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

1998年5月至2000年1月，休伦湖的水位从海拔176.91米下降到175.92米。在接下来的十年中，月平均水位平均为176.0米，预计到2012年底水位将进一步下降。五大湖的水位下降已经被全球环流模型预测为全球气候变化的一个表现。水位的下降使乔治亚湾（休伦湖的东岸）的许多沿海湿地干涸，这些湿地是鱼类和野生动物的重要栖息地。我们的研究表明，在7个湿地中，在10年期间（1999-2009）观测到80厘米的下降，相当于平均25%的水生栖息地转变为陆地栖息地。水位下降还切断了乔治亚湾五分之一的湿地，阻碍了季节性洄游鱼类进入产卵和产卵栖息地。除了对洄游鱼类的影响外，湿地栖息地的丧失也可能对半水生海龟产生负面影响，例如布兰丁龟，它们在筑巢迁徙之前将沿海湿地作为觅食的集结地。该提案的主要目标是确定格鲁吉亚湾不同地区的鱼类和野生动物栖息地与水位之间的关系，包括南部地区，低水位与人类发展相混淆，北部地区主要不受人类活动的干扰，以及有或没有沿海湿地的岛屿。我将使用无线电发射机来确定北梭子鱼和muskellunge使用的产卵和育儿栖息地，并结合启用gps的无线电遥测和监视摄像机来确定布兰丁龟季节性使用的水生和陆地栖息地。这些信息将被纳入地理信息系统，并辅以水深和等高线数据，为每个物种建立生境适宜性模型。然后，我将量化整个格鲁吉亚湾代表性地点的关键栖息地的数量，作为不同水位情景的函数。第二个目标是了解筑堤作为一种可能的缓解措施的影响，以防止湿地干涸。

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.