Evaluating the Impact of Multiple Stressors on Common Loon Population Demographics - An Integrated Laboratory and Field Approach

EPA Grant Number: R829085
Title: Evaluating the Impact of Multiple Stressors on Common Loon Population Demographics - An Integrated Laboratory and Field Approach
Investigators: Meyer, Michael W.
Institution: Wisconsin Department of Natural Resources
EPA Project Officer: Hahn, Intaek
Project Period: October 1, 2001 through March 31, 2005 (Extended to November 25, 2005)
Project Amount: $490,759
RFA: Wildlife Risk Assessment (2001) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Ecosystems , Biology/Life Sciences


Assessing the ecological risk of mercury (Hg) exposure to piscivorous wildlife is a priority issue for federal and state resource management agencies and industry alike. The Environmental Protection Agency (EPA) has designated northern Wisconsin and Michigan's upper Peninsula to be the region at greatest risk to Hg bioaccumulation in the Upper Midwest United States. Wisconsin Department of Natural Resources has evaluated the impact of numerous stressors, including Hg exposure, on common loon (Gavia immer) productivity on the breeding grounds in northern Wisconsin 1991-2000. Over 600 adult loons and chicks on 120 lakes were captured, individually color-marked, mercury exposure determined, habitat variables measured, and reproductive histories and annual return rates quantified. This project uses a rigorous field sampling scheme to produce a random sample of loon breeding pairs from which we calculate the common loon population density and critical population demographic parameters (adult survival, fecundity, and juvenile recruitment) on the breeding grounds. Concurrently, the impact of stressors on these parameters will be quantified. Several stressors are likely associated with impacts on loon demographic parameters including food availability, mercury exposure, shoreline development, predator density, lake morphology, water chemistry, and suitable nest habitat.

Specific objectives include: 1) a systematic random sample of the common loon breeding population in Wisconsin to quantify critical life history parameters necessary to calculate population density and to produce a common loon demographic model; and 2) quantification of the impact of multiple stressors (mercury exposure, habitat alteration, predation, disturbance) on these demographic parameters.


This approach utilizes the dual frame sampling method (incorporating sampling from a list of known loon territories and random area samples) to estimate population abundance and demographics, and to produce the sample of breeding pairs from which stressor impacts will be measured. GIS technologies are used to measure spatially explicit habitat variables.

Expected Results:

The expected results include an estimate of loon population abundance on the breeding grounds, estimates of adult survival, proportion of adults breeding, fecundity, and juvenile recruitment. The impacts of mercury exposure, shoreline housing development, water chemistry and lake morphometry, and lake recreation use on these demographic parameters is quantified. By testing whether these stressors impact demographic parameters we not only assess their ecological importance from a conservation/management standpoint, but also evaluate the potential value of the population/multiple stressor approach for improving Wildlife Risk Assessments. The anticipated results of this study will also fill a critical information need of our understanding of common loon ecology from which regional and national common loon conservation strategies will be derived.

Publications and Presentations:

Publications have been submitted on this project: View all 12 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 4 journal articles for this project

Supplemental Keywords:

methylmercury exposure, habitat alteration, prey abundance, human disturbance, stressors, demographics, EPA Region 5, Wisconsin, survival, fecundity, recruitment, population size., RFA, Scientific Discipline, Toxics, Water, Geographic Area, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Ecosystem/Assessment/Indicators, Ecosystem Protection, exploratory research environmental biology, wildlife, State, HAPS, Ecological Effects - Environmental Exposure & Risk, Ecological Risk Assessment, Ecology and Ecosystems, 33/50, Mercury, EPA Region, ecological exposure, demographic, predicting risk, loon population demographics, demographic data, contaminants, stressors, multiple stressors, Wisconsin (WI), mercury & mercury compounds, Mercury Compounds, impact of stressors on loon population, Region 5, population

Progress and Final Reports:

  • 2002 Progress Report
  • 2003
  • 2004 Progress Report
  • 2005
  • Final Report