Authors

Discussion

Traditionally, Taxonomic Diversity (TD) is used to measure diversity, mainly as richness or abundance of species present in a given sample. The greatest limitation of TD metrics is that they consider species as equivalent entities, with no consideration of their phylogenetic relationships and functional role in the community. To tackle this issue, it has been proposed to incorporate phylogenetic and functional distances between species when measuring diversity. Thus, Functional Diversity (FD) is based on estimating  diversity in a community using distances between functional traits of species (i.e. phenotypic traits that impact fitness of individuals via their effects on growth, reproduction and survival). It has been shown that studies of FD can unveil the processes that determine species composition in ecosystems and the responses of organisms to different factors. However, despite the promise of FD approaches and the ubiquity of parasites in ecosystems, very few studies have concentrated in communities of these organisms. We aim to develop a practical framework of functional traits of aquatic helminth parasites ready for application in FD studies. Furthermore, to show the usefulness of our list of functional traits, we calculated TD and FD of the helminth parasite fauna (Monogeneans, Trematodes, Nematodes and Acanthocephalans) of the flathead grey mullet (Mugil cephalus) from three habitats: one marine and two brackish. For TD and FD analyses, we measured diversity at alpha (individual host) and beta (locality) levels of organisation using the Rao quadratic entropy index. In our case study, we determined the assembly of the parasite species at host and locality levels. Moreover, we define the heterogeneity of the community composition in terms of both parasite species and functional traits. We expect that our framework of functional traits would inspire future FD analyses of parasite communities.