Changes in metazoan functional diversity during the Cambrian Sinsk Event

A dataset of Cambrian skeletal metazoans, detailing their species richness and functional traits across a number of time bins. We examined functional diversity changes across a mass extinction event. Enclosed R scripts are fully annotated to facilitate the reproduction of all analyses and figures. 

Methods
Functional diversity analyses were performed in the R environment (Version 2.2.2) using the package mFD (multifaceted Functional Diversity) (Magneville et al., 2022; R Core Team, 2022; see Supplementary Materials). Trait-based distances between taxonomic groups were calculated using the Gower distance metric, since this can accommodate both continuous and categorical variables (de Bello et al., 2021).

Principal Coordinates Analysis (PCoA) was used to calculate Euclidean distances between taxonomic groups based on the pairwise Gower distances calculated from the functional traits of all taxonomic groups across the study interval. A convex hull was then constructed for each assemblage, and functional richness and functional dispersion were calculated. Functional richness quantifies the proportional occupation of all possible functional space, while functional dispersion is the centroid between taxonomic groups in functional space, calculated from a species richness weighting. Functional beta-diversity between assemblages was also calculated to evaluate the degree of functional nestedness and turnover between assemblages. These functional diversity metrics were then compared with taxonomic diversity, which is a count of the number of taxonomic groups in each time bin.