GM crops harmful to wildlife / Farm Scale Evaluations published
*GM CROPS HARMFUL TO WILDLIFE - GeneWatch UK
*Farm Scale Evaluations published - Science Media Centre
GM crops harmful to wildlife: another reason to halt commercialisation
For immediate release - Thursday October 16th 2003
GeneWatch UK response to publication of the farm-scale evaluation results
The results of the farm-scale evaluations, published today, have shown that if GM herbicide tolerant oilseed rape or sugar beet are grown in the UK, farmland biodiversity is likely to suffer (1). The farm-scale evaluations were commissioned in 1998 as a response to public concerns over the impacts of growing GM crops.
"The UK's farmland wildlife has been decimated by intensive farming. If we grow herbicide tolerant crops here it may be the final nail in the coffin for some species," said Dr Sue Mayer, GeneWatch UK's Director. "These results come on top of the economics review which showed there was little economic benefit for the UK, the findings of the public debate showing lack of public support, and new evidence about cross-pollination. It would be foolhardy to proceed with commercialisation."
Previously, the Government's scientific advisors, ACRE, had said that the GM oilseed rape tested in the farm-scale evaluations "did not pose a risk in terms of human health and environmental safety for the United Kingdom" (2) and the UK Government had agreed to marketing of the oilseed rape, but this was prevented because other European countries opposed it.
"The UK's scientific advisors had given the GM oilseed rape a clean bill of health in 1997. It was only public opposition that forced more research on environmental effects. The public seem to have a better grasp of science and what lack of knowledge can mean than the 'experts','' said Dr Mayer. "If the experts' advice had been followed, we could have been growing this damaging crop in the UK for the past five years. It's time the scientific establishment took a more rigorous approach to the risks of GM."
GM herbicide tolerant maize was also included in the trials and, although it did not show the same degree of harmful effects to the environment as conventionally grown maize, many questions remain about the long-term impacts of the GM maize and problems of contamination of non-GM maize have not been resolved.
"These results should not be seen as a green light for GM maize. Two unsustainable systems were being compared and experience in the US shows the trials were not representative of what would happen in reality," said Dr Mayer. "And the problem of contamination of non-GM maize may not be resolvable."
FOR MORE INFORMATION:
Contact Sue Mayer on 01298 871898 (office) or 07930 308807 (mobile).
NOTES TO EDITORS:
1) The results of the farm-scale evaluations are available at
2) See: Index of public register entries for 'Notifications to Market GMOs Under Directive 90/220/EEC', page 22. Reference C/BE/96/01 for GM herbicide tolerant oilseed rape (MS8xRF3). The Advisory Committee on Releases to the Environment (ACRE) gave its opinion on 19th March 1997 and the Government notified the European Commission that it agreed to marketing on 26th March 1997. http://www.defra.gov.uk/environment/gm/regulation/pdf/market.pdf .
Farm Scale Evaluations published today
16 October 2003
PRESS RELEASE: Science Media Centre
The publication today of the results of the Farm Scale Evaluations (FSEs) in Philosophical Transactions: Biological Sciences, a journal of the Royal Society, reveals significant differences in the effect on biodiversity when managing genetically modified herbicide-tolerant (GMHT) crops as compared to conventional varieties. The study emphasises the importance of the weeds growing among crop plants in sustaining natural communities within and adjacent to farmer's fields.
About 60 fields each were sown with beet, maize and spring oilseed rape. Each field was split, one half being sown with a conventional variety managed according to the farmer's normal commercial practice for weed control, the other half being sown with a GMHT variety, with weeds controlled by a broad-spectrum herbicide (glufosinate-ammonium in maize and spring oilseed rape, and glyphosate in beet). Comparisons in biodiversity were made by looking at the levels of weeds and invertebrates, such as beetles, butterflies and bees, in both the fields and the field margins immediately surrounding them.
A total of eight papers are published - two looking at the effects on weeds in the fields, two looking at the effects on invertebrates in the fields, one looking at weeds and invertebrates in the field margins and one looking at the effect of the contrasting herbicide regimes on both weeds and invertebrates as a whole. Another looks at the background to the study and the rationale for its design and interpretation and a final paper compares the management of the crops in the study with current conventional commercial practice to provide readers with contextual information against which the results should be considered.
Effects on weeds in fields (1,2)
The study showed significant and variable impacts of GMHT cropping in beet, maize and spring oilseed rape on the arable weeds when compared to current commercial practices. In GMHT beet and oilseed rape crops more effective weed control led to the decline of the number of weed seeds left in the soil at the end of each growing season (known as the seedbank). Although this has been going on in cropped fields in Britain for many decades it could be accelerated by the management associated with these particular crops. In contrast, GMHT maize showed the opposite effect. Typically conventional maize has lower weed burdens because of the widespread use of persistent herbicides - the herbicide regimes used on the GMHT maize were not as effective at controlling the weeds.
