Background and aims Fires can alter the elemental stoichiometry of ecosystems, reflecting altered patterns of biogeochemical cycling in the post-fire environment. However, elements other than carbon (C), nitrogen (N), and phosphorus (P) have rarely been studied in this context. Thus, we aimed to expand the understanding of fire’s stoichiometric and biogeochemical effects to encompass a broader suite of biogenic elements. Methods We compared the stoichiometric ratios of C, N, P, potassium (K), sodium (Na), magnesium (Mg), and sulfur (S) in soil, plant litter, and beetles ( Thalycrodes pulchrum ) between forest plots that have been burned biennially at low intensity since 1972 and plots that have remained unburned. Results Multi-element stoichiometry differed strongly between the fire regimes. Low intensity biennial burning was associated with depletion of C, N, and S relative to P, K, and to a small extent Mg and Na, in soil and litter. The stoichiometry of T. pulchrum biomass was not significantly affected by fire regime, but fire regime-associated variation in the stoichiometry of T. pulchrum biomass was positively correlated with the fire-induced stoichiometric shifts in soil. Conclusions The effects of low intensity prescribed fire on ecological stoichiometry extend to Na, K, Mg, and S in ways consistent with the respective potentials of these elements to volatilize during fire or accumulate in the absence of fire. These effects vary among ecosystem components in a manner that reveals the importance of biological processes and constraints as factors that determine the nature, magnitude, and potential consequences of the stoichiometric signatures of fire regimes. We conclude that long-term changes in fire regime can disrupt or even decouple the biogeochemical cycles of numerous biogenic elements in the soil–plant system.

中文翻译：

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近来频繁的火灾改变了湿桉树林的多元素化学计量

背景和目标 火灾可以改变生态系统的元素化学计量，反映火灾后环境中生物地球化学循环模式的改变。然而，除碳 (C)、氮 (N) 和磷 (P) 以外的元素在这方面很少被研究。因此，我们旨在扩大对火的化学计量和生物地球化学影响的理解，以涵盖更广泛的生物元素。方法 我们比较了土壤、植物凋落物和甲虫 (Thalycrodes pulchrum) 中碳、氮、磷、钾 (K)、钠 (Na)、镁 (Mg) 和硫 (S) 的化学计量比。自 1972 年以来每两年以低强度燃烧，而地块仍未燃烧。结果 不同火情的多元素化学计量差异很大。低强度两年一度的燃烧与土壤和凋落物中的 C、N 和 S 相对于 P、K 以及少量 Mg 和 Na 的消耗有关。T. pulchrum 生物量的化学计量不受火势的显着影响，但与火势相关的 T. pulchrum 生物量的化学计量变化与土壤中火引起的化学计量变化呈正相关。结论 低强度规定火灾对生态化学计量的影响扩展到 Na、K、Mg 和 S，其方式与这些元素在火灾中挥发或在没有火灾时积累的各自潜力一致。这些影响因生态系统组成部分而异，其方式揭示了生物过程和限制因素的重要性，这些因素决定了生态系统的性质、大小、以及火势的化学计量特征的潜在后果。我们得出结论，火势的长期变化会破坏甚至解耦土壤 - 植物系统中众多生物元素的生物地球化学循环。