Data for: Differential responses of soil bacterial communities to a prescribed fire in a paired restored and remnant prairie system

Restoration of prairie and oak savanna systems on former agricultural land is an important effort for improving soil health and ecosystem services. Restored and remnant systems in the same region are often managed using the same strategies, including implementation of prescribed fire. Yet, soil microbial communities and functions in these two types of systems are typically very different due to past land-use history and current plant community composition. In this study, we investigated the responses of soil bacterial communities, enzyme activities and putative functional pathways to the effects of prescribed fire in a paired remnant and restored prairie system located in southwest Michigan, USA. We examined the immediate effects of fire one day after the fire as well as the longer-term effects in a time series extending to 11-months after the fire. Our results indicate that the soil bacterial communities in the remnant were immediately responsive in composition but not in function. Additionally, remnant community composition in burned plots returned to the composition in the control within one month, indicating resiliency in this community. In contrast, soil bacterial communities in the restoration shifted both compositionally and functionally one day after the fire, and continued to differ after 11-months. Past land-use effects on bacterial community composition and site-level heterogeneity, coupled with present-day differences in plant communities and litter quantity, mediated the different responses in the two systems. Our results suggest that land management plans aimed at increasing soil functional resiliency may require different management strategies for restored and remnant prairies.

在既往农用土地上开展草原与栎类稀树草原（oak savanna）生态系统的修复工作，是改善土壤健康状况与提升生态系统服务功能的重要举措。同一区域内的修复型与原生留存型草原生态系统，通常采用包括计划火烧（prescribed fire）在内的相同管理策略。然而，由于既往土地利用历史与当前植物群落组成的差异，这两类生态系统的土壤微生物群落及其功能通常存在显著区别。本研究以美国密歇根州西南部一组配对设置的原生留存型与修复型草原生态系统为研究对象，探究了计划火烧（prescribed fire）对土壤细菌群落、酶活性以及推定功能通路的影响。本研究分别检测了火烧后1天的即时效应，以及长达11个月的时间序列中长期效应。研究结果显示，原生留存型草原的土壤细菌群落仅在群落组成层面产生即时响应，而功能层面未出现显著变化。此外，火烧样地的原生留存群落组成在1个月内即可恢复至对照样地水平，表明该群落具备恢复弹性。与之形成对比的是，修复型草原的土壤细菌群落在火烧后1天即同时在组成与功能层面发生偏移，且在11个月后仍与对照存在显著差异。既往土地利用对细菌群落组成与样地水平异质性的影响，叠加当前植物群落与枯落物量的差异，共同介导了两类生态系统的不同响应模式。本研究结果表明，若以提升土壤功能恢复弹性为目标制定土地管理方案，则需针对修复型与原生留存型草原采用差异化的管理策略。