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Thursday, 31 August, 2000, 18:43 GMT 19:43 UK
GM crops 'could kill off birds'
Lark
Could the lark soon be singing for its supper?
The use of GM crops that can tolerate herbicides may severely reduce bird populations on some farms, according to a study.

Researchers have created a mathematical model that simulates the growth of weed populations within crops.

Using the model, Professor Andrew Watkinson and colleagues from the University of East Anglia, in Norwich, UK, found that weed seed populations could decline by 90% in some cases where herbicide-tolerant (GMHT) crops have been sown.

An important part of the study links the decline in weed numbers to bird numbers, predicting that such a decline in seed abundance would seriously reduce the number of skylarks, in particular.

Trials on trial

Several decades of intensified agriculture in Europe have had a particularly serious effect on birds. Some populations in the United Kingdom have declined by up to 90% in the last 25 years.

Controversial field trials currently underway in the United Kingdom are intended to investigate the impact of herbicide-tolerant crops on 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," Professor Watkinson said in Science magazine.

"It seems likely that the widespread introduction of herbicide-tolerant crops will result in further declines for many farmland birds unless mitigating measures are taken," Professor Watkinson said.

Fat Hen
Weeds like Fat Hen provide vital food for birds
The model developed by Watkinson's team looks at the effects of herbicide-tolerant sugar beet on a weed known as Lamb's Quarters in North America and Fat Hen in Britain, and on the seed-eating skylark Alauda arvensis.

The study showed that a key issue is how farmers use GM crops. Most fields have very low seed densities. It's the smaller proportion of fields with high seed densities that are particularly important for bird populations.

The researchers predict that if the use of GMHT crops is restricted to intensive farms with low seed densities then the effect on bird populations will be minor.

But if farmers with very weedy fields adopt the herbicide-hardy crops then the bird declines are likely to be more severe, according to the study.

Informed decisions

Monsanto, a company in the forefront of GM crop development, warned the study should be viewed with caution because it does not reflect real farming conditions.

Monsanto said biotechnology is not the villain. It is possible to achieve the same level of weed control, and hence the same impact on bird populations, using traditional pesticides, tilling and other methods.

In fact, the company argued, GM crops will be kinder to birds.

"Herbicide-tolerant plants allow farmers to maintain weeds longer in sugar beet fields, which could offer greater resources at a time of year when for birds food is scarce," said Scarlett Foster, public affairs director for Monsanto.

The company claimed that the whole point of herbicide-tolerant crops is to help reduce the amount of chemical herbicides used on the land.

It claimed that a study by the US National Centre for Food and Agricultural Policy showed that soybean growers had actually decreased the use of herbicides by 16 million applications, or roughly 20%.

A leading UK bird conservation group, the British Trust for Ornithology, agrees the study's findings should be treated with caution and supports the need for field trials.

"We have got to look at real data in the real world before we can make informed decisions," said Trust spokesman Chris Mead.

"There are millions of acres of this stuff being grown elsewhere in the world and Britain simply can't hold out for ever. What's vital is that we look at the impact of GM crops on birds in real-life terms to find out what the actual, not theoretical, effects will be."

Friends of the Earth welcomed the group's findings.

"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," said FOE GM campaigner Adrian Bebb.

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