Citation:

Grear, J, D E. Nacci, S. Walters, D M. Champlin, AND A KuhnHines. Population Models for Assessing Risks of Multiple Stressors to the Common Loon. Presented at The Society of Enivronmental Toxicology and Chemistry Annual Meeting, Portland, OR, November 14-18, 2004.

Description:

As part of a demonstration project focusing on the Common Loon (Gavia immer), the U.S. Environmental Protection Agency's National Health and Environmental Effects Research Laboratory is using a matrix population modeling framework to integrate demographic information for extrapolation of multiple stressor effects on individuals to the population level. The Common Loon is at high risk for dietary methylmercury and habitat alteration effects, and because it has been the focus of conservation-oriented field observation programs and partnerships, data are available for use in the development and testing of population models. These data are being used in conjunction with published data to compare the merits and implications of differing matrix model formulations and assumptions. In particular, comparisons are being made between differing treatments of density dependence, functional relationships between stressors and demographic rates, and between annually and seasonally (i.e., periodic) structured matrix models. Criteria for these comparisons include ease of parameterization, goodness of fit between models and independent field data, heuristic clarity, extrapolation to other taxa and stressor scenarios, and the types of explorations and predictions enabled by each model

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