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Ecological impacts of genetically engineered crops: a case study of the Farm Scale Evaluations

Ecological impacts of genetically engineered crops: a case study of the Farm Scale Evaluations. L. LaReesa Wolfenbarger University of Nebraska. GEO Environmental Risks and Benefits. Risks of invasiveness Non-target organism impacts New viral diseases Reduced pesticide environmental impact

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Ecological impacts of genetically engineered crops: a case study of the Farm Scale Evaluations

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  1. Ecological impacts of genetically engineered crops: a case study of the Farm Scale Evaluations L. LaReesa Wolfenbarger University of Nebraska

  2. GEO Environmental Risks and Benefits • Risks of invasiveness • Non-target organism impacts • New viral diseases • Reduced pesticide environmental impact • Reduced rate of land conversion • Soil conservation • Phytoremediation Source: Wolfenbarger & Phifer (2000) Science

  3. Pathways to invasiveness Introduction of plant Pollen flow Hybrid formation Survival Hybrid survival Reproduction Hybrid reproduction Self-sustaining Gene introgression Spread and persistence

  4. Presence of transgenic crop or its transgene plant above ground roots decomposing tissue pollen drift gene flow to wild relatives in natural ecosystem Pathways by which environmental impacts could occur

  5. Changes in agricultural practices associated with adoption of a transgenic crop Pesticide use patterns Amount of agricultural land Tillage practices Crop diversity/rotation Pathways by which ecosystem effects could occur

  6. Non-target data considered in latest EPA risk assessment for Bt crops* OVERALL Very limited evidence for toxic effects* • Larval and adult honeybee • Green lacewing* • Ladybird beetles • Parasitic Hymenoptera • Monarch butterfly* • Avian oral toxicity • Static renewal acute toxicity, Daphnia • Corn as food for farmed fish • Collembola • Earthworms *Standard studies based on EPA Subdivision M and/or OPPTS 885 Guidelines

  7. Monarch butterflyRisk assessment over a large geographic scale

  8. Farm Scale Evaluations • Test hypothesis that biodiversity will be the same in fields managed with GM crops compared to conventional counterparts

  9. Farm Scale Evaluations:Why? • By 1998 GE Herbicide tolerant crops have cleared most hurdles for commercialization • BUT, concerns that GE Herbicide tolerant crops will reduce plant and invertebrate populations on which farmland wildlife depend

  10. Farming in the UK • Arable and pastoral farming • 75% of surface area • Land use continuous since 700 BC

  11. Farmland is the environment • Average farm size is 50 ha • Lots of edge habitat • Wildlife depends on fields and margins

  12. Status of birds in the UK

  13. Farm Scale Evaluations:Why? • Concerns that GE Herbicide tolerant crops will reduce plant and invertebrate populations on which farmland wildlife depend

  14. Design of the FSE • Fields planted 1/2 GE, 1/2 Conventional • Approx 60 fields per crop • Four GE herbicide tolerant crops: beets, maize, spring oilseed rape and winter rapeseed

  15. Sites distributed over the UK

  16. Design of the FSE • Fields planted 1/2 GE, 1/2 Conventional • Approx 60 fields per crop • Four GE herbicide tolerant crops: beets, maize, spring oilseed rape (canola) and winter rapeseed • Measure biodiversity within fields and at margins • Biodiversity: weeds, seeds and inverts

  17. Habitats sampled

  18. Why not measure birds? • Plants and inverts respond directly to herbicide management • Conclusion of no effect more robust • Model effect on birds

  19. Herbicide practices during FSE GE crop Fewer applications, later timing, weed cover variability

  20. Herbicide practices: Maize GE crop More weed cover in GE half of field

  21. Herbicide practices: Oilseed rape GE cropping: later, fewer More weed cover with conventional cropping

  22. Results: 8 papers, >100 Tables and figures

  23. Andow’s cheat sheet for results

  24. What do we do with this?

  25. Complications to maize interpretations? • Atrazine banned in 2003

  26. Largest differences due to crop and season

  27. Status of birds in the UK

  28. How was information from FSE used?

  29. Policy results • Advisory committee recommends ban on GE HT beets and oilseed and approval of GE HT maize

  30. Recommendations to parliament • oppose EU approval for the commercial cultivation of the GM beet and oilseed rape as grown in the FSE trials • only allow the commercial cultivation of the GM maize in the FSE trials if restrictions are imposed on its EU marketing consent to limit herbicide use March 2004

  31. March 2005 • BayerCropScience withdraws its plans to cultivate its approved GE corn • “…too many demands”

  32. November 2005 • No GE crops grown in the UK • None expected before 2008 • Approval for use of GE crops in feed is occurring

  33. And, the latest…. Swiss citizens are not prepared to sell their souls and convictions to satisfy their consumer tastes. Le Matin on approval of a five-year ban on GM foods, 28 November 2005

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