Effects of functional diversity and salinization on zooplankton productivity: an experimental approach

Quantifying the interactions between functional diversity and environmental change is important for understanding the effects of biodiversity on ecosystem processes. This study aims to evaluate zooplankton secondary production and biomass in an experiment with different levels of functional diversity and environmental stress in the form of increased salinity. It is expected that communities that are more functionally diverse will present higher secondary production and biomass, even under conditions of environmental stress. To test this hypothesis, a mesocosm experiment with two factors was performed: low and high diversity and with and without salt totaling four possible combinations of treatments over the duration of 4 weeks. The high functional diversity treatments showed higher zooplankton secondary production and biomass than those of the low diversity treatments, even under salt addition. The salinity decreased zooplankton production and functional diversity, but its effects were more pronounced in the low than in the high diversity communities. However, in the low diversity treatments the zooplankton biomass and production were maintained due to the dominance of species with certain traits. In summary, our study contributed to understanding the role of zooplankton functional diversity on ecosystem processes in the face of environmental changes promoted by increased salinity.