NEW STUDY FUELS BIOTECH DEBATE

Providing further proof that genetically modified crops may cause unintended harm to wildlife, a new British study found that biologically engineered crops could drastically reduce the populations of seed-eating birds living near farms.

by Danielle Knight

Washington, 31Aug 2000 (IPS) -- Providing further proof that genetically modified crops may cause unintended harm to wildlife, a new British study released Thursday found that biologically engineered crops could drastically reduce the populations of seed-eating birds living near farms.

“Consequent effects on the local use of fields by birds might be severe,” said the study that appeared Thursday in the peer-reviewed academic journal Science, published by the American Association for the Advancement of Science.

The researchers mathematically simulated the effects of the introduction of genetically modified herbicide-tolerant sugar beets on the population of a weed. The weed, known as ‘lamb’s quarters’ or ‘fat hen’, occurs worldwide and is an important source of food for farmland birds.

According to the results, weed seed populations can be expected to decline by at least 90% in some cases. Such a decline should seriously reduce the numbers of skylarks using these fields, the study suggested.

Although the authors selected just one weed and one bird for their model, they presume that their model reflects a wider range of farmland birds and the weeds that are their food source.

Overall, according to Andrew Watkinson and the study’s other authors, the consequences should depend upon whether the farmers who adopt the new crop types wish to apply it to fields where the weeds are already well under control or to fields that are particularly weedy.

Scientific studies like Watkinson’s have been feeding growing public concern worldwide that the new technology has not been adequately tested for negative impacts on environment and health.

In May 1999, the scientific journal Nature reported the results of a Cornell University laboratory experiment in which altered corn pollen killed monarch butterfly larvae.

The corn contains a gene from the natural soil bacterium Bacillus thuringiensis (Bt), which destroys the digestive tracts of butterflies and moths, some of which are pests.

Half of the monarch - cherished by nature lovers for its unique bird-like migration in North America - migrates up through the US corn belt. So the discovery that genetically altered corn pollen will kill non-target species like monarch butterflies alarmed many scientists and made front-page headlines around the globe.

But a later study, heavily promoted by the biotech industry, by researchers at the University of Illinois showed pollen from the genetically modified crop did not harm black swallowtail butterflies.

The day this study was made public, Val Giddings of the Biotechnology Industry Organisation, the industry’s main lobbying group, told reporters that the study “should help clip the wings of last year’s stories hypothesising negative effects of Bt corn on monarch butterflies.”

But the authors of the swallowtail study said that their results do not necessarily mean Bt corn will not have adverse environmental impacts on other species.

“There are a lot of species at risk in the environment, and out of about 100, we now have data points on two - the monarch and the black swallowtail,” added John Losey, the scientist who conducted the Cornell study.

Researchers acknowledge that the controversy surrounding the ecological impacts of biotech crops is far from over. Other scientists have already formally challenged the Watkinson study.

In a related opinion article in the same Science magazine, scientists Les Firbank and Frank Forcella wrote that the Watkinson model provides a “welcome conceptual framework,” but that further work will be necessary to determine the effects of biotech crops on biodiversity.

The study’s conclusion “is questionable in light of experiences with growing (genetically modified) maize, soybean, canola, and sugar beet in the United States,” they said.

Firbank (at the Centre for Ecology ad Hydrology in the United Kingdom) and Forcella (with the US Department of Agriculture) pointed out that data from genetically modified crops grown in the southern United States show that since there is sometimes less success with weed control when growing altered crops, birds could still find the food they need.

“An informal poll among weed scientists indicates that farmers who grow (genetically modified) soybean do so not because weed management with this crop is more effective, but because it is simpler,” they wrote.  When farmers use herbicides on traditional crops, the timing of such chemical applications is often critical.