As the range of bark beetles expands into new forests and woodlands, the need to understand their effects on multiple trophic levels becomes increasingly important. To date, much attention has been paid to the aboveground processes affected by bark beetle infestation, with a focus on photoautotrophs and ecosystem level processes. However, indirect effects of bark beetle on belowground processes, especially the structure and function of soil microbiota remains largely a black box. Our study examined the impacts of bark beetle-induced tree mortality on soil microbial community structure and function using high-throughput sequencing of the soil bacterial and fungal communities and measurements of extracellular enzyme activities. The results suggest bark beetle infestation affected edaphic conditions through increased soil water content, pH, electrical conductivity, and carbon/nitrogen ratio and altered bulk and rhizosphere soil microbial community structure and function. Finally, increased enzymatic activity suggests heightened microbial decomposition following bark beetle infestation. With this increase in enzymatic activity, nutrients trapped in organic substrates may become accessible to seedlings and potentially alter the trajectory of forest regeneration. Our results indicate the need for incorporation of microbial processes into ecosystem level models.

IMPORTANCE Belowground impacts of bark beetle infestation have not been explored as thoroughly as their aboveground counterparts. In order to accurately model impacts of bark beetle-induced tree mortality on carbon and nutrient cycling and forest regeneration, the intricacies of soil microbial communities must be examined. In this study, we investigated the structure and function of soil bacterial and fungal communities following bark beetle infestation. Our results show bark beetle infestation to impact soil conditions, as well as soil microbial community structure and function.

随着树皮甲虫的范围扩大到新的森林和林地，了解它们对多种营养水平的影响的需求变得越来越重要。迄今为止，人们对树皮甲虫侵扰的地上过程给予了极大关注，重点是光养自养生物和生态系统水平的过程。然而，树皮甲虫对地下过程的间接影响，特别是土壤微生物群的结构和功能在很大程度上仍是一个黑匣子。我们的研究使用土壤细菌和真菌群落的高通量测序和细胞外酶活性的测定方法，研究了树皮甲虫引起的树木死亡率对土壤微生物群落结构和功能的影响。结果表明，通过增加土壤水分，pH，电导率，碳氮比以及改变的土壤微生物和根际土壤微生物群落结构和功能。最后，增加的酶活性表明在树皮甲虫侵扰后微生物分解增加。随着酶活性的增加，留在有机基质中的养分可能会变得易于幼苗生长，并可能改变森林再生的轨迹。我们的结果表明需要将微生物过程纳入生态系统级模型中。被困在有机基质中的养分可能会变得易于幼苗生长，并有可能改变森林再生的轨迹。我们的结果表明需要将微生物过程纳入生态系统级模型中。被困在有机基质中的养分可能会变得易于幼苗生长，并有可能改变森林再生的轨迹。我们的结果表明需要将微生物过程纳入生态系统级模型中。

重要事项尚未充分探索树皮甲虫侵害的地下影响及其对地的影响。为了准确地模拟树皮甲虫引起的树木死亡率对碳和养分循环以及森林再生的影响，必须检查土壤微生物群落的复杂性。在这项研究中，我们调查了树皮甲虫侵染后土壤细菌和真菌群落的结构和功能。我们的研究结果表明，树皮甲虫侵染会影响土壤条件，以及土壤微生物群落结构和功能。