Genetically Engineered Crops Damage Wildlife

The study, released on March 21, 2005 was the last of four farm-scale field tri­als. This one com­pared GM winter-sown canola (oilseed rape) with non-GM vari­eties grown side-by-side in 65 plots through­out the UK. For three years, sci­en­tists vis­ited fields 7,000 times and counted a mil­lion weeds and two mil­lion insects. Although the total weed count for the GM and non-GM fields was about the same, the types of weeds were dif­fer­ent. GM fields had about one-third fewer seeds from broad-leaved weeds, and that’s the prob­lem for the birds. Skylarks, tree spar­rows, bullfinches and oth­ers, eat the seeds from these broad-leaved vari­eties. As the weeds decline, so too would the birds’ chances of sur­vival. Also, insects feed on the flow­ers of broad-leaved weeds. This helps explain why the bee pop­u­la­tion among the GM fields was cut by up to half and but­ter­flies by up to two-thirds dur­ing the month of July.

GM crops don’t directly reduce insect- and bird-friendly weeds. It’s the her­bi­cide that they are engi­neered to with­stand that does the dam­age. Of the 170 mil­lion acres of GM crops planted around the world—almost three times the size of the UK—about 80 per­cent have their DNA altered to sur­vive appli­ca­tions of her­bi­cide. Farmers spray over the top of “her­bi­cide tol­er­ant” GM crops, a prac­tice that would kill nat­ural vari­eties. Farmers apply broad-spectrum her­bi­cides to GM crops later in the sea­son and use more of it—lots more. In the U.S., where 64 per­cent of the world’s GM crops are planted, her­bi­cide use has grown by 138 mil­lion pounds over the last nine years. The rate of appli­ca­tion is accel­er­at­ing due to weeds becom­ing immune to the her­bi­cide. Based on pro­jec­tions from recent trends and reports from land grant uni­ver­si­ties, the amount of Roundup her­bi­cide used on GM “Roundup Ready” soy (which com­prises 85 per­cent of the US soy har­vest) is esti­mated to be about 86 per­cent more than that used on non-GM vari­eties in 2004. If the UK tri­als lasted sev­eral more years, the her­bi­cide dosage there would also likely increase and its effects be more pronounced.

Impacts on wildlife vary with the type of GM crop. Two ear­lier UK farm-scale trials—one look­ing at spring-sown GM canola, the other GM beets—showed greater dam­age to but­ter­fly and bee pop­u­la­tions and plant diver­sity than the winter-sown canola. In a fourth trial, wildlife appeared to fair bet­ter in the fields of GM corn. But the non-GM fields were treated with atrazine, a weed killer so toxic, it was banned by the EU two weeks after the field trial ended in October, 2003.

Comparing GM crops to a banned sub­stance should have nul­li­fied the results of the trial. Nonetheless, the pro-GM UK gov­ern­ment approved the corn, but added reg­u­la­tions on how and where the crop could be planted and indi­cated that the com­pany would assume some lia­bil­ity for crop-related dam­age. Unwilling to com­ply with the government’s “obsta­cles,” Bayer CropScience, with­drew its appli­ca­tion for the GM corn three weeks later. Bayer also makes the winter-sown canola that per­formed poorly in the trial. It turns out that 23 out of 25 EU coun­tries had raised objec­tions to the canola being grown in Europe due to both envi­ron­men­tal and health con­cerns. The Austrian response stated, “No data/studies at all on pos­si­ble effects on human health are pro­vided.” The French said the safety of the crop “from the health point of view can­not be guar­an­teed.” Bayer said they wouldn’t even try to grow it in Europe. It is, how­ever, grown in the U.S. and Canada, where stud­ies on health are not required and in-depth envi­ron­men­tal impact assess­ments have not been conducted.

The U.S. gov­ern­ment has been sharply crit­i­cized for allow­ing mil­lions of acres of GM crops to be planted with­out care­fully eval­u­at­ing the con­se­quences. In 1999, after Cornell researchers dis­cov­ered that pes­ti­cide pro­duc­ing GM corn planted around the coun­try may threaten monarch but­ter­flies, a depart­ment of agri­cul­ture offi­cial said, “We knew things like mon­archs and other but­ter­flies would be sus­cep­ti­ble. That’s part of the gen­eral back­ground noise.” Several species of birds in the U.S. are also on the decline, but no stud­ies have been done to see if the increased use of her­bi­cides due to GM crops might be a cause. An arti­cle by the U.S. Geological Survey states, “It seems likely, in fact, that more than enough effort is being expended on mon­i­tor­ing birds, and that some of those resources could use­fully be redi­rected to other…work such as iden­ti­fy­ing causes of declines.”

Large Study, Narrow Focus

The UK farm-scale tri­als were the largest study ever to eval­u­ate the eco­log­i­cal effects of GM crops. Nonetheless, it over­looked more impor­tant data than it gathered.

