Consistent effects of pesticides on community structure and ecosystem function in freshwater systems

• Published in: Nature communications Vol. 11; no. 1; pp. 6333 - 9
• Main Authors: Rumschlag, Samantha L., Mahon, Michael B., Hoverman, Jason T., Raffel, Thomas R., Carrick, Hunter J., Hudson, Peter J., Rohr, Jason R.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.12.2020; Nature Publishing Group; Nature Portfolio
• Subjects: 631/158/2458; 631/158/2459; 631/158/670; 704/158/853; Abundance; Animals; Aquatic ecosystems; Biodiversity; Chemicals; Community composition; Community structure; Composition effects; Contaminants; Ecological effects; Ecological risk assessment; Ecosystem; Ecosystem assessment; Ecosystems; Environmental changes; Environmental risk; Fresh Water; Freshwater ecology; Freshwater ecosystems; Freshwater pollution; Functional groups; Herbicides; Humanities and Social Sciences; Insecta - drug effects; Insecticides; multidisciplinary; Multivariate Analysis; Pesticides; Pesticides - toxicity; Phytoplankton; Predatory Behavior - drug effects; Respiration; Risk assessment; Science; Science (multidisciplinary); Structure-function relationships; Toxicity; Zooplankton; Zooplankton - drug effects
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-20192-2

Predicting ecological effects of contaminants remains challenging because of the sheer number of chemicals and their ambiguous role in biodiversity-ecosystem function relationships. We evaluate responses of experimental pond ecosystems to standardized concentrations of 12 pesticides, nested in four pesticide classes and two pesticide types. We show consistent effects of herbicides and insecticides on ecosystem function, and slightly less consistent effects on community composition. Effects of pesticides on ecosystem function are mediated by alterations in the abundance and community composition of functional groups. Through bottom-up effects, herbicides reduce respiration and primary productivity by decreasing the abundance of phytoplankton. The effects of insecticides on respiration and primary productivity of phytoplankton are driven by top-down effects on zooplankton composition and abundance, but not richness. By demonstrating consistent effects of pesticides on communities and ecosystem functions and linking pesticide-induced changes in functional groups of organisms to ecosystem functions, the study suggests that ecological risk assessment of registered chemicals could be simplified to synthetic chemical classes or types and groups of organisms with similar functions and chemical toxicities. The effects of pesticides on individual species could propagate into additional community-wide and ecosystem-level effects. Here the authors use a mesocosm experiment to test how a diverse array of herbicides and insecticides disrupt aquatic community structure and ecosystem function.