Functional identity and diversity of animals predict ecosystem functioning better than species-based indices

TLDR

Biodiversity loss threatens ecosystem functioning, and a functional trait framework has been proposed to better understand this relationship, yet it has rarely been tested beyond plants. The study aimed to compare trait‑based and taxonomic approaches in predicting ecosystem functions across animal groups. Researchers analysed eight datasets, including five animal groups, to assess how well trait‑based indices predict seven below‑ and above‑ground ecosystem functions. Trait‑based indices explained ecosystem function better than species richness or abundance, with single‑ and multi‑trait frequency distributions being the strongest predictors, indicating that function depends on trait identity and complementarity rather than species number.

Abstract

Drastic biodiversity declines have raised concerns about the deterioration of ecosystem functions and have motivated much recent research on the relationship between species diversity and ecosystem functioning. A functional trait framework has been proposed to improve the mechanistic understanding of this relationship, but this has rarely been tested for organisms other than plants. We analysed eight datasets, including five animal groups, to examine how well a trait-based approach, compared with a more traditional taxonomic approach, predicts seven ecosystem functions below- and above-ground. Trait-based indices consistently provided greater explanatory power than species richness or abundance. The frequency distributions of single or multiple traits in the community were the best predictors of ecosystem functioning. This implies that the ecosystem functions we investigated were underpinned by the combination of trait identities (i.e. single-trait indices) and trait complementarity (i.e. multi-trait indices) in the communities. Our study provides new insights into the general mechanisms that link biodiversity to ecosystem functioning in natural animal communities and suggests that the observed responses were due to the identity and dominance patterns of the trait composition rather than the number or abundance of species per se .