AS ARGUMENTS continue to rage in the US over whether or not genetically
engineered crops kill monarch butterflies, a potential British victim flew into
view last week. The skylark could be a casualty of herbicide-tolerant sugar
beet, warn Andrew Watkinson and his colleagues from the University of East
Anglia in Norwich.
For the agribiotech companies that make the herbicides and modified seeds,
the timing of this finding couldn鈥檛 be much worse. The British government is
carrying out trials on farms to find out if herbicide-tolerant crops harm
wildlife. Environment minister Michael Meacher has warned that he will ban crops
if they turn out to damage biodiversity.
Watkinson and his colleagues have not been out in the fields counting birds,
however. Their conclusion comes from a mathematical model that predicts the fate
of a weed known as fat hen (Chenopodium album), whose seeds are a
favoured food of the skylark. The model predicts that the pattern of spraying
applied to herbicide-tolerant beet could severely cut populations of fat hen to
below the levels found today, and leave the skylarks with no supper to sing for
(see 鈥淏attlefield鈥�).
The researchers reckon the model could also be modified to forecast
the fortunes of other farmland birds.
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The agribiotech industry has rounded on the study, pointing out that skylark
numbers have been falling dramatically for decades and that 鈥減aper studies鈥� are
no substitute for hard scientific data. Both statements may be true, but they
don鈥檛 tell the whole story.
Skylark numbers in Britain have plummeted by 75 per cent over the past 25
years. Their fate typifies that of many species of farmland birds in Britain,
which have suffered more than any in Europe as agriculture has intensified. But
for seed eaters such as skylarks, herbicide-resistant plants are just one
more step on the road to intensification. The new varieties may need less
weedkiller, but what is applied has a more lethal effect.
Here, incidentally, is one reason why genetically modified crops have raised
such passions in Britain, a phenomenon that sometimes mystifies observers from
other countries. Some 76 per cent of land in Britain is under agriculture,
compared with just 35 per cent in the US. So to many Britons the countryside is
synonymous with farmland, and if you remove wildlife from farms the countryside
becomes a wasteland.
But whatever the local sensibilities, to condemn the study because it鈥檚
theoretical, as industry critics have done, is plain daft. The model may not be
perfect, but the only alternative to this approach is to cover the countryside
with modified crops and see how the birds fare. The government-backed crop
trials now under way will only look at how biodiversity changes within the
boundaries of farms, focusing on things such as densities of weeds, seeds and
insects. But birds travel widely, and a few small farm trials are unlikely to
reveal how their numbers will be affected by widespread planting of
herbicide-tolerant crops. Mathematical models can do this, especially when good
data from the farm trials are plugged into them.
All of which brings us back to what the British government will do if the
farm trials and studies such as Watkinson鈥檚 show that, on balance,
herbicide-tolerant crops do damage biodiversity. In such a case, the trials
would give the government enough evidence to impose a ban under British law. But
wider considerations will make this a very difficult course to steer.
Pinning down indirect effects such as harm to wildlife won鈥檛 be
easy鈥攊t鈥檚 not like being able to show that a crop is toxic. Unless the
case is well made, a ban could trigger another trade war with the US, which is
home to at least one of the big agribiotech companies.
And before that, there鈥檚 the European hurdle to jump. Under European Union
rules, biotechnology companies can appeal against a ban. They will argue, as
they are starting to already, that the timetable for spraying modified crops can
be changed to reduce the harmful impacts on wildlife鈥攑erhaps even improve
things. Though there is no way to confirm that farmers follow these timetables,
such arguments may prove difficult to ignore.
So a more canny approach for the government might be to make sure that
farmers who want to sow herbicide-tolerant plants offset any harm they might
cause. Farmers could be required, for example, to leave a percentage of their
land to grow wild. One reason why herbicide-tolerant crops are attractive is
that they promise farmers increased output, and hence profit. If this economic
benefit were removed to pay for extra environmental protection, it鈥檚 likely that
the motivation to plant the crops would quickly disappear.
