Collaborative Research: Role of soil microbiome resilience in ecosystem recovery following severe wildfire

野火是健康森林生态系统的自然特征。人们之所以感到关切，是因为随着我们的气候变暖，这些事件的频率和强度正在增加。在野火的诸多影响中，野火干扰影响了森林土壤中存在的微生物，这些微生物催化了一系列关键的生态系统过程，从树苗的建立到碳和氮的循环。迄今为止的研究表明，野火改变了土壤微生物群落的组成，但缺乏关于美国西部森林日益严重的野火将如何影响土壤微生物群落的恢复以及对森林生态系统的级联影响的关键信息。这项研究使用了一个独特的系列在北方科罗拉多的小松树林烧伤桩疤痕作为代理土壤环境的十年恢复严重的野火。这项工作将使用各种微生物和地球化学分析，以确定火灾后50年内土壤化学和微生物群落的变化。在这里获得的见解将有助于美国西部严重野火后的森林管理，并将被纳入参与研究机构的新教育机会。该项目将丰富研究人员教授的各种课程，包括为本科生和研究生提供培训机会，并为森林管理人员提供合作推广以及公共宣传活动。这项研究将调查土壤微生物组的弹性（即，它们恢复到火灾前水平的能力），（2）微生物组结构变化的功能意义，（3）改变土壤微生物组通过根际相互作用支持树木再生的能力。总之，这项研究将测试这一假设，即改变土壤的化学和物理性质，使土壤微生物组在严重的野火后达到一种交替的稳定状态，这对建立新的松树幼苗和随后的生态系统恢复具有影响。为了测试这一点，这项工作利用了一个独特的实验机会，包括整个森林生态系统的燃烧堆疤痕，从而确保燃料类型和负载，海拔，气候和方面的时序控制。此外，该方法集成了多种分析工具，包括土壤微生物的宏基因组查询，土壤化学的质谱表征和植被操作温室实验。总之，我们的研究结果将代表对火灾后50年恢复期内焚烧土壤微生物群落恢复能力的首次深入了解，该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Wildfire is a natural feature of healthy forest ecosystems. There is concern because the frequency and intensity of these events are increasing as our climate warms. Among their many impacts, wildfire disturbances impact the microorganisms present in forest soils that catalyze a series of key ecosystem processes, ranging from the establishment of tree seedlings to the cycling of carbon and nitrogen. Research to date has revealed that the composition of soil microbiomes is altered by wildfire, but critical information is lacking on how increasingly severe wildfires in western US forests will affect the recovery of soil microbial communities, with cascading impacts on forest ecosystems. This research uses a unique series of burn pile scars in a lodgepole pine forest in northern Colorado as a proxy for the decadal recovery of the soil environment following severe wildfire. The work will use diverse microbiological and geochemical analyses to determine how soil chemistry and microbiomes change up to 50-years following fire. Insights gained here will assist with forest management following severe wildfire in the western US and will be incorporated into new educational opportunities at the participating research institutions. The project will enrich a variety of courses taught by the researchers, include training opportunities for undergraduate and graduate students, and provide cooperative extension to forest managers as well as public outreach activities.There is an increasing appreciation that changing wildfire regimes may drive long-term alterations in both above- and below-ground ecosystem structure. This research will investigate the resilience of soil microbiomes (i.e., their ability to return to pre-fire levels) following severe wildfire in lodgepole pine forests, (2) the functional implications of shifts in microbiome structure, and (3) the ability of altered soil microbiomes to support tree regeneration via rhizosphere interactions. Together, this research will test the hypothesis that altered soil chemical and physical properties drive the soil microbiome to an alternate steady state following severe wildfire, with implications for the establishment of new pine seedlings and subsequent ecosystem recovery. To test this, the work leverages a unique experimental opportunity consisting of burn pile scars throughout a forest ecosystem, thus ensuring that the chrono-sequence controls for fuel type and load, elevation, climate, and aspect. Furthermore, the approach integrates diverse analytical tools including metagenomic interrogations of soil microbiomes, mass-spectrometry characterization of soil chemistry, and vegetation manipulation greenhouse experiments. Together, our results will represent the first insights into the extent of resilience of burned soil microbiomes across a 50-year post-fire recovery period, and the ability of lodgepole pine seedlings to recruit beneficial rhizosphere communities that aid in tree re-establishment.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.