Canadian Forest Service Publications
Risks of large-scale use of systemic insecticides to ecosystem functioning and services. 2014. Chagnon, M.; Kreutzweiser, D.; Mitchell, E.A.D.; Morrissey, C.A.; Noome, D.A.; Van der Sluijs, J.P. Environmental Science and Pollution Research DOI 22:119-134.
Issued by: Great Lakes Forestry Centre
Catalog ID: 35638
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Large-scale use of the persistent and potent neonicotinoid and fipronil insecticides has raised concerns about risks to ecosystem functions provided by a wide range of species and environments affected by these insecticides. The concept of ecosystem services is widely used in decision making in the context of valuing the service potentials, benefits, and use values that well-functioning ecosystems provide to humans and the biosphere and, as an endpoint (value to be protected), in ecological risk assessment of chemicals. Neonicotinoid insecticides are frequently detected in soil and water and are also found in air, as dust particles during sowing of crops and aerosols during spraying. These environmental media provide essential resources to support biodiversity, but are known to be threatened by long-term or repeated contamination by neonicotinoids and fipronil. We review the state of knowledge regarding the potential impacts of these insecticides on ecosystem functioning and services provided by terrestrial and aquatic ecosystems including soil and freshwater functions, fisheries, biological pest control, and pollination services. Empirical studies examining the specific impacts of neonicotinoids and fipronil to ecosystem services have focused largely on the negative impacts to beneficial insect species (honeybees) and the impact on pollination service of food crops. However, here we document broader evidence of the effects on ecosystem functions regulating soil and water quality, pest control, pollination, ecosystem resilience, and community diversity. In particular, microbes, invertebrates, and fish play critical roles as decomposers, pollinators, consumers, and predators, which collectively maintain healthy communities and ecosystem integrity. Several examples in this review demonstrate evidence of the negative impacts of systemic insecticides on decomposition, nutrient cycling, soil respiration, and invertebrate populations valued by humans. Invertebrates, particularly earthworms that are important for soil processes, wild and domestic insect pollinators which are important for plant and crop production, and several freshwater taxa which are involved in aquatic nutrient cycling, were all found to be highly susceptible to lethal and sublethal effects of neonicotinoids and/or fipronil at environmentally relevant concentrations. By contrast, most microbes and fish do not appear to be as sensitive under normal exposure scenarios, though the effects on fish may be important in certain realms such as combined fish-rice farming systems and through food chain effects. We highlight the economic and cultural concerns around agriculture and aquaculture production and the role these insecticides may have in threatening food security. Overall, we recommend improved sustainable agricultural practices that restrict systemic insecticide use to maintain and support several ecosystem services that humans fundamentally depend on.
Plain Language Summary
This paper is part of the Worldwide Integrated Assessment (WIA) of Systemic Pesticides series of papers in Environmental Science and Pollution Research. The WIA is a comprehensive literature review and synthesis on environmental risks associated with the use of the systemic insecticides, neonicotinoids and fipronil. David Kreutzweiser is a research scientist at NRCan/CFS and is a participant and author in the WIA. This paper examines the risks of adverse effects of these systemic insecticides on ecosystem function and services. The synthesis shows that because neonicotinoids in particular are widely used, highly toxic to a broad range of non-target organisms, and often persistent, they cause negative effects on critical ecosystem functions. The most extensively studied example of this is the adverse effects of neonicotinoids on honeybees and the impacts on pollination services to food crops. However, the synthesis shows emerging evidence of impacts on a wide range of ecosystem functions regulating soil and water quality, natural pest control, and biodiversity. The NRCan, CFS research into effects of imidacloprid in leaf material from treated trees on nutrient cycling processes in soils and water bodies is featured prominently. Policy implications to the NRCan are minimal. There is one neonicotinoid, imidacloprid, registered for forestry in Canada, but the use of imidacloprid in forest pest control is currently very limited and therefore the environmental exposure and risk from the forestry use of this neonicotinoid in Canada is negligible.