title: Declines in insectivorous birds are associated with high neonicotinoid concentrations.
abstract: Recent studies have shown that neonicotinoid insecticides have adverse effects on non-target invertebrate species. Invertebrates constitute a substantial part of the diet of many bird species during the breeding season and are indispensable for raising offspring. We investigated the hypothesis that the most widely used neonicotinoid insecticide, imidacloprid, has a negative impact on insectivorous bird populations. Here we show that, in the Netherlands, local population trends were significantly more negative in areas with higher surface-water concentrations of imidacloprid. At imidacloprid concentrations of more than 20 nanograms per litre, bird populations tended to decline by 3.5 per cent on average annually. Additional analyses revealed that this spatial pattern of decline appeared only after the introduction of imidacloprid to the Netherlands, in the mid-1990s. We further show that the recent negative relationship remains after correcting for spatial differences in land-use changes that are known to affect bird populations in farmland. Our results suggest that the impact of neonicotinoids on the natural environment is even more substantial than has recently been reported and is reminiscent of the effects of persistent insecticides in the past. Future legislation should take into account the potential cascading effects of neonicotinoids on ecosystems.
authors.affiliation: 1] Radboud University, Institute of Water and Wetland Research, Departments of Experimental Plant Ecology & Animal Ecology and Ecophysiology, PO Box 9100 (Mail Box 31), 6500 GL Nijmegen, The Netherlands [2] Sovon, Dutch Centre for Field Ornithology, PO Box 6521, 6503 GA Nijmegen, The Netherlands.
authors.forename: Caspar A
authors.initials: CA
authors.lastname: Hallmann
authors.affiliation: 1] Sovon, Dutch Centre for Field Ornithology, PO Box 6521, 6503 GA Nijmegen, The Netherlands [2] Birdlife Netherlands, PO Box 925, 3700 AX Zeist, The Netherlands.
authors.forename: Ruud P B
authors.initials: RP
authors.lastname: Foppen
authors.affiliation: Sovon, Dutch Centre for Field Ornithology, PO Box 6521, 6503 GA Nijmegen, The Netherlands.
authors.forename: Chris A M
authors.initials: CA
authors.lastname: van Turnhout
authors.affiliation: Radboud University, Institute of Water and Wetland Research, Departments of Experimental Plant Ecology & Animal Ecology and Ecophysiology, PO Box 9100 (Mail Box 31), 6500 GL Nijmegen, The Netherlands.
authors.forename: Hans
authors.initials: H
authors.lastname: de Kroon
authors.affiliation: Radboud University, Institute of Water and Wetland Research, Departments of Experimental Plant Ecology & Animal Ecology and Ecophysiology, PO Box 9100 (Mail Box 31), 6500 GL Nijmegen, The Netherlands.
authors.forename: Eelke
authors.initials: E
authors.lastname: Jongejans
mesh_terms: D000383:Agriculture; D000818:Animals; D001717:Birds / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D004784:Environmental Monitoring; D020387:Food Chain; D007093:Imidazoles / Q000009:adverse effects*; D007313:Insecta; D007306:Insecticides / Q000009:adverse effects*; D000073943:Neonicotinoids; D009426:Netherlands; D009574:Nitro Compounds / Q000009:adverse effects*; D011157:Population Dynamics / Q000706:statistics & numerical data; D014873:Water Pollutants / Q000009:adverse effects
chemical_list: D007093:Imidazoles; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D014873:Water Pollutants; C082359:imidacloprid