Aim: Biodiversity across different scales provides multidimensional
insurance for ecosystem functioning. Although the effects of biodiversity
on ecosystem multifunctionality are well recorded in local communities,
they remain poorly understood across scales (from local to larger spatial
scales). This study evaluates how multiple attributes of biodiversity
maintain ecosystem multifunctionality from local to regional scales,
across diverse environmental gradients. Location: North-eastern China.
Time period: 2017. Major taxa studied: Woody plants. Methods: We define
multifunctionality using both averaged and modified multiple threshold
approaches. Multiple dimensions of biodiversity across varying spatial
scales were measured within the framework of Hill‒Chao numbers. Using
variance decomposition, linear mixed models, and structural equation
modeling, we explored how multiple attributes of tree diversity at varying
spatial scales affect multifunctionality, and how these relationships are
modulated by environmental drivers.Results: We found that both α- and
β-diversity are critical for regional community multifunctionality, while
the relationships between species, functional, and phylogenetic diversity
and multifunctionality decoupled across spatial scales and thresholds of
ecosystem functioning. Phylogenetic β-diversity and species α-diversity
are respectively more important for promoting high and moderate threshold
multifunctionality (e.g., EMFT90 and EMFT50) in regional communities.
Environmental drivers typically have stronger effects than biodiversity on
multifunctionality. Soil and climatic conditions had either direct effects
on multifunctionality, or indirect ones mediated by species α-diversity.
Environmental heterogeneity is important for high threshold
multifunctionality, exerting directly and indirectly through phylogenetic
β-diversity. Latitude not only directly influences multifunctionality but
also modulates it through species α-diversity and phylogenetic
β-diversity. Main conclusions: This study underscores the positive effects
of biodiversity on multifunctionality across multiple dimensions. Based on
our findings, we conclude that any design of a forested landscape that is
aimed at maximizing multifunctionality should consider maintaining high
local diversity as well as forest community heterogeneity at varying
scales.