Contamination of non-GM crops was not ana­lyzed. In Canada, there is so much con­t­a­m­i­na­tion from GM canola, non-GM and organic farm­ers have given up and sev­eral are fil­ing law­suits. Many fac­tors are respon­si­ble for con­t­a­m­i­na­tion, includ­ing wind and insects. Bees can carry pollen more than 16 miles, yet the cur­rent stan­dard sep­a­ra­tion dis­tance between GM and non-GM vari­eties in the UK is 50 meters (expand­able to 200 in cer­tain cases). Canola also cross-pollinates with weedy rel­a­tives such as wild turnip, which become resis­tant to weed killer. The weeds can har­bor the her­bi­cide tol­er­ant gene for years and also trans­fer it to non-GM canola.

Contamination also occurs when unhar­vested seeds fall on the ground and then grow in sub­se­quent years. Studies show that if a farmer plants GM canola for one sea­son and non-GM there­after, his or her har­vest will have GM con­t­a­m­i­na­tion at greater than 1 per­cent for up to 16 years. If the farmer plants a dif­fer­ent crop in the same field, the “vol­un­teer” GM canola becomes a dif­fi­cult weed—resistant to weed killer. In Canada, some plants are resis­tant to three dif­fer­ent her­bi­cides due to cross pol­li­na­tion from mul­ti­ple vari­eties. Farmers have to use more toxic chem­i­cals to con­trol them.

The UK tri­als didn’t exam­ine the ris­ing use of her­bi­cides due to GM crops and the impact on the envi­ron­ment or human health. Since the her­bi­cide is sprayed directly on the GM plants, the food car­ries greater residues. An arti­cle pub­lished on February 24, 2005 in Environmental Health Perspectives found that glyphosate, the active ingre­di­ent in Roundup, had toxic effects and endocrine dis­tur­bances on human pla­cen­tal cells in test tubes. The authors believe this might account for reports of increased pre­ma­ture births and mis­car­riages among women farm­ers using glyphosate. The study also found that Roundup, which con­tains addi­tional ingre­di­ents, was more toxic than glyphosate alone. Similarly, a December 2004 study in Toxicological Science found that Roundup—and not glyphosate alone—damaged the DNA in a way that might increase can­cer risk.

Another area neglected by the farm-scale tri­als was analy­sis of soil ecol­ogy. Laboratory stud­ies have con­firmed that trans­genes from GM crops can trans­fer into soil bac­te­ria, but the impli­ca­tions of this are not understood.

The tri­als did not look at the type of GM crops engi­neered to pro­duce their own pes­ti­cide. These “Bt” crops can kill ben­e­fi­cial insects, cre­ate pes­ti­cide tol­er­ant insects, and put pes­ti­cide into the soil, where it can bind with clay and remain sta­ble for months or years.

A more sig­nif­i­cant area of study that is needed may be the changes to the GM crops’ DNA and phys­i­ol­ogy. The process of genet­i­cally alter­ing a crop can dam­age its DNA, change the out­put of large num­bers of genes, cre­ate unpre­dicted increases or decreases in com­pounds and nutri­ents, and cause genetic insta­bil­ity. One con­tro­ver­sial study pub­lished in Nature found evi­dence sug­gest­ing that the DNA in corn might become unsta­ble after it is cross pol­li­nated with GM vari­eties. The corn DNA appeared to con­tain sev­eral frag­ments of the promoter—genetic mate­r­ial inserted into GM crops with the for­eign genes. If ver­i­fied, this find­ing might mean that the pro­moter makes the DNA unsta­ble, caus­ing genes to frag­ment and scat­ter through the genome. Biotech sci­en­tists were quick to argue against such an inter­pre­ta­tion, but none have both­ered to do fol­low up research on this poten­tially dis­as­trous finding.

Finally, the farm-scale tri­als com­pared GM crops to the chem­i­cal inten­sive mono­cul­ture farm­ing sys­tem that was respon­si­ble for wildlife dev­as­ta­tion. Organic and sus­tain­able farm­ing tech­niques have been shown to reverse dam­age to the ecosys­tem. Shouldn’t some of the mil­lions spent on test­ing also eval­u­ate these alternatives?

In spite of its short­com­ings, the study’s find­ings about threats to bird pop­u­la­tions are sig­nif­i­cant. According to Frank Gill, the Audubon Society’s for­mer chief ornithol­o­gist, “Like the prover­bial canary in the coal mine, birds are pri­mary indi­ca­tors of envi­ron­men­tal health, and what hurts birds also hurts the peo­ple who share the same space.” The trial also left a last­ing impres­sion: The GM traits have cer­tainly spread to non-GM plants, and will per­sist in the envi­ron­ment per­haps for centuries.

Republished with per­mis­sion from Institute for Responsible Technology.