Diversidade funcional do zooplâncton em cinco reservatórios de Poços de Caldas MG, Brasil e taxas de filtração de duas espécies de Cladocera

Abstract

Zooplankton is responsible for much of the energy exchange in the water column and the herbivory practiced by these organisms plays an important role in the cycling of nutrients and control of phytoplanktonic density, mainly by filtering organisms. The particle capture efficiency, or filtration rate of the organism, can be used as a functional trait that allows understanding of how the species behaves in relation to the capture and concentration of food in the medium. Functional diversity has been used to try to explain how organisms influence the functioning of the ecosystem and how they are influenced by it, through the analysis of the functional traits present in the community. This work aimed to calculate the filtration rate of two species of Cladocera: Diaphanosoma spinulosum and Sarsilatona serricauda in different concentrations of Raphidocelis subcapitata and also the diversity, abundance and richness of zooplanktonic species, their functional groups and the functional indexes of five reservoirs of the Poços de Caldas region, which are used for different purposes and provide ecosystem services of great commercial and biological importance to the population, but are directly influenced by industrial processes present in the city, mainly related to mining. The results demonstrate that D. spinulosum and S. serricauda have their feeding behavior influenced by the concentration and variety of suspended food particles, being impaired in high concentrations. The zooplankton community was mostly represented by species of the Phylum Rotifera in all reservoirs. There was a separation of six functional groups, mainly from the eating habit, trophic group and habitat. These bodies of water had physical and chemical conditions that benefited the functional group formed by filters and suction feeders. The functional diversity indices demonstrated that there are anthropic pressures influencing the functional composition of the reservoirs, decreasing long-term productivity. These changes can result in a decrease in ecosystem services provided by these reservoirs to the municipality, with economic and environmental losses.