Herbicide Tolerant Maize and Biodiversity

The effects of continuous planting of herbicide tolerant maize on diversity of plant and invertebrates were examined by a group of researchers in the United Kingdom. M.S. Heard and his colleagues studied eight maize fields that were previously used for Field Scale Evaluations (FSE). They looked for differences in arable biodiversity when the fields were continuously planted with herbicide tolerant maize instead of being rotated with conventional maize or other cereal crops.

The research group gathered data for two cropping seasons. Some of the biodiversity indicators recorded include weed species abundance, seed rain data, within-field invertebrate species abundance, and vegetation cover. The indicators were obtained before the crops were sown, during the season, and after harvest.

In the first year of cropping, Heard and colleagues observed that weed biomass and seed rain were greater in biotech maize but there was no clear pattern in the second year. This observation about the variation in the effects on individual plant species is consistent with earlier studies. They concluded that research on the field used in FSEs provides little evidence for cumulative effects on biodiversity resulting from continuous planting of herbicide maize.

The full paper in the journal Annals of Applied Biology can be accessed by subscribers at
http://dx.doi.org/10.1111/j.1744-7348.2006.00091.x