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How does temporal variability in model parameters affect the risk conclusions from MCnest?
Citation:
Etterson, M. How does temporal variability in model parameters affect the risk conclusions from MCnest? SETAC North America, Salt Lake City, UT, November 01 - 05, 2015.
Impact/Purpose:
not applicable
Description:
USEPA recently began using the MCnest model for avian risk for adverse reproductive effects due to pesticide exposure. A more advanced version is currently under development and beta testing for use with threatened and endangered birds. For both versions, a species database has been compiled, containing information such as nest predation rates during egg-laying and incubation and during the nestling period, duration of renesting intervals following successful versus failed nests before a female will initiate a new nest, and species typical clutch sizes. This database allows users to compare potential pesticide effects on species with different life histories. Our current assumption in running MCnest is that these parameters do not change over the course of a single breeding season. However, when ecologists have investigated temporal variation in such parameters, they have often found it, particularly in studies of avian nest survival, though such studies remain infrequent for nest survival and clutch size, and virtually nonexistent for renesting intervals. Furthermore, studies that have found temporal variation, often describe conflicting patterns among species and populations, suggesting that such variation is dependent on environmental context in which the population occurs. I explore the importance of such variation to the risk conclusions produced by MCnest and the potential for such variation to interact with the timing of exposure events.