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Written by Administrator
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Friday, 10 July 2009 06:08 |
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Herbicide use is changing as a result of the rapid adoption of HT crops (ICSU). There has been a marked shift away from more toxic herbicides to less toxic forms, but total herbicide use has increased (Traxler, 2004). Scientists agree that HT crops are encouraging the adoption of low-till crops with resulting benefits for soil conservation (ICSU). There may be potential benefits for biodiversity if changes in herbicide use allow weeds to emerge and remain longer in farmers' fields, thereby providing habitats for farmland birds and other species, although these benefits are speculative and have not been strongly supported by field trials to date (GM Science Review Panel). There is concern, however, that greater use of herbicides - even less toxic herbicides - will further erode habitats for farmland birds and other species (ICSU). The Royal Society has published the results of extensive farm-scale evaluations of the impacts of transgenic HT maize, spring oilseed rape (canola) and sugar beet on biodiversity in the United Kingdom. These studies found that the main effect of these crops compared with conventional cropping practices was on weed vegetation, with consequent effects on the herbivores, pollinators and other populations that feed on it. These groups were negatively affected in the case of transgenic HT sugar beet, positively affected in the case of maize and showed no effect in spring oilseed rape. They conclude that commercialization of these crops would have a range of impacts on farmland biodiversity, depending on the relative efficacy of transgenic and conventional herbicide regimes and the degree of buffering provided by surrounding fields (Royal Society, 2003:1912). Scientists acknowledge that there is insufficient evidence to predict what the long-term impacts of transgenic HT crops will be on weed populations and associated in-crop biodiversity (GM Science Review Panel).
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Last Updated on Friday, 10 July 2009 08:49 |
