Multiple stressors in Mediterranean coastal wetland ecosystems: Influence of salinity and an insecticide on zooplankton communities under different temperature conditions

Temperature increase, salinity intrusion and pesticide pollution have been suggested to be among the main stressors affecting the biodiversity of coastal wetland ecosystems. Here we assessed the single and combined effects of these stressors on zooplankton communities collected from a Mediterranean coastal lagoon. An indoor microcosm experiment was designed with temperature variation (20 degrees C and 30 degrees C), salinity (no addition, 2.5 g/L NaCl) and the insecticide chlorpyrifos (no addition, 1 mu g/L) as treatments. The impact of these stressors was evaluated on water quality variables and on the zooplankton comunity (structure, diversity, abundance and taxa responses) for 28 days. This study shows that temperature is the main driver for zooplankton community change, followed by salinity and chlorpyrifos. The three stressors contributed to a decrease on zooplankton diversity. The increase of temperature contributed to an increase of zooplankton abundance. Salinity generally affected Cladocera, which resulted in a Copepoda increase at 20 degrees C, and a reduction in the abundance of all major zooplankton groups at 30 degrees C. The insecticide chlorpyrifos affected primarily Cladocera, altough the magnitude and duration of the direct and indirect effects caused by the insecticide substantially differed between the two temperature scenarios. Chlorpyrifos and salinity resulted in antagonistic effects on sensitive taxa (Cladocera) at 20 degrees C and 30 degrees C. This study shows that temperature can influence the direct and indirect effects of salinity and pesticides on zooplankton communities in Mediterranean coastal wetlands, and highlights vulnerable taxa and ecological responses that are expected to dominate under future global change scenarios. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

This study highlights that temperature is the main driver for changes in zooplankton communities, followed by salinity and chlorpyrifos. The three stressors contributed to a decrease in zooplankton diversity, with an increase in zooplankton abundance driven by higher temperatures. Salinity affected Cladocera and resulted in Copepoda increase at lower temperature, while reducing the abundance of all major zooplankton groups at higher temperature. Chlorpyrifos primarily affected Cladocera, with antagonistic effects on sensitive taxa in combination with salinity at both temperature scenarios.