Declining bird populations could be still more drastically reduced if farmers troubled by weed-ridden fields use GM herbicide-resistant crops, a study carried out by a group of scientists at the University of East Anglia shows. The impact of their use on farms where intensive agriculture has already massively reduced seed densities would be less severe (ie where intensive agriculture is already having a major negative environmental impact, these crops won't make matters much worse!)
1. American Association for the Advancement of Science press release
2. GM crops threaten skylarks - The Guardian
3. GM crops could drive away birds - The Times
4. Other coverage: urls
5. FoE press release
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1. Farmers and GM crops should both impact farmland birds, Science study predicts
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American Association for the Advancement of Science
This news release is also available in French.
The use of genetically modified herbicide-tolerant (GMHT) crops may severely reduce bird populations on a small percentage of farms, while having little effect on most others, predicts a new study in the 1 September issue of the international journal, Science. Overall, the consequences should depend upon which farmers adopt the new crop types, the study's authors conclude.
The possible effects of GMHT crops on wildlife in the countryside has been the subject of ongoing debate, and the British Government has introduced a moratorium on the use of these crops until the issue is resolved.
Lead Science author Andrew Watkinson, from the University of East Anglia, in Norwich, England, and his colleagues have created a model that simulates the growth of weed populations within crops. Using the model, the team investigated the consequences of the changed herbicide use likely to be associated with GMHT crops. The results showed that weed seed populations can be expected to decline by at least 90% in some cases.
An important part of the study links the decline in weed numbers to bird numbers, predicting that such a decline inseed abundance should seriously reduce the numbers of skylarks using these fields.
The controversial field trials currently underway in the United Kingdom are intended to investigate the consequences of GMHT crops for biodiversity.
"The field trials will be very valuable, but will not tell us what will happen to bird populations. They are carried out on too small a scale. One considerable advantage of the methodology we have adopted is that it enables us to make predictions now rather than having to wait for the results of a three year trial," Watkinson said.
Several decades of intensified agriculture in Europe have had a particularly serious effect on birds, whose populations in the United Kingdom have declined by up to 90 percent in the last 25 years, according to Watkinson.
"It seems likely that the widespread introduction of herbicide-tolerant crops will result in further declines for many farmland birds unless other mitigating measures are taken," Watkinson said.
The model developed by Watkinson's team examines the management of herbicide-resistant sugar beet and its effects on a major annual weed of that crop (Chenopodium album, more commonly known as Lamb's Quarters in North America and Fat Hen in Britain) and the seed-eating skylark Alauda arvensis.
"These results probably apply widely to other crops, weeds, and seed eating birds," noted Watkinson.
The study showed that a key issue in predicting the impacts on bird numbers was the pattern of farmers' uptake of the new GM technology. Most fields have very low seed densities. It's the smaller proportion of fields with high seed densities that is particularly important for bird populations.
The researchers predict that the severity of the bird declines will depend upon which farmers are most likely to adopt the GMHT crops. If their use is restricted to intensive farms with low seed densities then the effect will be minor. However, if the herbicide-hardy crops are adopted by a wide range of farmers--especially farmers with very weedy fields--then the bird declines are likely to be more severe, according to the study.
In their Science paper, Watkinson and his colleagues emphasize that their findings don't just apply to the effects of genetic engineering. The same approach could be used to predict the consequences of other changes in farming practice, they say.
A commentary by Les Firbank, of the Centre for Ecology and Hydrology, in Cumbria, England, and Frank Forcella at the USDA Agricultural Research Station, in Morris, Minnesota, and the University of Minnesota, in St. Paul, Minnesota, accompanies the Science paper.
Firbank and Forcella write that the model provides a "welcome conceptual framework," but that further work will be necessary to resolve some of the model's simplifications. According to the commentary, some data from the United States, where GMHT crops are currently growing, suggest that weed control with GMHT crops may not be as effective as some of the model results indicate.
Such differences emphasize the need for field trials to complement theoretical studies like this one, Firbank and Forcella point out.
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The other members of Watkinson's team are Robert Freckleton, and William Sutherland, of the University of East Anglia, in Norwich, England, and Robert Robinson, of the British Trust for Ornithology, in Norfolk, England. Their study was funded by the University of East Anglia and the Natural Environment Research Council.
