Functional Diversity has Positive Impacts on Dietary Nutrients Supplied by Inland Fisheries

Background/Question/Methods

Species, through their myriad traits, influence the ability of ecosystems to simultaneously provide multiple functions and services. However, it is unclear how functional diversity, or the variation in traits among species in a community, sustains multiple ecosystem services. Freshwater fisheries provide millions of people across the world with their primary source of essential nutrients such as protein, omega-3 fatty acids, iron and zinc, but are increasingly threatened by hydropower development, overharvesting and climate change. Here we analyze how the loss of fish functional diversity affects the simultaneous provisioning of six essential dietary nutrients using trait-based modeling and detailed household surveys of fish catches from the Amazon and Tonle Sap ecosystems, where inland fish are a staple of people’s diets.

Results/Conclusions

We find that the minimum portion size needed to sustain adequate human nutrition is lower in fish communities with higher functional diversity. Further, more functionally diverse communities can simultaneously meet human dietary requirements for a greater variety of nutrients. This beneficial effect of functional diversity on multiple ecosystem services increases when considering more nutrients. Because no fish species is high in content of all nutrients, our findings imply that conserving freshwater biodiversity can maximize options for sustaining nutritional security for over 150 million people dependent on freshwater fisheries worldwide.