Toxicant effects on trophic interactions of fluvial invertebrates

MUÑOZ ISABEL; DE CASTRO CATALA NURIA; HERBERA XAVIER; MENENDEZ MARGARITA; MOR J.R; SOLIS MARINA; SABATER S

Congreso; XX Congress of the Iberian Association of Limnology (AIL-2020) III Iberoamerican Congress of Limnology (CIL-2020); 2020

Chemical pollution has been identified as one of the planetary boundaries for which continued impacts could erode the resilience of ecosystems. Sources of chemical pollution in fluvial systems lives rise to a mixture of toxicants that makes it difficult to attribute effects to any particular toxicant. In addition, rivers are suffering other natural and anthropogenic stressors affecting biologicalcommunities and ecosystem functioning, which can ultimately affect goods and services derived from them.The effects of toxicants can be measured at different level (e.g. individual, population, community level) but the assessment of combined effects of stressors and implication for ecosystem functioning are still unclear. Trophic interactions determine energy transfer in the system. The analysis of the effects of pollution on resource-consumer response variables contributes to better elucidate effects at ecosystem level. We present several experiments analyzing the direct and indirect effects of different toxicant compounds, acting alone or in combination, on feeding rates of different freshwater key species. Fungicides and antidepressants reduced the leaf litter consumption by shredders and changed how they researched the food. Herbicide and fungicide effects were tested on shredders and grazers detecting effects on leaf litter and biofilm consumption likely relevant elsewhere in the food chain and through the entire ecosystem. Relevant effects to the trophic network were also observed in a field experiment. Wastewater pollution (mainly nutrients and pharmaceuticals) in Mediterranean streams reduced energy efficiency transfer along the food web reducing predator richness and food web resilience.