Pesticides affect a diverse range of non-target species and may be linked to global biodiversity loss. The magnitude of this hazard remains only partially understood. We present a synthesis of pesticide (insecticide, herbicide and fungicide) impacts on multiple non-target organisms across trophic levels based on 20,212 effect sizes from 1,705 studies. For non-target plants, animals (invertebrate and vertebrates) and microorganisms (bacteria and fungi), we show negative responses of the growth, reproduction, behaviour and other physiological biomarkers within terrestrial and aquatic systems.

Pesticides formulated for specific taxa negatively affected non-target groups, e.g. insecticidal neonicotinoids affecting amphibians. Negative effects were more pronounced in temperate than tropical regions but were consistent between aquatic and terrestrial environments, even after correcting for field-realistic terrestrial and environmentally relevant exposure scenarios. Our results question the sustainability of current pesticide use and support the need for enhanced risk assessments to reduce risks to biodiversity and ecosystems.

Pesticides are used globally to support agricultural production and protect human and animal health in both domestic and commercial situations^{1,2,3,4,5,6,7,8}. At sufficient environmental concentrations, insecticide, fungicide and herbicide exposure can affect non-target organisms by disrupting their survival, growth, reproduction and behaviour (e.g. detection of stimuli), as well as effects on other metabolic and physiological processes (e.g. biomarkers of neural function or immunity, cellular respiration, photosynthesis)⁹. Some of the negative impacts of pesticides are known.

For example, fungicides may decrease the biomass of arbuscular mycorrhizal fungi, affecting their symbioses with higher plants¹⁰; herbicides may reduce plant pollen viability¹¹ and carbohydrate metabolism¹²; insecticides (targeting pest herbivores) may cause long-term declines in non-target insect pollinators associated with mass-flowering crops¹³. Such impacts appear widespread across taxa, with individual studies reporting effects on microorganisms¹⁴, plants¹⁵, invertebrates^5,16,17, amphibians¹⁸, birds^6,19 and mammals²⁰.

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Our analysis of field-realistic application rates confirmed the strong evidence for overall (insecticides, fungicides and herbicides together) significant negative effects on animal reproduction ….

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Overall, our synthesis comprehensively shows that insecticides, fungicides and herbicides have broad-scale detrimental effects on all groups of non-target organisms tested. Pesticides consistently decreased growth and reproduction across all taxonomic groups, while also eliciting behavioural responses in animals and perturbing multiple endpoints linked to metabolic or physiological status. Given the ubiquitous use of pesticides worldwide, estimated at about 4.1 million tons of active ingredient applied in 2015³⁹, these findings emphasize the potential for prevalent non-target impacts relating to widespread pesticide use. Specifically, these results suggest that pesticide use has the potential to result in wider perturbation of ecological communities and functions.

While we identified responses for individual compounds, it is likely that these effects may be exacerbated through additive or potentially synergistic effects where compounds are applied in combination or to areas with existing residues present⁴. We acknowledge that the reduction of pesticide use, while a superficially simple solution, is, in practice, likely to have widespread and significant consequences for food production and farmer livelihoods. Nevertheless, our findings highlight the need for widespread policy drivers to adopt solutions to reduce pesticide use and/or maximize the efficiency of inputs.

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