Key message Under similar site conditions, leaf litter decomposition beneath Central African rainforests was largely driven by average leaf litter quality. Although significant, the additional variability related to litter mixing and to the decomposition environment was limited. Context Under given site conditions, litter decomposition is expected to mainly depend on its average quality. However, the additional impacts of litter diversity as well as of the local decomposition environment remain rather inconclusive. Aims This study investigates the litter mixture effects on decomposition and home-field advantage for two emblematic old growth forest types of the Congo Basin: the Scorodophloeus zenkeri Harms mixed forests and the evergreen Gilbertiodendron dewevrei (De Wild.) J. Léonard monodominant forests. Methods Based on a litterbag experiment, variations in leaf litter mass loss were measured from the eight most important tree species under mixed and monodominant forests and for all possible two-species combinations. Results Remaining mass was largely explained (90%) by a multivariate measure of initial litter quality including 11 functional traits, which performed better than any single leaf litter trait. For the litter mixtures, the average deviation from expectation based on simple additive effects ranged from slightly synergistic (+ 2.56%) to slightly antagonistic (− 0.86%) after 1 and 6 months, respectively. Mixture identity and chemical dissimilarity contributed to explaining the mixing effects, yet the effect of chemical dissimilarity at the whole mixture level was only detected through an interaction with incubation time. In addition, the initial decomposition rates of S. zenkeri and G. dewevrei were accelerated under their own forest type. Conclusion In agreement with the “home-field advantage” theory, our results highlighted that the functional composition of the host forest did have an indirect impact on decomposition. In addition, leaf litter decomposition was mainly controlled by average litter quality, which in turn was closely related to a multivariate measure of green leaf quality. This suggests that increased knowledge of tree species leaf traits in tropical forests would greatly help in better understanding the litter decomposition dynamics.

中文翻译：

---

平均落叶质量推动了刚果盆地 (DRC) 两种截然不同的热带森林类型的单种、混合种和移植落叶的分解

关键信息 在类似的场地条件下，中非雨林下的落叶分解主要是由平均落叶质量驱动的。尽管很重要，但与垃圾混合和分解环境相关的额外可变性是有限的。背景 在给定的场地条件下，预计凋落物分解主要取决于其平均质量。然而，凋落物多样性以及当地分解环境的额外影响仍然相当不确定。目的 本研究调查了凋落物混合对刚果盆地两种具有象征意义的古老生长森林类型的分解和主场优势的影响：Scorodophloeus zenkeri Harms 混交林和常绿的 Gilbertiodendron dewevrei (De Wild.) J. Léonard 单优势林。方法基于垃圾袋实验，对混交林和单一优势林下的八种最重要的树种以及所有可能的两种树种的组合，测量了凋落物质量损失的变化。结果 剩余质量在很大程度上 (90%) 由初始凋落物质量的多变量测量解释，包括 11 个功能性状，其表现优于任何单叶凋落物性状。对于垃圾混合物，基于简单累加效应的平均偏差范围分别在 1 个月和 6 个月后从轻微协同 (+ 2.56%) 到轻微拮抗 (- 0.86%) 不等。混合物特性和化学差异有助于解释混合效应，但化学差异对整个混合物水平的影响只能通过与孵育时间的相互作用来检测。此外，S 的初始分解率。zenkeri 和 G. dewevrei 在它们自己的森林类型下被加速。结论与“主场优势”理论一致，我们的结果强调寄主森林的功能组成确实对分解有间接影响。此外，凋落物分解主要受平均凋落物质量控制，而平均凋落物质量又与绿叶质量的多变量测量密切相关。这表明，增加对热带森林中树种叶子特征的了解将极大地有助于更好地了解凋落物分解动态。凋落物分解主要受平均凋落物质量控制，而平均凋落物质量又与绿叶质量的多变量测量密切相关。这表明，增加对热带森林中树种叶子特征的了解将极大地有助于更好地了解凋落物分解动态。凋落物分解主要受平均凋落物质量控制，而平均凋落物质量又与绿叶质量的多变量测量密切相关。这表明，增加对热带森林中树种叶子特征的了解将极大地有助于更好地了解凋落物分解动态。