Fire is a critical driver of plant and soil nutrient cycling in nutrient-limited ecosystems. Phosphorus (P)-limited and fire-adapted ecosystems can uptake fire-released P, but it is uncertain how post-fire hydrology interacts with fire severity to affect carbon (C) and P cycling in plants and soils. We examined the interactive effects of fire severity and post-fire hydroperiod (defined as the number of days of surface soil inundation in a year for which maximum water depth is a proxy) on soil and plant C and P cycling in intermittent wetlands in south-central Florida. We burned eight wetlands (maximum water depth 0–60 cm), maintaining replicates of four unburned wetlands (maximum water depth 0–48 cm) for reference. We collected surface water, plant and soil chemistries, plant species composition, and % cover during pre- and post-fire periods and measured hydroperiod in all wetlands post-fire. Fire severity—measured as the relative amount of vegetation consumed—was higher in shallower, shorter-hydroperiod wetlands than in deeper, longer-hydroperiod wetlands. Surface water total and dissolved C and nutrient concentrations declined following experimental burns and likely interacted with post-burn flooding. Pre-fire, we detected higher soil C concentrations in longer- than shorter-hydroperiod wetlands; however, soil P was similar among wetlands despite differences in soil C concentrations. Post-fire, soil C and P concentrations were higher in longer-hydroperiod, burned wetlands compared to unburned and shorter-hydroperiod, burned wetlands. Pre- and post-fire plant C and P concentrations were higher than soil C and P concentrations, and post-fire plant C and P were similar among all wetlands regardless of experimental burn treatment. Post-fire plant cover varied with hydroperiod and was largely unaffected by fire, and cover of mineral soil (that is, sand) increased by 6–14 times and bare organic soil increased by 5–30 times post-fire in longer-hydroperiod wetlands. Our results demonstrate that fire severity and post-fire hydrology drive the amount of nutrient release and the extent of post-fire plant succession in nutrient-poor, intermittent wetlands. The impacts of fire on ecosystem recovery are linked to nutrient and water availability.

在营养有限的生态系统中，火是植物和土壤养分循环的关键驱动因素。磷 (P) 限制和适应火灾的生态系统可以吸收火灾释放的 P，但不确定火灾后水文如何与火灾严重程度相互作用以影响植物和土壤中的碳 (C) 和 P 循环。我们研究了火灾严重程度和火灾后水期（定义为一年中以最大水深为代表的表层土壤淹没天数）对南部间歇性湿地土壤和植物 C 和 P 循环的交互影响。佛罗里达州中部。我们烧毁了八个湿地（最大水深 0-60 厘米），保留了四个未烧毁湿地（最大水深 0-48 厘米）的复制品以供参考。我们收集了地表水、植物和土壤化学成分、植物物种组成、火灾前和火灾后的覆盖率百分比以及火灾后所有湿地的测量水周期。火灾的严重程度——以消耗的植被的相对数量来衡量——在较浅、水周期较短的湿地中比在较深、水周期较长的湿地中更高。地表水总和溶解的 C 和养分浓度在实验性燃烧后下降，并且可能与燃烧后的洪水相互作用。火灾前，我们检测到水周期较长的湿地土壤碳浓度高于水周期较短的湿地；然而，尽管土壤 C 浓度存在差异，但湿地之间的土壤 P 相似。火灾后，与未燃烧和较短水周期的燃烧湿地相比，较长水文周期的燃烧湿地的土壤 C 和 P 浓度更高。火灾前后植物C、P浓度均高于土壤C、P浓度，无论实验烧伤处理如何，火灾后植物 C 和 P 在所有湿地中都相似。火后植物盖度随水期变化，基本不受火灾影响，火后较长水期湿地矿质土壤（即沙子）覆盖率增加6-14倍，裸露有机土壤增加5-30倍. 我们的研究结果表明，火灾严重程度和火灾后水文推动了营养物贫乏、间歇性湿地中的养分释放量和火灾后植物演替的程度。火灾对生态系统恢复的影响与养分和水的可用性有关。沙) 增加了 6-14 倍，裸露的有机土壤在较长水周期湿地火灾后增加了 5-30 倍。我们的研究结果表明，火灾严重程度和火灾后水文推动了营养物贫乏、间歇性湿地中的养分释放量和火灾后植物演替的程度。火灾对生态系统恢复的影响与养分和水的可用性有关。沙) 增加了 6-14 倍，裸露的有机土壤在较长水周期湿地火灾后增加了 5-30 倍。我们的研究结果表明，火灾严重程度和火灾后水文推动了营养物贫乏、间歇性湿地中的养分释放量和火灾后植物演替的程度。火灾对生态系统恢复的影响与养分和水的可用性有关。