In beet and oilseed rape, the densities of weeds shortly after sowing were higher in the GMHT treatment. This effect was reversed after the first application of broad-spectrum herbicide in the GMHT treatments. By the end of the season, the weight of weeds collected from a fixed area (biomass) and number of weed seeds falling to the soil (seed rain) in these GMHT crops were between one-third and one-sixth those of conventional treatments. The changes in seed rain affected the seedbank, resulting in seed densities about 20% lower in the GMHT treatments.
In maize the effect was different. Weed density was higher throughout the season in the GMHT treatment. Biomass was 82% higher and seed rain was 87% higher than in conventional treatment. However, this had no detectable effect on the seedbank as total seed return was low after both treatments.
Twelve of the most common weed species in the UK were examined. The biomass of six species in beet, eight in maize and five in oilseed rape was significantly affected. Generally, biomass was lower in GMHT beet and oilseed rape and higher in GMHT maize. Significant effects on seedbank change were found for four species of weed. However, for many species in beet and oilseed rape (19 out of 24 cases), seed densities were lower in the seedbank after GMHT cropping. These differences, if compounded over time, could result in large decreases in population densities of arable weeds. In maize, populations may increase.
Effects on invertebrates in fields (3,4)
Differences in GMHT and conventional crop herbicide regimes had a significant effect on the capture of most surface-active invertebrate species and larger groupings (higher taxa) in at least one crop, with most increases occurring in GMHT maize and most decreases occurring in GMHT beet and oilseed rape. One species of carabid beetle that feeds on weed seeds was less frequent in GMHT beet and oilseed rape, but more frequent in GMHT maize, showing how the numbers in some invertebrates tracked the amounts of food available to them.
Most higher taxa of invertebrates active on weeds and in the litter layer were little affected by the treatment. However, smaller numbers of butterflies were recorded in GMHT oilseed rape and smaller numbers of bees, butterflies and Heteroptera ('true bugs') were found in GMHT beet.
However, in all crops under GMHT management there were significantly more Collembola, a type of detritivore known as a 'springtail', which feeds on dead and decaying weeds. This is because the herbicides were applied later in the GMHT crops, and so weeds tended to be larger when killed, providing more food for these insects.
Effects on weeds and invertebrates in field margins (5)
Three components of field margins were sampled: the uncropped tilled area, the field verge (the grassy strip between the tilled land and the fence or hedgerow that forms the actual field boundary) and the boundary itself. In oilseed rape, the cover, flowering and seeding of plants were 25%, 44% and 39% lower, respectively, in the GMHT tilled margin. For beet, flowering and seeding were 34% and 39% lower in the GMHT margins. For maize, the effects were reversed, with plant cover and flowering 28% and 67% greater in the GMHT half. These results corresponded to the effects on weeds within the crops, because these plants had also been affected by the herbicide. Fewer, smaller effects were found in the verges and boundaries, and levels of herbicide damage were low.
24% fewer butterflies were counted in margins of GMHT oilseed rape, reflecting differences in the amount of flowers available. Few differences were found for bees, slugs and snails, or other invertebrates sampled in the field margins.
Effects on plants and invertebrate trophic groups (6)
The effect of GMHT cropping on the interaction between invertebrates with different feeding habits was studied by examining the relations between plants and the abundance of insects grouped according to their feeding preferences (trophic groups). The negative effect of GMHT cropping on weeds in beet and spring oilseed rape, and the positive effect in maize, resulted in similar changes higher up the food chain.
Where the weed flora was less abundant, there were fewer herbivores, pollinators and natural enemies (the insects which prey on the herbivores). Detritivores increased under GMHT management across all crops due to the greater input, later in the season, of dead weeds on which they feed. Compared to large differences through the season and between crop species, GMHT management imposed relatively small (less than twofold), but consistent, differences in the abundance of most trophic groups. The direction of change depended on how effective the herbicide was compared to conventional management.
Rationale and interpretation (7)
This paper provides the background information that was analysed to guide and interpret the FSEs. Previous surveys of soil, vegetation and field management were used to ensure that the chosen fields were typical and representative of commercial practice. Knowledge of the plants and invertebrates, and their sensitivity to the GMHT crop and herbicide, was used to guide the sampling plans applied to each field-half. Historical and recent changes in the buried, living weed seeds - the seedbank - were used to assess the initial diversity of sites and the longer term trends that might result from growing GMHT crops. Re-interpreting field experiments from the 1990s indicated that changes in management practice may cause large differences in biodiversity (e.g. a 50% difference). The experiment was designed to ensure that such differences between conventional and GMHT management would be detectable.
