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Literature Review on Impacts of GM Crops on Biodiversity

March 2011: This academic research article, authored by Janet E. Carpenter and published in the Journal Landes Bioscience, conducts a review of the existing peer-reviewed literature on potential impacts of genetically modified (GM) crops on biodiversity.

The review takes a "biodiversity lens" to the literature covered, focusing on impacts on the crop, farm and landscape scales. Specifically, it investigates the impact of GM crop introduction on crop diversity, non-target soil organisms, weeds, land use, non-target above ground organisms, and area-wide pest suppression. It also considers impacts of changes in management practices, such as tillage and pesticide use.

The author comes to the conclusion that the overall impacts of currently commercialized GM crops on biodiversity have been positive. GM crops have reduced the impacts of agriculture on biodiversity through enhanced adoption of conservation tillage practices, reduction of insecticide use, use of more environmentally benign herbicides, and increasing yields to alleviate pressure to convert additional land for agricultural use.

Specific conclusions include: impacts of GM crops on crop diversity have not been thoroughly studied, but existing studies suggest that GM crops have not decreased crop diversity; the potential impacts of Bacillus thuringiensis (Bt) crops on soil organisms are well studied, with few or no effects reported on soil organisms, while pest populations have declined in areas with high rates of Bt crop adoption; the introduction of herbicide tolerant crops has facilitated the adoption of conservation tillage, which is expected to decrease erosion, improve water retention and decrease pesticide runoff; and adopters of GM crops have reduced insecticide use and switched to more environmentally-friendly herbicides.

Furthermore, the author notes that current and future technologies offer additional promise of alleviating pressure from agriculture on biodiversity through increased yield and decreased insecticide use. Other technologies such as drought and salinity tolerance could reduce pressure to convert high biodiversity land to agriculture by allowing cultivation suboptimal soils, in particular in sub-Saharan Africa. Nitrogen use efficiency technology could increase yields in areas with limited access to fertilizer and reduce nitrogen runoff. [Publication: Impacts of GM Crops on Biodiversity]