The results of the world's largest study of genetically modified (GM) crops' impact on biodiversity, completed last month in the United Kingdom, were mixed and limited. But the huge scale of the project is ensuring that the results are being carefully digested across the whole of Europe.

The mixed results, with GM oilseed rape and sugar beet faring badly while maize appeared to have beneficial results for the environment, have provided ammunition for proponents and opponents of genetically modified organisms (GMOs) contacted by The Scientist. “People in favor of GMOs say the results mean we should analyze all crops case by case,” says Daniel Evain, a French farmer and keen observer of the GMO debate as a former agronomist with Monsanto, a food biotechnology company.

This line also has a significant number of advocates in Germany, according to Hartmut Meyer, coordinator for the European NGO-Network on Genetic Engineering. “These results have had quite an impact, at least in so far as they make clear that you can't have a one-size-fits-all approach to risk assessment,” says Meyer. “You have to look in a specific country and circumstance.”

On the whole, the UK Farm Scale Evaluation (FSE) results have tended to swing journalists and opinion formers against GMOs within Europe, certainly in France, Evain argues. “Before the results, they were either in favor or agnostic,” says Evain, “but now they tend to be more skeptical, asking more questions.”

However, biotechnology companies have taken great heart from the results, according to Bernard Marantelli, spokesman for the Agricultural Biotechnology Council representing biotech companies such as Monsanto and Dupont. “The results show that GM crops can be grown in a flexible manner, with benefits for biodiversity. An aspect of the results that was not well publicized was that the three GM crops in the FSE trials all had reduced amounts of spraying, compared with the non-GM versions,” notes Marantelli.

The FSE trials concentrated on the effect on biodiversity of managing genetically modified herbicide-tolerant (GMHT) plants compared with conventional varieties, with particular emphasis on weeds within crop fields. About 180 fields in total were sown with maize, sugar beet, and spring oilseed rape in equal proportions. “The results were quite clear for two of the crops, the beet and the oil seed rape—there was no doubt that wildlife was reduced for those spots that have GMHT,” says Professor Joe Perry, the statistician with co-responsibility for design of the FSE studies and analysis of the results within the consortium conducting the research.

For maize, the results were completely the other way around, but the fact that the herbicide atrazine, used to control weeds for the non-GM part of the study, had just been banned throughout the EU puts the relevance of those results in some doubt. However, the study's architects suggest that the results would have been broadly similar if alternative herbicides to atrazine had been used.

The results will shape public policy and determine the fate of applications involving release of GMOs throughout the European Union for years to come, says Perry. According to Chris Pollock, chair of the scientific steering committee for the £5.9 million ($10 million) FSE study, the results will provide the baseline data for ecological modeling and extrapolation of the impact of GMO crops on biodiversity worldwide. “This is a bloody good piece of science and will have a huge impact in its subject area for a long time to come,” says Pollock. The results go beyond the GM issue, Pollock insists. “The essence here is the new agronomy. The natural balance in a country like Britain where wildlife and farming go hand in hand is very sensitive between productive and nonproductive use of photosynthesis.”

Although statistically powerful, the FSE study was confined to biodiversity. And according to Perry, further trials are needed to provide more data on contamination by GM crops of conventional crops growing in the vicinity. As he points out, the maximum limit for GM contamination tolerated throughout the European Union has been reduced from about 1% to 0.09%. “There's not much data about contamination at such very low levels,” Perry notes. The GM community is eagerly awaiting two UK studies looking at contamination both at very low levels and over long distances resulting from wide-ranging pollinators or unusual winds, but these are not due to report for up to 3 years.

Among other studies still needed are further investigations of different GMO categories, including crops engineered for virus resistance, according to Meyer.

The problem is that such studies would be expensive on the scale required for statistical significance, at a time when public resistance to GM foods is hardening across Europe. GM farmers are having to cope not just with vandalism from protesters, but with growing difficulty obtaining insurance. A recent UK survey by the campaigning group FARM found that many leading UK insurers will no longer provide indemnity cover for liabilities arising from growth of GM crops, such as claims from neighboring farms over contamination.