Climate-change influences on the response of macroinvertebrate communities to pesticide contamination in the Sacramento River, California watershed

• Published in: The Science of the total environment 2017-03, Vol.581-582, p.741-749
• Main Authors: Chiu, Ming-Chih, Hunt, Lisa, Resh, Vincent H.
• Format: Article
• Language: English
• Subjects: Agriculture; Animals; Aquatic ecotoxicity; Benthic macroinvertebrates; California; Climate Change; Environmental Monitoring; Invertebrates; Pesticides - analysis; Precipitation; Rivers; Sediment; Warming; Water Pollutants, Chemical - analysis
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2017.01.002

Limited studies have addressed how future climate-change scenarios may alter the effects of pesticides on biotic assemblages or the effects of exposures to repeated pulses of pesticide mixtures. We used reported pesticide-use data as input to a hydrological fate and transport model (Soil and Water Assessment Tool) under multiple climate-change scenarios to simulate spatiotemporal dynamics of pesticides mixtures in streams on a daily time-step in the Sacramento River watershed of California. We predicted that there will be increased pesticide application with warming across the watershed, especially in upstream areas. Using a statistical model describing the relationship between macroinvertebrate communities and pesticide dynamics, we found that compared to the baseline period of 1970–1999: (1) most climate-change scenarios predicted increased rainfall and warming across the watershed during 2070–2099; and (2) increasing pesticide contamination and increased impact on macroinvertebrates will likely occur in most areas of the watershed by 2070–2099; and (3) lower increases in effects of pesticides on macroinvertebrates were predicted for the downstream areas with intensive agriculture compared to some upstream areas with less-intensive agriculture. Future efforts on practical adaptation and mitigation strategies can be improved by awareness of altered threats of pesticide mixtures under future climate-change conditions. [Display omitted] •There will likely be increased pesticide application with increasing temperature.•Increased ecological impacts of pesticides were predicted in most of the watershed.•More increases in impacts were predicted in areas with less intensive agriculture.