Spatial and temporal analyses of environmental contaminants and trophic status of bald eagles in the Great Lakes region

An evaluation was conducted of spatial and temporal contaminants and trophic status of nestling bald eagles used in contaminant monitoring programs in Michigan and Ohio. The Michigan Department of Environmental Quality (MDEQ) implemented a monitoring program in 1999 using the bald eagle to monitor trends of contaminants. The monitoring program allowed for contaminant assessment at five geographic scales. After completion of the first five-year monitoring cycle, this study concluded that the monitoring program achieved its objective and detected significant decreases in total PCB and p,p'-DDE concentrations in plasma of nestling bald eagles between 1987--1992 and 1999--2002. The five-year sampling method also achieved the sample size objectives needed for precision, mean power, and mean trend analyses at all five geographic scales. Stable isotopic analysis of nestling feathers in Michigan from 1999--2001 showed that nitrogen isotopes can be used to differentiate between known bird and fish consuming nestling eagles. Knowledge of the current prey base utilized by species within the Michigan aquatic food web is important for implementing management decisions and regulations that concern wildlife and human health. The MDEQ bald eagle contaminant monitoring program is, therefore, an appropriate means of detecting trends in contaminants in Michigan.;The Ohio Environmental Protection Agency and Ohio Department of Natural Resources implemented a nestling bald eagle biosentinel program in Ohio in response to research needs expressed by the Lake Erie Lakewide Area Management Plan committee and the Lake Erie Quality Index committee related to exposure to persistent toxic substances to the population of bald eagles nesting along the Ohio portion of Lake Erie. Plasma concentrations of total PCBs, p,p '-DDE, alpha-chlordane, and dieldrin from Lake Erie region nestlings were greater than concentrations from Inland Ohio region nestlings. No overall significant differences in plasma contaminant concentrations over the time period of 1994 to 1997 were detected. This study matched the Lake Erie Commission priorities of protecting Lake Erie's natural resources, restoring degraded elements of the Lake Erie ecosystem, and in supporting monitoring for the Lake Erie Quality Index. These data can be used to complete the development of the bald eagle as a biosentinel species for Lake Erie.;This dissertation research has shown that nestling bald eagles can be used to monitor the spatial and temporal trends of environmental contaminants in the Great Lakes region. Bald eagles have been shown to be an appropriate indicator of Great Lakes environmental quality. Therefore, use of nestling bald eagles in contaminant monitoring studies is an effective approach to monitor contaminant concentrations.