Edited by Nils C. Stenseth, University of Oslo, Oslo, Norway, and approved March 12, 2019 (received for review September 11, 2018)
Biodiversity is declining globally, but its different taxonomic, functional, and evolutionary attributes are doing so at a different pace. Understanding how these attributes influence ecosystem functioning is crucial to better predict the ecological consequences of biodiversity loss. Based on a survey of 123 drylands worldwide, our results highlight the phylogenetic and functional attributes of subordinate species as key drivers of the provision of multiple ecosystem functions simultaneously (multifunctionality). Our study expands our understanding of the relationship between biodiversity and multifunctionality by identifying the diversity of early diverging lineages and functional redundancy as important biodiversity attributes to prioritize in conservation and restoration programs aimed at promoting dryland multifunctionality worldwide.
Biodiversity encompasses multiple attributes such as the richness and abundance of species (taxonomic diversity), the presence of different evolutionary lineages (phylogenetic diversity), and the variety of growth forms and resource use strategies (functional diversity). These biodiversity attributes do not necessarily relate to each other and may have contrasting effects on ecosystem functioning. However, how they simultaneously influence the provision of multiple ecosystem functions related to carbon, nitrogen, and phosphorus cycling (multifunctionality) remains unknown. We evaluated the effects of the taxonomic, phylogenetic, and functional attributes of dominant (mass ratio effects) and subordinate (richness effect) plant species on the multifunctionality of 123 drylands from six continents. Our results highlight the importance of the phylogenetic and functional attributes of subordinate species as key drivers of multifunctionality. In addition to a higher taxonomic richness, we found that simultaneously increasing the richness of early diverging lineages and the functional redundancy between species increased multifunctionality. In contrast, the richness of most recent evolutionary lineages and the functional and phylogenetic attributes of dominant plant species (mass ratio effects) were weakly correlated with multifunctionality. However, they were important drivers of individual nutrient cycles. By identifying which biodiversity attributes contribute the most to multifunctionality, our results can guide restoration efforts aiming to maximize either multifunctionality or particular nutrient cycles, a critical step to combat dryland desertification worldwide.
↵1Y.L.B.-P., S.S., and N.G. contributed equally to this work.
Author contributions: Y.L.B.-P., S.S., N.G., and F.T.M. designed research; Y.L.B.-P., S.S., and N.G. performed research; R.T. and M.B. contributed analytic tools; F.T.M. coordinated data acquisition; Y.L.B.-P. analyzed data; and Y.L.B.-P., S.S., N.G., R.T., M.B., and F.T.M. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
Data deposition: Data are available through the Figshare repository, https://figshare.com/s/08b538101fe252a2e879, https://figshare.com/s/5c951b7f82dd551737b8.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1815727116/-/DCSupplemental.
Published under the PNAS license.
