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Policy, uncertainty, and the ecologi...

Hagen, Joy Anna.

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Policy, uncertainty, and the ecologist: Mobilizing science to inform risk assessment of transgenic Bt crops.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Policy, uncertainty, and the ecologist: Mobilizing science to inform risk assessment of transgenic Bt crops./
作者:	Hagen, Joy Anna.
面頁冊數:	184 p.
附註:	Adviser: Deborah K. Letourneau.
Contained By:	Dissertation Abstracts International69-02B.
標題:	Biology, Ecology. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3301333
ISBN:	9780549465270

Policy, uncertainty, and the ecologist: Mobilizing science to inform risk assessment of transgenic Bt crops.
Hagen, Joy Anna.

Policy, uncertainty, and the ecologist: Mobilizing science to inform risk assessment of transgenic Bt crops. - 184 p.

Adviser: Deborah K. Letourneau.

Thesis (Ph.D.)--University of California, Santa Cruz, 2008.

Research on environmental risks of GM crops is vital for effective policy because scientific uncertainty associated with novel technologies forces policy makers to sift through contradictory data, analyses, and claims. I examine the types of ecological risk assessment studies that have gained acceptance in the U.S. and explore the forces impacting the mobilization these studies. My conversations with regulatory, academic, and industry scientists indicate that differences in tradition and definition of risk assessment, along with pre-existing regulatory structures and policies, contribute to how ecological science is mobilized for risk assessment of GM crops. One ecological risk is the increased fitness, competitive ability and invasiveness of plants with fitness-enhancing transgenes (either crops, or sexually compatible wild-relatives that could receive a transgene through gene flow). Risk assessment research on the impacts of insect herbivores on plant population dynamics is vital, but such research is limited by biosafety constraints; releasing experimental transgenes into ecosystems constitutes the very risk such research hopes to test. To assess a surrogate method that can be used without containment limitations, I tested Bt-spray applications as a simulation for transgenic expression of Bt-endotoxins, comparing herbivore exclusion using sprays to transgenic Bt in Brassica napus L. Bt sprays were used in field experiments on wild radish (Raphanus sativus L.) and wild mustard ( Brassica rapa L.) to assess plant population dynamics under different herbivory treatments. The contribution of lepidopteran herbivory at each stage of the life cycle to the overall decrease in population growth was explored using Life Table Response Experiments, showing that insect-resistance can convert stable population trajectories into increasing ones and contribute invasiveness. However, damage by Bt-susceptible herbivores affected wild radish and mustard populations differently. Although wild radish and mustard are closely related plants, the mechanisms by which decreased herbivory contributes to population growth are different. Seedling survivorship in wild mustard contributes to increased rates of spread, while survivorship of young plants and increased seed output contribute to rates of spread for wild radish. I discuss the opportunities and constraints of the invasive species model for risk assessment of transgenic crops.

ISBN: 9780549465270Subjects--Topical Terms:

1017726
Biology, Ecology.

Policy, uncertainty, and the ecologist: Mobilizing science to inform risk assessment of transgenic Bt crops.
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