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Integrated modeling of pesticide risks to breeding birds in North American agroecosystems
Citation:
Etterson, M., K. Garber, AND E. Odenkirchen. Integrated modeling of pesticide risks to breeding birds in North American agroecosystems. American Ornithological Society, East Lansing, MI, July 31 - August 05, 2017.
Impact/Purpose:
This presentation introduces the new integrated TIM/MCnest model. The model is applied to a risk assessment for 7 pesticides commonly used for corn in Midwestern agroecosystems. The intended audience is the general ecotoxicology community, risk assessors, and stakeholders for the interagency effort for pesticide risk assessment under Section 7 of the Endangered Species Act. We demonstrate clear differences among pesticides in population-level risk for birds. We also show how acute and chronic effects can be rationally combined in a single metric representing overall risk to breeding birds using cornfields and adjacent habitats.
Description:
Pesticide usage in the United States is ubiquitous in urban, suburban, and rural environments. Scientists at the United States Environmental Protection Agency (USEPA) assess the fate of pesticides and the risk those pesticides pose to the environment and non-target wildlife. We present a new model, the integrated TIM/MCnest model, which allows risk assessors to estimate the effects of pesticide exposure on the survival and seasonal productivity of birds using agricultural fields. The model is applied to assess the relative risk of several alternative insecticides on a suite of 31 avian species known to use cornfields in midwestern agroecosystems. The insecticides that were assessed, i.e., carbaryl, chlorpyrifos, indoxacarb, ë-cyhalothrin, malathion, methomyl, and permethrin, are all used to treat major pests of corn (corn root worm borers, cutworms, and armyworm). We found extensive differences in risk among pesticides, with chlorpyrifos and malathion (organophosphates) generally posing the greatest risk, and bifenthrin and lambda cyhalothrin (pyrethroids) posing the least risk. Life history parameters related to the timing of breeding and reproductive output per nest attempt offered the greatest explanatory power for predicting the magnitude of risk. The integrated TIM/MCnest model is a promising start towards true population level risk assessment for pesticides using fate and toxicity data required by the Federal Insecticide Fungicide and Rodenticide Act.