Ecological Monitoring of Genetically Modified Crops A Workshop Summary (2001) / Chapter Skim
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Scientific Issues in Ecological Monitoring
Scientific Issues in Ecological Monitoring
Pages 11-20
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From page 11... ...
If, for example, the transgenic crop in question is Bt corn and the concern is that the crop's major pest, the European corn borer, will develop resistance to the Bt toxin, it is necessary to monitor the corn borers for the appearance of genes that confer resistance. "But for many of the other kinds of ecological risks," she said, "it may be less obvious than that." When one is concerned about effects on nontarget organisms, for example, there are likely to be many different organisms in both the crop fields and the ecosystems adjacent to the fields.
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From page 12... ...
" The distribution of the nontarget organisms is another important factor: "Do you choose cosmopolitan species so that you can make some general rules that hold across the United States or across the world, or do you choose organisms that are highly localized in their distribution and yet again may be the ones that are most sensitive to the environmental perturbation that you are putting out there? " Finally, Power said, population stability can make a major difference in the success of monitoring a particular nontarget species: "Choosing organisms that have relatively stable populations seems to give you the opportunity to detect impacts more easily because if you see wild fluctuations you may be able to correlate them in some way with the impact you are interested in.
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From page 13... ...
I cannot answer the question, but what I can say is that it is important to think carefully about what should be required for field experiments, about what is a realistic but effective design for making sure that year-to-year variability has been accounted for." A related issue is that if ecological monitoring is to discover changes in ecosystems caused by the cultivation of transgenic crops, it will be vital to know what those ecosystems were like before the introduction of the transgenic plants. "If you monitor something," Schaal commented, "you need to collect a series of different data points to tell whether anything is changing.
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From page 14... ...
"It is also going to be important to choose carefully which release sites to monitor," she said, "because it will not be feasible to monitor each commercial application of a genetically modified organism." Ultimately, the purpose of monitoring is to help one to understand the risks and benefits associated with transgenic crops and to be able to respond to or manage the risks effectively. So the monitoring should take into consideration the needs at two interconnected stages of risk decisionmaking, risk assessment and risk management.
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From page 15... ...
The challenge is to figure out how to monitor for them under field conditions." As an example, Power described studying the effects of putting viral genes into oats to make the oats resistant to a virus. Research showed that the viral genes did indeed make their way into a companion weed, wild oats, and that the genes made the wild oats resistant to the virus as well.
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From page 18... ...
Before a complete risk assessment is done, for example, risk assessors can decide which areas are more or less likely to involve risk and then assign monitoring intensity on that basis to make it more relevant and useful.
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From page 19... ...
SCIENTIFIC ISSUES IN ECOLOGICAL MONITORING 19 Once the decision has been made to release a transgenic crop, its effects on the surrounding ecosystem can depend heavily on how the crop is managed, and that too has implications for monitoring. "If we want to have adaptive management strategies in which we alter the management of a particular crop, we need to have data on which to base the alterations of management," Schaal said.
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From page 20... ...
Ideally, monitoring should be designed so that it can detect both unexpected and unpredicted events and events that are expected. To illustrate her point, Kapuscinski described how attempts to rebuild selfreproducing salmon populations in the Pacific Northwest backfired when carefully planned spawning interventions resulted in a decrease rather than an increase, in salmon abundance.
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