Multitrophic diversity and biotic associations influence subalpine forest ecosystem multifunctionality

Biodiversity across multiple trophic levels is required to maintain multiple ecosystem functions. Yet it remains unclear how multitrophic diversity and species interactions regulate ecosystem multifunctionality. Here, combining data from 9 different trophic groups (including trees, shrubs, herbs, leaf mites, small mammals, bacteria, pathogenic fungi, saprophytic fungi, and symbiotic fungi) and 13 ecosystem functions related to supporting, provisioning, and regulating services, we used a multitrophic perspective to evaluate the effects of elevation, diversity, and network complexity on scale-dependent subalpine forest multifunctionality. Our results demonstrated that elevation and soil pH significantly modified species composition and richness across multitrophic groups and influenced multiple functions simultaneously. We present evidence that species richness across multiple trophic groups had stronger effects on multifunctionality than species richness at any single trophic level. Moreover, biotic associations, indicating the complexity of trophic networks, were positively associated with multifunctionality. The relative effects of diversity on multifunctionality increased at the scale of the larger community compared to a scale accounting for neighboring interactions. Our results highlight the paramount importance of scale- and context-dependent multitrophic diversity and interactions for a better understanding of mountain ecosystem multifunctionality in a changing world.

Automated summary

Biodiversity and species interactions have significant effects on ecosystem multifunctionality. Elevation and soil pH can modify species composition and richness, and influence multiple ecosystem functions simultaneously. Species richness across multiple trophic groups has stronger effects on multifunctionality than species richness at any single trophic level. Biotic associations are positively associated with multifunctionality. The relative effects of diversity on multifunctionality increase at the scale of the larger community.