Tropical rain forests worldwide are affected by anthropogenic disturbances, and secondary forests that develop afterwards are often dominated by pioneer tree species, but the consequences of different anthropogenic disturbances on nutrient cycling are poorly understood. Because most nutrient cycling in tropical rain forests occurs through litterfall and in the soil organic layer, we measured litterfall of a widespread and dominant pioneer tree, okoume (Aucoumea klaineana, Burseraceae) in Gabon, in one forest previously disturbed by logging and in another by agriculture. Litterfall of okoume trees, measured over 14 months, was 18.2 Mg ha⁻¹ year⁻¹ in the formerly logged forest, which was 72.6% greater than in the forest more recently disturbed by agriculture (10.6 Mg ha⁻¹ year⁻¹). Litter decomposition rates were more rapid in the formerly logged forest, and this may explain why litter thickness was 32% lower in the formerly logged forest, despite the greater litterfall within it. Our results highlight that two widespread anthropogenic disturbances in Gabonese rain forests have significantly different consequences on litterfall of a dominant tree and therefore are likely to have different effects on nutrient cycling and forest ecosystem function.

中文翻译：

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不同的人为干扰对加蓬主要的先驱雨林树凋落物的影响

世界各地的热带雨林都受到人为干扰的影响，后来发展起来的次生林通常被先锋树种占主导地位，但人们对不同人为干扰对养分循环的影响知之甚少。由于热带雨林中的大多数养分循环都是通过凋落物和土壤有机层发生的，因此我们测量了加蓬一棵先前受伐木干扰而另一处受干扰的森林中广泛分布且占主导地位的先锋树okoume（Aucumea klaineana，Burseraceae）的凋落物。农业。在14个月内测得的古猿树木的凋落物为18.2 Mg ha - ¹ 年^-1在以前伐木的森林中，比最近受农业干扰（10.6 Mg ha - ¹ 年^-1）的森林高72.6％。在以前伐木的森林中，凋落物分解的速度更快，这也许可以解释为什么在过去伐木的森林中，凋落物的厚度要低32％。我们的结果表明，加蓬雨林中两种广泛的人为干扰对优势树的凋落物产生了显着不同的后果，因此可能对养分循环和森林生态系统功能产生不同的影响。