the general unpredictable outcomes of altered ecosystem interactions. Long-term monitoring to assess potential changes associated with commercialization of transgenic crops is essential. The inherent difficulty in predicting indirect interactions and cumulative or synergistic effects makes the use of long-term monitoring essential in assessments of the environmental effects of new technologies.

Monitoring Transgenic Crops

Systematic monitoring of the spatial and temporal patterns of an area planted with different transgenic varieties will provide a basis for all other monitoring efforts. Ecological effects with a low frequency of occurrence will probably occur in a spatially heterogeneous pattern, and the probability of occurrence will be predicted to be proportional to the area of the transgenic crop planted. Information on the planting pattern will permit use of epidemiological methods (Waggoner and Aylor 2000) to evaluate reports received from the trained-observer monitoring system. Without this systematic monitoring data, it will not be possible to separate coincidental anecdotes from real ecological trends. The information should also be used to plan long-term monitoring sampling plans to optimize effort allocation. Moreover, in any analyses of long-term monitoring, indicator data need to be linked to the spatiotemporal planting pattern.

Annual reporting of this planting pattern is essential. The spatial pattern should be reported at as fine a spatial scale as possible because environmental effects are likely to be localized and aggregation of spatial data may eliminate the correlation between the occurrence of the crop variety and the environmental effect or may induce artificial correlations. The committee suggests that spatial resolution of planting patterns to a 6 × 6 mile grid may be sufficient, but spatial statisticians should develop the appropriate sampling scenario. Because different transformation events associated with the same trait can have different environmental effects (e.g., transgenic corn varieties Event 176 vs. Bt-11/Mon 810), planting patterns should be reported separately for the various transformation events, instead of aggregated across the type of trait within a crop.

Recommendation 6.5: The committee recommends that any postcommercialization monitoring program that is adopted should include monitoring of the spatial distribution of transgenic crops.

Monitoring Using Biological Indicators

The committee recognizes the difficulty in providing sufficient financial and taxonomic expertise to monitor more than a fraction of the biota



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