Data from: Disentangling relationships between plant diversity and decomposition processes under forest restoration

Biodiversity has been elucidated to be one of the major factors sustaining ecosystem functioning. The vast majority of studies showing a relationship between biodiversity and ecosystem functioning have come from experiments, and this knowledge has not yet been applied to most real-world cases of conservation and management. This is especially true in forest ecosystems, characterized by the dominance of long-lived organisms (trees) and high levels of structural complexity and environmental heterogeneity. To apply biodiversity–function relationships to actual forest management, there are several issues to be considered. These include employing a cross-taxon perspective, as some functions (e.g. soil biogeochemical processes) cannot be maintained by a narrow set of organisms, as is usually the case with experimental systems. More specifically, although the interaction between above- and below-ground diversity is important for many functions in forests, there are few studies that evaluated the roles of diversity in both subsystems in a manner that could be informative in practice. To evaluate the roles of above- and below-ground diversity to support natural soil ecosystem functions, we conducted a decomposition experiment in the northern forests of Japan, which are currently under restoration management. The restoration area consists of mosaics of different vegetation types by various revegetation activities and establishment of ungulate exclosures. Using structural equation modelling and linear mixed-effects models, we assessed direct and indirect pathways from diversity to functions by focusing on both of taxonomic and functional diversity indices. To put our findings into practice, we utilized a trait-based approach, which provides a link between the functional consequences of human influences and ecosystem structure. We found little direct effects of tree diversity on below-ground functions such as decomposition rate and litter stabilization. However, once the diversities of understorey herbaceous plants and soil fungi were considered as a possible mediating explanatory factor, we found a significant effect of tree diversity to indirectly support these functions by supporting these other types of biodiversity. Particularly, we found that the models based on functional trait diversity, rather than on taxonomic species richness, best explained the variation in below-ground processes. Synthesis and applications. Forest restoration in the northern forests of Japan has had no explicit objective to restore soil functions. Nevertheless, afforestation, and the associated increase in tree diversity as a measure of forest restoration, was, although often unintentionally, proven effective for the maintenance of multiple ecosystem functions, such as soil biogeochemical processes. This finding suggests a great potential for management to make local tree assemblages functionally dissimilar and diverse for the sake of supporting and enhancing fundamental ecosystem functions in forests.

生物多样性被证实为维持生态系统功能的关键支撑因子之一。绝大多数揭示生物多样性与生态系统功能之间关联的研究均源自受控实验，而此类研究结论尚未应用于绝大多数现实世界的保护与管理场景，这一点在森林生态系统中尤为突出——这类生态系统以长寿生物（树木）为优势类群，且具有极高的结构复杂性与环境异质性。若要将生物多样性-功能关联的研究成果应用于实际森林管理，需考量多方面问题：其一，需采用跨类群研究视角，因为部分生态功能（如土壤生物地球化学过程（soil biogeochemical processes））无法如实验系统那般，仅通过有限的生物类群得以维持。具体而言，尽管地上与地下生物多样性的相互作用对森林的多项功能至关重要，但目前鲜有研究以具备实践指导价值的方式，同时评估这两个子系统中生物多样性的作用。为评估地上与地下生物多样性在支撑自然土壤生态系统功能中的作用，我们在当前正处于修复管理阶段的日本北部森林中开展了一项分解实验（decomposition experiment）。该修复区域因各类植被重建活动以及有蹄类动物排除区（ungulate exclosures）的设置，形成了不同植被类型镶嵌分布的格局。本研究借助结构方程模型（structural equation modelling）与线性混合效应模型（linear mixed-effects models），以分类学与功能多样性指数为核心分析维度，解析了生物多样性对生态功能的直接与间接作用路径。为将研究发现转化为实践应用，我们采用了基于性状的研究方法（trait-based approach），该方法可搭建人类活动的功能效应与生态系统结构之间的关联桥梁。研究结果显示，树木多样性对分解速率、凋落物固持（litter stabilization）等地下生态功能几乎无直接影响。但当将林下草本植物（understorey herbaceous plants）与土壤真菌（soil fungi）的多样性作为潜在中介解释因子纳入分析后，我们发现树木多样性可通过支撑其他类群的生物多样性，间接对上述地下生态功能产生显著的正向作用。尤为关键的是，相较于基于分类学物种丰富度的模型，以功能性状多样性为基础的模型能够更好地解释地下生态过程的变异。综合与应用：日本北部森林的修复工程此前并未将恢复土壤功能列为明确目标，但作为森林修复手段的造林（afforestation）措施及其伴随的树木多样性提升，即便往往并非有意为之，已被证实可有效维持土壤生物地球化学过程等多项生态系统功能。这一发现表明，通过调整本地树木群落的功能组成与多样性水平，使其具备功能异质性与更高的多样性，可有效支撑并强化森林的核心生态系统功能，森林管理具备极大的应用潜力。

搜集汇总

背景与挑战

背景概述

该数据集源自一项森林恢复研究，旨在探究植物多样性与分解过程之间的关系。研究发现，树多样性通过间接支持林下植物和土壤真菌的多样性来影响分解功能，且功能性状多样性比物种丰富度更能解释地下过程的变化，为森林管理提供了实践指导。