Environmental Impact of Genetically Modified Organisms (GMOs)

Abstract

The intensification of agriculture has provided cheaper more plentiful food, but has also caused declines in farmland wildlife. The introduction of genetically modified (GM) crops may exacerbate this, or offer new ways of mitigating anthropogenic impacts. The potential consequences of the introduction of GM crops have been studied for over a decade, since commercialization. Although the specific issues depend on the crop and transgenes involved, one common theme that emerges is that the biggest effects will arise from the way in which the GM crop will be managed. Herbicide‐tolerant GM crops may allow better weed control, and this is a risk to biodiversity that should be mitigated. However, even herbicide‐tolerant crops have some environmental benefits through reduced production and application of herbicides. Insect and disease‐resistant crops will have fewer impacts on nontarget organisms than conventional crops and their management, and so may offer direct environmental benefits.

Key concepts

  • Farmland biodiversity has been enhanced and maintained by agricultural land management over hundreds of years. Changes in the intensity of farming since the 1970s have caused its decline, and any future change may exacerbate or ameliorate this impact.

  • Global warming potential (GWP) is the potential of a gas produced by a product or a process to contribute to global warming. It is measured over a specific time period, and on a scale relative to carbon dioxide. Different agricultural practices will have different GWP.

  • Life cycle assessment is defined as an objective process to evaluate the environmental burdens associated with a product or a process by identifying energy and materials used and wastes released to the environment.

  • Meta‐analysis involves retrieving and combining data from a number of studies to obtain a quantitative estimate of the overall effect which can be statistically analysed.

  • Refuge strategy is the strategy employed to delay or prevent the build up of pests resistant to the GM crop. It involves a ‘refuge’ of approximately 20% of the crop in which susceptible individuals may survive, in contrast to the 80% of the crop in which the majority of the pest individuals fail to reach maturity. Any rare resistant individuals that do survive are then likely to mate with a susceptible individual and produce susceptible offspring.

  • Natural enemy release posits that natural enemies limit the growth or survival of plants. Resistance to these natural enemies could release a plant genotype from natural enemy regulation and lead to invasiveness.

  • Comparative sustainability assessment is a matrix‐based approach to assess comparative sustainability, benefits and risks of the introduction of any novel agricultural products or practices. The purpose is to develop a more objective and comprehensive approach towards agricultural and rural policy.

Keywords: GMOs; environmental impact; risk assessment; farmland biodiversity; pesticides

Figure 1.

The mean number of applications of herbicides (±SE) applied during the Farm Scale Evaluations. Data taken from Table 2 of Champion et al.. Figures include pre‐drilling applications and, for spring oilseed rape, desiccants.

Figure 2.

Star plots comparing biodiversity indicators across conventional and GMHT crops. For each indicator, the length of the star corresponds to the value relative to the maximum value found for that indicator in any of the six combinations of crop and treatment (e.g. the maximum values for bees and butterflies were found in conventional spring oilseed rape). The key shows which section of the star diagram represents which indicator. Reproduced from Firbank et al..www.defra.gov.uk/environment/gm/fse/results/fse‐commentary.pdf. With permission of the Department of the Environment, Food and Rural Affairs.

Figure 3.

In bioremediation, plants and bacteria may work in consortia to degrade xenobiotics. Plants may take up the by‐products of metabolism of bacteria, they may also selectively support indigenous degrading bacteria in their rhizosphere. Reproduced from Macek et al.. With permission from Elsevier.

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References

ACRE (2004) Advice on the Implications of the Farm‐scale Evaluations of Genetically Modified Herbicide‐tolerant Crops, p. 17. London: Department for the Environment, Food and Rural Affairs.

ACRE (2007) Managing the Footprint of Agriculture: Towards a Comparative Assessment of Risks and Benefits for Novel Agricultural Systems, p. 90. London: Department for the Environment, Food and Rural Affairs.

Bennett R, Phipps R, Strange A and Grey P (2004) Environmental and human health impacts of growing genetically modified herbicide‐tolerant sugar beet: a life‐cycle assessment. Plant Biotechnology Journal 2(4): 273–278.

Benton TG, Bryant DM, Cole L and Crick HQP (2002) Linking agricultural practice to insect and bird populations: a historical study over three decades. Journal of Applied Ecology 39(4): 673–687.

Champion GT, May MJ, Bennett S et al. (2003) Crop management and agronomic context of the farm scale evaluations of genetically modified herbicide tolerant crops. Philosophical Transactions of the Royal Society of London Series B 358: 1801–1818.

