生态系统对火灾的总体反应，不仅需要考虑对地上植被的影响，还需要考虑对土壤微生物（如真菌）的影响，因为真菌会影响分解和养分矿化。如果耐火土壤真菌群落与适应性相似的植物同时出现，那么这些地上和地下生态系统组成部分在燃烧后应该会相对同步地发生变化和恢复。如果不是这样，火灾可能会使由这些不同群落控制的生态系统过程脱节，影响整体功能。在这里，我们利用一项自然实验来测试依赖火灾的生态系统是否拥有独特的耐火真菌群落。在一场野火刚结束后，我们对加利福尼亚州两种具有不同火灾生态的生态系统类型中的燃烧区域和未燃烧区域进行了调查，发现依赖火灾的橡树林地的土壤真菌群落与相邻的混合常绿森林的不同。我们还发现，后者在火灾后组成上的变化比前者更强烈，这表明真菌群落结构的差异支持了不同生态系统对火灾的不同群落反应。因此，我们的结果表明，依赖火灾的生态系统可能拥有耐火真菌群落。