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2. GM crops threaten skylarks
Tim Radford
The Guardian
Friday September 1, 2000
Genetically modified crops could spell trouble for skylarks on farms, according to a study published in the US journal Science.
Andrew Watkinson and his colleagues, from the University of East Anglia, fashioned a computer model of what would happen as farmers sowed herbicide-resistant crops, such as sugar beet, and then sprayed them to wipe out the weeds that lower farm yields. They found that the introduction of such crops could reduce weeds by more than 90%.
The drawback is that farmland birds such as the skylark depend on weed seeds such as fat hen, especially in winter. The more weeds in a crop, the greater the number of skylarks in the vicinity.
"For a variety of social, ecological and economicreasons, some farms contain much higher seed densities than others. If farms such as these opt to grow GM crops, the impact on birds could be particularly severe," said Professor Watkinson.
Although there have been claims that GM foods could present a hazard to human health, most of the objections to their introduction in Britain have been based on their effect on wildlife. Researchers in the US have twice proposed that some genetically modified crops could affect monarch butterfly populations.
In Britain, farmland seed-eaters have been in trouble for decades. The linnet has dwindled by more than 40%, the skylark and the yellowhammer by 60% and the tree sparrow by 87% in 25 years.
Field trials for GM crops are about to begin, with the aim of answering questions about their effects on biodiversity. Prof Watkinson believes that valuable as these trials are, they will not reveal much about bird populations.
He said: "They are carried out on too small a scale. One considerable advantage of the methodology we have adopted is that it enables us to make predictions now rather than wait for the results of a three year trial."
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3. GM crops could drive away birds
The Times September 1 2000
GENETICALLY modified crops that are resistant to herbicide could lead to declining populations of farmland birds by removing a major source offood, British researchers claim today (Mark Henderson writes).Skylarks, linnets, yellowhammers and tree sparrows could all be affectedby widespread planting of GM sugar beet because the number of weed seeds in the fields could be cut by as much as 90 per cent, according to a study published today in Science. The adverse effects would be greatest if the GM crops were planted in fields that were not intensively farmed,the team, led by Andrew Watkinson of the University of East Anglia, said.
The use of herbicide-tolerant sugar beet on intensive farms - where it is most likely to be planted - would not be a big problem, the study found.Seed densities on such farms, which are heavily treated with herbicide, are already low and would not fall much further.
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4. Other coverage:
Latest news by category: 08:12
http://www.ananova.com/news/story/sm_51240.html
GM crops 'could imperil bird populations'
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http://news.ft.com/ft/gx.cgi/ftc?pagename=View&c=Article&cid=FT3A56DSKCC&live=true&tagid=ZZZPB7GUA0C&subheading=UKFinancial
Financial Times 1st September 2000
UK
GM crops threat to birds
By Michela Wrong, Food and Biosciences Correspondent
Published: August 31 2000 19:56GMT | Last Updated: August 31 2000
20:06GMT
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5. FoE press release
NEW FEARS OVER IMPACT OF GM CROPS ON BIRD POPULATIONS
New research from the University of East Anglia on the potentially negative effect of GM crops on bird populations is published in Science magazine tomorrow (Friday).Adrian Bebb, GM campaigner at Friends of the Earth comments:
“We have argued since the beginning of the GM debate that introducing pesticide and herbicide resistant crops into the UK countryside may have disastrous environmental effects. This new research provides shocking evidence of what could happen to our farmland bird populations, already in sharp decline because of chemical-heavy intensive farming. By contrast recent research on organic farms showed an increase in skylark numbers.
The UEA research also reveals once again the farcical nature of the Government's so called GM “trials programme”. The research suggests that the trials will fail to pick up any of the environmental effects identified in this study. Since these are fundamental to the environmental case against GM crops, what on earth is the point of the trials? The time has come for the Government to finally call a freeze on GM crops until their safety can be guaranteed. And instead of wasting tax-payers money on dead-end GM research the Government should be investing in farm systems that grow sufficient high-quality food on wildlife-friendly land.”