Desjardins RL, Sivakumar MVK and de Kimpe C (2007) The contribution of agriculture to the state of climate: workshop summary and recommendations. Agricultural and Forest Meteorology 142(2–4): 314–324.

Faria CA, Wackers FL, Pritchard J, Barrett DA and Turlings TCJ (2007) High susceptibility of Bt maize to aphids enhances the performance of parasitoids of lepidopteran pests. PLoS ONE 2(7): e600.

Firbank LG, Heard MS, Woiwod IP et al. (2003a) An introduction to the farm‐scale evaluations of genetically modified herbicide‐tolerant crops. Journal of Applied Ecology 40(1): 2–16.

Firbank LG, Perry JN, Squire GR et al. (2003b) The implications of spring‐sown genetically modified herbicide‐tolerant crops for farmland biodiversity. www.defra.gov.uk/environment/gm/fse/results/fse‐commentary.pdf.

Freckleton RP, Stephens PA, Sutherland WJ and Watkinson AR (2004) Amelioration of biodiversity impacts of genetically modified crops: predicting transient versus long‐term effects. Proceedings of the Royal Society of London Series B 271: 325–331.

Fuchs M, Gal‐On A, Raccah B and Gonsalves D (1999) Epidemiology of an aphid nontransmissible potyvirus in fields of nontransgenic and coat protein transgenic squash. Transgenic Research 8(6): 429–439.

Fuchs M and Gonsalves D (2007) Safety of virus‐resistant transgenic plants two decades after their introduction: lessons from realistic field risk assessment studies. Annual Review of Phytopathology 45: 173–202.

Godfree RC, Thrall PH and Young AG (2007) Enemy release after introduction of disease‐resistant genotypes into plant‐pathogen systems. Proceedings of the National Academy of Sciences of the USA 104(8): 2756–2760.

Gould F (1998) Sustainability of transgenic insecticidal cultivars: integrating pest genetics and ecology. Annual Review of Entomology 43: 701–726.

Hails RS (2002) Assessing the risks associated with new agricultural practices. Nature 418: 685–688.

Hails RS and Gray AJ (2004) Developing protocols for risk assessment. In: van Emden HF, Gray AJ (eds), GM Crops – Ecological Dimensions. Aspects of Applied Biology, vol. 74, pp. 169–182. Warwick: Wellesbourne.

Hails RS and Kindelerer J (2003) The GM public debate: context and communication strategies. Nature Reviews. Genetics 4: 819–825.

Heard MS, Hawes C, Champion GT et al. (2003a) Weeds in fields with contrasting conventional and genetically modified herbicide‐tolerant crops. I. Effects on abundance and diversity. Philosophical Transactions of the Royal Society of London Series B 358: 1819–1832.

Heard MS, Hawes C, Champion GT et al. (2003b) Weeds in fields with contrasting conventional and genetically modified herbicide‐tolerant crops. II. Effects on individual species. Philosophical Transactions of the Royal Society of London Series B 358: 1833–1846.

James C (2008) Global status of commercialized biotech/GM crops. ISAA Brief No. 39. ISAA: Ithaca, NY.

Kling J (1996) Agricultural ecology – could transgenic supercrops one day breed superweeds? Science 274(5285): 180–181.

Liu B, Hibbard JK, Urwin PE and Atkinson HJ (2005) The production of synthetic chemodisruptive peptides in planta disrupts the establishment of cyst nematodes. Plant Biotechnology Journal 3(5): 487–496.

Lovei GL and Arpaia S (2005) The impact of transgenic plants on natural enemies: a critical review of laboratory studies. Entomologia Experimentalis Et Applicata 114(1): 1–14.

Macek T, Kotrba P, Svatos A et al. (2008) Novel roles for genetically modified plants in environmental protection. Trends in Biotechnology 26(3): 146–152.

Marvier M, McCreedy C, Regetz J and Kareiva P (2007) A meta‐analysis of effects of Bt cotton and maize on nontarget invertebrates. Science 316(5830): 1475–1477.

May MJ, Champion GT, Dewar AM, Qi AM and Pidgeon JD (2005) Management of genetically modified herbicide‐tolerant sugar beet for spring and autumn environmental benefit. Proceedings of the Royal Society of London Series B. Biological Sciences 272(1559): 111–119.

Obrist LB, Dutton A, Romeis J and Bigler F (2006) Biological activity of Cry1Ab toxin expressed by Bt maize following ingestion by herbivorous arthropods and exposure of the predator Chrysoperla carnea. BioControl 51(1): 31–48.

Pallett DW, Thurston MI, Cortina‐Borja M et al. (2002) The incidence of viruses in wild Brassica rapa ssp. sylvestris in southern England. Annals of Applied Biology 141(2): 163–170.

