Wildfires and climate change increasingly are transforming vegetation composition and structure, and postfire management may have long‐lasting effects on ecosystem reorganization. Postfire aerial seeding treatments are commonly used to reduce runoff and soil erosion, but little is known about how seeding treatments affect native vegetation recovery over long periods of time, particularly in type‐converted forests that have been dramatically transformed by the effects of repeated, high‐severity fire. In this study, we analyze and report on a rare long‐term (23‐year) dataset that documents vegetation dynamics following a 1996 post‐fire aerial seeding treatment and a subsequent 2011 high‐severity reburn in a dry conifer landscape of northern New Mexico, USA. Repeated surveys between 1997 and 2019 of 49 permanent transects were analyzed for differences in vegetation cover, richness, and diversity between seeded and unseeded areas, and to characterize the development of seeded and unseeded vegetation communities through time and across gradients of burn severity, elevation, and soil‐available water capacity. Seeded plots showed no significant difference in bare ground cover during the initial years postfire relative to unseeded plots. Postfire seeding led to a clear and sustained divergence in herbaceous community composition. Seeded plots had a much higher cover of non‐native graminoids, primarily Bromus inermis, a likely contaminant in the seed mix. High‐severity reburning of all plots in 2011 reduced native graminoid cover by half at seeded plots compared with both prefire levels and with plots that were unseeded following the initial 1996 fire. In addition, higher fire severity was associated with increased non‐native graminoid cover and reduced native graminoid cover. This study documents fire‐driven ecosystem transformation from conifer forest into a shrub‐and‐grass‐dominated system, reinforced by aerial seeding of grasses and high‐severity reburning. This unique long‐term dataset illustrates that post‐fire seeding carries significant risks of unwanted non‐native species invasions that persist through subsequent fires—thus alternative postfire management actions merit consideration to better support native ecosystem resilience given emergent climate change and increasing disturbance. This study also highlights the importance of long‐term monitoring of postfire vegetation dynamics, as short‐term assessments miss key elements of complex ecosystem responses to fire and postfire management actions.

中文翻译：

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严重火灾和空中播种后新墨西哥州黄松景观的多年代植被转变


野火和气候变化日益改变植被组成和结构，火后管理可能对生态系统重组产生长期影响。火后空中播种处理通常用于减少径流和土壤侵蚀，但对于播种处理如何长期影响原生植被恢复知之甚少，特别是在经过反复、高强度火灾影响而发生巨大转变的类型转换森林中。 ‐严重火灾。在这项研究中，我们分析并报告了一个罕见的长期（23 年）数据集，该数据集记录了新墨西哥州北部干燥针叶树景观中 1996 年火灾后空中播种处理和随后的 2011 年高强度再燃烧后的植被动态，美国。 1997 年至 2019 年间，对 49 个永久性样带进行了重复调查，分析了播种区和未播种区之间植被覆盖、丰富度和多样性的差异，并描述了播种和未播种植被群落随时间和烧伤严重程度、海拔、坡度梯度的发展特征。和土壤可用水容量。相对于未播种的地块，在火灾后最初几年，播种的地块裸地覆盖没有显着差异。火后播种导致草本群落组成出现明显且持续的差异。播种地块的非本地禾本科植物覆盖率要高得多，主要是无芒雀麦，它可能是种子混合物中的污染物。与火灾前水平和 1996 年初次火灾后未播种的地块相比，2011 年所有地块的高强度重烧使播种地块的原生禾本科植物覆盖率减少了一半。此外，较高的火灾严重程度与非本地禾本科植物覆盖率的增加和本地禾本科植物覆盖率的减少有关。 这项研究记录了火驱动的生态系统从针叶林转变为以灌木和草为主的系统，并通过空中播种草和高强度的再燃烧得到加强。这个独特的长期数据集表明，火灾后播种会带来非本地物种入侵的重大风险，这种入侵会在随后的火灾中持续存在，因此考虑到气候变化和干扰的增加，值得考虑采取替代性的火灾后管理行动，以更好地支持本地生态系统的恢复能力。这项研究还强调了长期监测火后植被动态的重要性，因为短期评估遗漏了复杂的生态系统对火灾和火后管理行动的反应的关键要素。