Crop management and wider UK context (8)
It was important that the crop management systems on the studied sites reflected the activities of farmers in the UK countryside. The locations of field sites and intensities of cropping had to represent the range found in the UK and this was found to be the case.
The amounts of herbicide used, and when it was applied, were recorded and compared well with current commercial practice for conventional crops, and the industry-recommended guidelines for application to GMHT crops.
Comparison of the amounts of herbicide applied with the density of weeds showed that farmers applied more herbicide when the density increased in beet and maize. Generally GMHT crops were found to receive less herbicide, later in the season, than the conventional crops.
Commenting on the results, Dr Les Firbank, Centre for Hyrdrology and Ecology, Merlewood, and co-ordinator of the project that submitted the papers, said: "The results of these Farm Scale Evaluations reveal significant differences in the effect on biodiversity when managing genetically herbicide-tolerant (GMHT) crops as compared to conventional varieties. The study emphasises the importance of the weeds growing among crop plants in sustaining natural communities within, and adjacent to, farmer's fields."
"One of the key points to remember is that the results are only applicable to the three crops studied, and only under the regimes of herbicide usage which were employed. Each new application of GM crop technology must be looked at on a case-by-case basis, using a rational evidence-based approach."
1. Weeds in fields with contrasting conventional and genetically modified herbicide-tolerant crops. I. Effects on abundance and diversity
2. Weeds in fields with contrasting conventional and genetically modified herbicide-tolerant crops. II. The effects on individual species
3. Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. I. Soil-surface-active invertebrates
4. Invertebrate responses to the management of genetically modified herbicide-tolerant and conventional spring crops. II. Within-field epigeal and aerial arthropods
5. Invertebrates and vegetation of field margins adjacent to crops subject to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide-tolerant crops
6. Responses of plants and invertebrate trophic groups to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide-tolerant crops
7. On the rationale and interpretation of the Farm Scale Evaluations of genetically modified herbicide-tolerant crops
8. Crop management and agronomic context of the Farm Scale Evaluations of genetically modified herbicide-tolerant crops
NOTES FOR EDITORS
1. Papers featured in this publication do not reflect the Society's views or policies.
2. Please acknowledge The Royal Society Philosophical Transactions B as the source for any item used.
3. The papers can be accessed free-of-charge at
www.pubs.royalsoc.ac.uk/FSEresults from 10.30am BST on Thursday 16
4. Philosophical Transactions B is published by the Royal Society and publishes peer-reviewed research in all aspects of biology, including clinical science. Transactions publishes theme issues devoted to an area of advancing research and discussion meeting issues publishing proceedings of two-day scientific symposia led by the world's leading researchers.
5. The research was undertaken by a consortium made up of The Centre for Ecology and Hydrology, Rothamsted Research and the Scottish Crop Research Institute. The work was overseen by a scientific steering committee made up of experts in the field. For more information go to:
6. An Advisory Board of internationally distinguished scientists and experts in the field was appointed to assist the Editor, Professor Semir Zeki. The Advisory Board also included eminent broadcaster Sir David Attenborough in order to maintain a broader perspective on the desirability of publishing the papers. The composition of the board was as follows:
Professor Dr Muhammad Akhtar FRS Emeritus Professor of Biochemistry at the University of Southampton; Director General of the School of Biological Sciences, University of the Punjab, Lahore, Pakistan; and Member of the Third World Academy of Sciences. Sir David Attenborough CH FRS Broadcaster. Professor Roland Douce Director of the Institute of Structural Biology, Grenoble, France; and Member of the French Academy of Sciences and the National Academy of Sciences, USA. Dr Gurdev Singh Khush FRS Visiting Professor at the Department of Vegetable Crops, University of California, Davis, CA, USA; former Director of the International Rice Research Institute; and Member of the American National Academy of Sciences, USA and recipient of the World Food Prize 1996. Professor Daniel Simberloff Director, Institute for Biological Invasions, Department of Ecology and Evolutionary Biology, University of Tennessee, TN, USA; and Member of the National Science Board (USA).
7. The Royal Society is an independent academy promoting the natural and applied sciences. Founded in 1660, the Society has three roles, as the UK academy of science, as a learned Society, and as a funding agency. It responds to individual demand with selection by merit, not by field. The Society's objectives are to:<br>* strengthen UK science by providing support to excellent individuals * fund excellent research to push back the frontiers of knowledge * attract and retain the best scientists * ensure the UK engages with the best science around the world * support science communication and education; and communicate and encourage dialogue with the public <br>* provide the best independent advice nationally and internationally promote scholarship and encourage research into the history of science.
For further information contact: Becky Morelle