ARE genetically modified crops a danger to the environment? Perhaps not, if the results of a little-heralded crop trial in Jutland, Denmark, are anything to go by. The trial may provide a sneak preview of the world鈥檚 largest experiment on GM plants, due to finish this summer.
Engineered sugar beet is more friendly to wildlife than its conventional counterpart, the Danish trial suggests. Britain is running a similarly designed, farm-scale evaluation of GM sugar beet, and if this comes up with the same result this summer, one of the key arguments against the technology will disappear. Whether GM oilseed rape and maize measure up too remains to be seen, however.
In their experiments in Jutland from 1999 to 2001, ecologists Beate Strandberg and Marianne Bruus Pedersen compared the environmental impact of conventional beet with that of GM beet resistant to Monsanto鈥檚 broad-spectrum herbicide glyphosate. Crucially, they designed their experiment in a way that allowed them to evaluate the effects of glyphosate when used exactly as instructed on the label.
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Critics of GM technology have argued that if farmers do this their fields will be left sterilised and barren. In Britain鈥檚 farm-scale trials, farmers were asked to stick to the 鈥渓abel-only鈥� regime to make the results representative of what would happen if GM crops were widely grown.
Contrary to expectations, the Danes found that the GM beet was more friendly to wildlife, even when used according to this 鈥渉arsh鈥� regime. 鈥淲hen farmers used it as recommended, we found a doubling of the weed biomass compared with conventional beet,鈥� says Strandberg, who works at Denmark鈥檚 National Environmental Research Institute in Silkeborg. GM plots were also richer in insects, spiders and other arthropods, providing more food for birds than conventional plots.
Earlier this year, British researchers at Broom鈥檚 Barn Experimental Station in Suffolk announced results showing that wildlife flourishes under a less harsh herbicide regime (see New 杏吧原创, 18 January, p 6). A separate part of the Danish trial confirmed this: it found that delaying the application of the herbicide till later than recommended on the label produces a tenfold increase in weeds, and a doubling of the insect population, without damaging yields.
Les Firbank of Britain鈥檚 Centre for Ecology and Hydrology in Merlewood, Cumbria, who is heading the farm-scale evaluation (FSE) project, warns that the Danish trial may be too small to give a reliable foretaste of the three-year British study. 鈥淭he issues that Strandberg is investigating relate closely to those we鈥檙e looking at, but ours include the variations between places and farmers,鈥� he says. 鈥淭he sheer scale is the power of the FSEs, and because of that we can be confident of any generalities that emerge from the results.鈥�
But Strandberg says her trial will be a good indicator of the results from its larger British counterpart. 鈥淲e saw we had very similar things going on,鈥� she says. Both sets of researchers have visited each other鈥檚 projects.
On the downside for backers of the technology, there were hints that GM crops might disturb the balance of weed species in fields, killing many in late summer before they can produce seeds. Strandberg also warns that weeds may not be as bountiful if glyphosate is sprayed year after year. She predicts that the use of GM beet might favour weeds such as dwarf nettles, which are harder for glyphosate to kill, over weeds such as meadowgrass, which succumb quickly. This could have unpredictable effects on farmland biodiversity, say the researchers, although further experiments would be needed to explore them.
At a conference last month in London, Michael Meacher, Britain鈥檚 environment minister, warned that GM crops could legitimately be banned throughout Europe if the farm-scale trials proved they are damaging to the environment. Following this logic, Meacher admitted that if conventional crops are shown to be more damaging to the environment than GM, there might be a day when these could face separate legal sanctions.