Conclusions of the Worldwide Integrated Assessment on the risks of neonicotinoids and fipronil to biodiversity and ecosystem functioning

Large scale and partly prophylactic use of neonicotinoids and fipronil has raised concerns about the risks they pose to biodiversity, ecosystem functioning and ecosystem services. The Worldwide Integrated Assessment (WIA) presented in this special issue is the first attempt to synthesize the state of knowledge on these risks and covers over 800 peer-reviewed publications. Here, we present the main findings and discus key knowledge gaps. Our main conclusions are: 1) trends in use and application of systemic insecticides notably the neonicotinoid compounds show a rapid increase over the past decade in several countries worldwide; 2) the combination of environmental persistence (over months or years) and high water solubility has led to large scale contamination of soils, ground and surface water and plant tissues from both treated crops and non-treated plants. In some cases, the most persistent neonicotinoids can build-up over time in soils, and possibly also in tissues of woody plants, following repeated applications over multiple years; 3) Multiple routes exist for short and long term exposure of non-target species through contamination of air, soil, water and plants. Based on the patterns of use and the persistence profile, terrestrial and aquatic organisms are often repeatedly or chronically exposed to varying environmental concentrations of these compounds; 4) The existing literature from laboratory and field test systems demonstrates that the current authorized uses of neonicotinoids and fipronil (i.e. following label rates and applying compounds as intended) have resulted in levels of environmental contamination that frequently exceed thresholds known to cause adverse effects for a wide range of non-target organisms, particularly insects, and are thus likely to have biological and ecological impacts at the ecosystem level. Although pesticides have been widely used for decades, the environmental impacts of the persistent, systemic, and mobile compounds we focus on in this review seem unprecedented. The data reviewed here strongly indicate that the present scale of use of neonicotinoid and fipronil insecticides is not a sustainable pest management strategy. In fact, the current practice poses serious risks of harm to numerous organisms and subsequently to the ecological functions they perform. In the agricultural setting, where the majority of these compounds are used, it is becoming increasingly clear that neonicotinoids and fipronil are incompatible with the mindset which led to the principles of integrated pest management (IPM), given that these systemic pesticides are routinely applied often in the absence of any pest outbreak or economically measurable threat. Effective management strategies for controlling target pests should consider alternative organic or IPM approaches. These compounds possess physical and (bio)chemical properties that carry a high risk for effects beyond the intended target pest, crop and field. Therefore, the authors recommend that policy makers recognize this breadth of risks to biodiversity and consider applying the precautionary principle to further tighten regulations on neonicotinoids and fipronil.