Climate-change impacts on fish and wildlife habitat in coastal wetlands of Georgian Bay

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Between May 1998 and January 2000, the water level in Lake Huron dropped a meter from 176.91 m above sea level (asl) to 175.92 m. During the following decade, mean monthly water levels averaged 176.0 m asl, and levels are expected to drop even further by the end of 2012. Such a drop in water levels in the Great Lakes has been predicted by Global Circulation Models as a manifestation of global climate change. The water-level decline has dried up many coastal wetlands in Georgian Bay (eastern arm of Lake Huron), which are known to provide critical habitat for fish and wildlife species. Our research showed that in 7 wetlands, an observed drop of 80 cm over a ten-year period (1999-2009) corresponded to an average of 25% of aquatic habitat being converted to terrestrial habitat. This water-level drop also disconnected a fifth of all wetlands from Georgian Bay, and has prevented seasonal access of migratory fish into spawning and nursery habitat. Besides its impact on migratory fish, loss of wetland habitat may also have a negative effect on semi-aquatic turtles such as the Blanding's turtle, which use coastal wetlands as staging areas to feed prior to their nesting migrations. The primary goal of this proposal is to determine the relationship between fish and wildlife habitat and water level in different regions of Georgian Bay, including a southern site where the low water level is confounded with human development, a northern site that is primarily undisturbed by human activities, and islands with and without coastal wetlands. I will use radio-transmitters to determine the spawning and nursery habitat used by northern pike and muskellunge and a combination of GPS-enabled radio-telemetry and surveillance cameras to determine aquatic and terrestrial habitat used seasonally by the Blanding's turtle. The information will be incorporated into a Geographic Information System and supplemented with bathymetric and contour data to build habitat-suitability models for each species. I will then quantify the amount of critical habitat as a function of different water-level scenarios for representative sites throughout Georgian Bay. A second goal is to understand the impacts of diking as a possible mitigation measure to prevent wetland dessication.