Pidgeon JD, May MJ, Perry JN and Poppy GM (2007) Mitigation of indirect environmental effects of GM crops. Proceedings of the Royal Society of London Series B. Biological Sciences 274(1617): 1475–1479.

Raybould AF, Alexander MJ, Mitchell E et al. (2003) The ecology of turnip mosaic virus in populations of wild Brassica species. In: Hails RS, Godfray HCJ and Beringer J (eds) Genes in the Environment, pp. 226–244. Oxford: Blackwells.

Raybould AF, Maskell LC, Edwards ML, Cooper JI and Gray AJ (1999) The prevalence and spatial distribution of viruses in natural populations of Brassica oleracea. New Phytologist 141(2): 265–275.

Romeis J, Meissle M and Bigler F (2006) Transgenic crops expressing Bacillus thuringiensis toxins and biological control. Nature Biotechnology 24(1): 63–71.

Ruiz ON and Daniell H (2009) Genetic engineering to enhance mercury phytoremediation. Current Opinion in Biotechnology 20: 1–7.

Rylott EL and Bruce NC (2009) Plants disarm soil: engineering plants for the phytoremediation of explosives. Trends in Biotechnology 27(2): 73–81.

SETAC (1991) A Technical Framework for Life‐cycle Assessments. Washington DC: Society of Environmental Toxicology and Chemistry.

Strange A, Park J, Bennett R and Phipps R (2008) The use of life‐cycle assessment to evaluate the environmental impacts of growing genetically modified, nitrogen use‐efficient canola. Plant Biotechnology Journal 6(4): 337–345.

Tabashnik BE, Gassmann AJ, Crowder DW and Carriere Y (2008) Insect resistance to Bt crops: evidence versus theory. Nature Biotechnology 26(2): 199–202.

Thurston MI, Pallett DW, Cortina‐Borja M et al. (2001) The incidence of viruses in wild Brassica nigra in Dorset (UK). Annals of Applied Biology 139(3): 277–284.

Turturo C, Friscina A, Gaubert S et al. (2008) Evaluation of potential risks associated with recombination in transgenic plants expressing viral sequences. Journal of General Virology 89: 327–335.

Vojtech E, Meissle M and Poppy GM (2005) Effects of Bt maize on the herbivore Spodoptera littoralis (Lepidoptera: Noctuidae) and the parasitoid Cotesta marginiventris (Hymenoptera: Braconidae). Transgenic Research 14(2): 133–144.

Wolfenbarger LL, Naranjo SE, Lundgren JG, Bitzer RJ and Watrud LS (2008) Bt crop effects on functional guilds of non‐target arthropods: a meta‐analysis. PLoS ONE 3(5): e2118.

Further Reading

Ammann K (2008) Integrated farming: why organic farmers should use transgenic crops. New Biotechnology 25(2/3): 101–107.

Devos Y, Demont M, Dillen K et al. (2009) Coexistence of genetically modified (GM) and non‐GM crops in the European Union. A review. Agronomy for Sustainable Development 29(1): 11–30.

GM Science Review Panel (2003) GM science review: first report. London, p. 296. www.gmsciencedebate.org.uk/report/pdf/gmsci‐report1‐full.pdf.

Hails RS (2000) Genetically modified plants – the debate continues. Trends in Ecology & Evolution 15(1): 14–18.

Hails RS and Morley K (2005) Genes invading new populations: a risk assessment perspective. Trends in Ecology & Evolution 20(5): 245–252.

Lilley AK, Bailey MJ, Cartwright C, Turner SL and Hirsch PR (2006) Life in earth: the impact of GM plants on soil ecology? Trends in Biotechnology 24(1): 9–14.

Phipps RH and Park JR (2002) Environmental benefits of genetically modified crops: global and European perspectives on their ability to reduce pesticide use. Journal of Animal and Feed Sciences 11: 1–18.

The Royal Society (2003) GM crops, modern agriculture and the environment. London, p. 17. royalsociety.org/displaypagedoc.asp?id=11321.

Sanvido O, Romeis J and Bigler F (2007) Ecological impacts of genetically modified crops: ten years of field research and commercial cultivation. Green Gene Technology: Research in an Area of Social Conflict 107: 235–278. Springer, Berlin.

Woiwod IP and Schuler TH (2007) Genetically modified crops and insect conservation. In: Stewart AJA, New TR and Lewis OT (eds) Insect Conservation Biology, pp. 405–430. London: Royal Entomological Society.

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Hails, Rosemary S(Sep 2009) Environmental Impact of Genetically Modified Organisms (GMOs). In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0003255.pub2]