- 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 economic reasons, 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."
