In the marine benthos, both bioturbation intensity and benthic nutrient fluxes increase as macrofauna species richness increases, and this is underpinned by functional trait diversity. Functional traits are morphological or physiological features of individuals that affect ecosystem properties, and can be used to assign organisms to functional groups; sets of species that have a similar effect on ecosystem processes, and so are functionally equivalent. Therefore, in an ecosystem where two species from the same functional group coexist, the presence of one species would theoretically compensate for the potential loss of the other. Thus this loss would have negligible consequences for ecosystem processes and functioning, and hence the functional
