The relationship between macrofauna diversity, functional diversity, and secondary production

The relationship between functional diversity and secondary production are known to influence ecosystem stability and can be used to measure the functioning of an ecosystem. Functional diversity is a component of biodiversity that classifies organisms by what they do (i.e., functional types) in a community or ecosystem, or more specifically by how certain traits effect the functioning of the environment. Secondary production occurs when biomass is generated by heterotrophic organisms when they consume organic material or primary producers. The research objective is to determine the relationship between secondary production and the connection between functional diversity and species diversity in estuary systems. The goal is to test the hypothesis that there is a positive relationship between functional diversity and secondary benthic productivity among bays within four mid-coastal Texas estuaries: Nueces Estuary, Laguna Madre Estuary, Guadalupe Estuary, and Lavaca-Colorado Estuary. Freshwater inflow differences among these estuaries can affect biodiversity, productivity, and habitat. Thus, changes of freshwater inflow could lead to variability in functional diversity and secondary productivity. Functional diversity was calculated based on seven classifiers: feeding strategy, habitat, mobility, lifespan, reproduction, sediment depth, and body size. There was a positive correlation between benthic production and diversity for species richness, species diversity, and species evenness and secondary production. Most functional diversity indices did not show any significance; however, functional dispersion was shown to explain >77% of variation for secondary production. Apart from functional originality, there did not appear to be a significant relationship between indicators of freshwater inflow influence (i.e., increase in nutrients and decrease in salinity) and the diversity metrics. In general, the response in primary and secondary bays is different, except for the lower part of San Antonio Bay. Overall, classical measures of macrofauna species diversity have a strong relationship with secondary production, while functional diversity does not appear to have any relationship. Thus, for Texas estuaries, it appears that functional diversity metrics do not explain or drive benthic ecosystem processes.