Pyrophilic plants respond to post-fire soil conditions in a frequently burned longleaf pine savanna

Fire-plant feedbacks engineer recurrent fires in pyrophilic ecosystems like savannas. The mechanisms sustaining these feedbacks may be related to plant adaptations that trigger rapid responses to fire’s effects on soil. Plants adapted for high fire frequencies should quickly regrow, flower, and produce seeds that mature rapidly and disperse post-fire. We hypothesized that offspring of such plants would germinate and grow rapidly, responding to fire-generated changes in soil nutrients and biota. We conducted an experiment using longleaf pine savanna plants that were paired based on differences in reproduction and survival under annual (“more” pyrophilic) vs. less frequent (“less” pyrophilic) fire regimes. Seeds were planted in different soil inoculations from experimental fires of varying severity. The “more” pyrophilic species displayed high germination rates followed by species specific, rapid growth responses to soil location and fire severity effects on soils. In contrast, the “less”...火-植物反馈机制促成了稀树草原等喜火性（pyrophilic）生态系统中的周期性火灾发生。维持这类反馈的机制，可能与植物对火灾造成的土壤影响产生快速响应的适应性特征相关。适应高火灾频率的植物应当能够快速复生、开花，并产生可快速成熟且在火灾后得以传播的种子。我们提出假说：这类植物的子代能够快速萌发与生长，并响应火灾引发的土壤养分与生物区系变化。我们开展了一项实验，选取长叶松稀树草原的植物类群，依据它们在年度火烧（‘高喜火性’）与低频率火烧（‘低喜火性’）两种火制度（fire regime）下的繁殖与存活差异进行配对分组。将种子种植于取自不同烈度实验火烧的土壤接种物中。‘高喜火性’物种展现出较高的萌发率，随后会依据物种特异性，对土壤位点及火灾烈度对土壤的影响产生快速生长响应。与之相对，‘低喜火性’……