DOI: 10.5061/dryad.7775d
title: Data from: Disentangling relationships between plant diversity and decomposition processes under forest restoration

description: 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.
description: Plant species list and
 soil datadata.xlsx