Combined effects of fungicides and temperature affect non-target aquatic fungal assemblages

The extensive use of pesticides in agriculture can lead to water contamination and have adverse effects on different groups of aquatic organisms, including those that are not targeted. In this context, organisms involved in the decomposition of organic matter in terrestrial and aquatic ecosystems can be affected by these chemicals. In addition, in a climate change scenario, changes in temperature can potentiate this effect, as this variable is a modulator of biological processes. The aim of this study was to investigate the effects of acute and chronic exposure of a commercial fungicide on aquatic decomposing fungi (non-target) at different temperatures (18 °C and 22 °C). For this, two experiments were carried out: (1) acute, in which the fungi were exposed to the fungicide during the stimulation of sporulation (48 h) at both temperatures, and (2) chronic, in which the fungi were exposed to the fungicide during the period of substrate colonization (25 days) at both temperatures. The effective concentration to inhibit 50% (EC50) of sporulation rates at 22 °C was lower than at 18 °C. For both situations, fungal activity was inhibited with increasing fungicide concentrations. It was also verified that the temperature had an important role in the fungal response to stressors, since an increase in temperature potentiated the fungicide effect in the acute and chronic experiments. The results show that excessive use of fungicides, associated with an increase in temperature, can cause changes in the fungal community and their ability to reproduce.