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

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.

Using avian functional traits to assess the impact of land-cover change on ecosystem processes linked to resilience in tropical forests

“…Standard approaches to understanding environmental change based solely on species richness and composition may overlook important implications for ecosystem processes, leading to calls for FD to be more explicitly considered in biodiversity conservation strategies [13,68,69]. Our results support this view, yet also highlight how treatment of FD can be improved to provide greater insights.…”

“…The resulting loss and degradation of primary forests typically reduces species richness, and increases biological homogenization, across a wide range of taxonomic groups [7][8][9][10][11]. However, it is becoming increasingly clear that the raw number and even heterogeneity of species surviving in communities may be poor indices of functional aspects of biodiversity [12,13], including the trophic interactions needed to maintain recruitment and gene flow in rainforest trees [14,15]. Consequently, the implication of land-cover change for the health and stability of tropical forest ecosystems, and their ability to recover from human-driven perturbations, is still largely unclear [16][17][18].…”

“…One advantage of quantifying multiple functional traits as continuous variables, rather than the categories adopted by many studies [13,18], is that we can visualize the effects of land-cover change on the structure of communities. We plotted the species in multivariate trait space (hereafter termed 'morphospace') to assess the volume and density of functional traits in different land-cover categories.…”

Changes in the location of biodiversity–ecosystem function hot spots across the seafloor landscape with increasing sediment nutrient loading

“…Many BEF experiments document the importance of particular species on function (identity effects), although the functional consequence of the loss of these species can be dependent on the community that remains [22]. We also found functional and community diversity measures to be important [54], with functional richness the most consistent biodiversity predictor in the BEF models. Functional richness was based on multiple traits and represents the volume of trait space within the community.…”

Functional traits in agriculture: agrobiodiversity and ecosystem services

“…Gagic et al [42] provided an initial step by calculating functional trait diversity based on a mix of continuous and categorical traits to show that functional trait metrics are superior to taxonomic measures in linking diversity to several ecosystem functions. Although this study included some important agroecosystem services (e.g., pollination and pest control), it was not specifically focused on agriculture.…”