Impacts of climate change on wetland habitat for muskellunge and Blanding's turtles in eastern Georgian Bay

气候变化对乔治亚湾东部麝龟和布兰丁龟湿地栖息地的影响

• 批准号: RGPIN-2022-05289
• 负责人: ChowFraser, Patricia
• 金额: $ 2.91万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=745651
• 关键词: Impacts; climate; change; wetland; habitat

The coastal zone of Georgian Bay (GB), eastern arm of Lake Huron, has been designated by UNESCO as a Biosphere Reserve, where there are 50 species-at-risk including the federally endangered Blanding's turtle. Coastal marshes in eastern GB are used as spawning and nursery habitat by the muskellunge, the largest freshwater sportfish in Canada, and which grows to trophy status in GB and is unique among the Great Lakes in being a self-reproducing population. The greatest threat to coastal wetlands in this region is climate change, whose effects on coastal marshes have not been properly studied. First, there appears to be a change in the interannual fluctuations of water levels. Since 1918, cycles of fluctuations have ranged from 8 to 12 years; beginning in 1999, however, water levels remained near record low for 14 continuous years and then rose to above normal levels for the following 7 years. The terrestrial zone expanded greatly during the initial low-water years, with shrubs and 10-y old pine trees becoming established in former aquatic habitat. The new water-level regime also compressed the plant community and reduced fish species richness and diversity. When water levels abruptly increased in 2014, the trees and shrubs began to die but because of strong root systems, are still standing and have formed a novel "Dead Tree Zone". This novel zone has prevented re-establishment of submergent species that are required by age-0 muskellunge. A second effect of climate change is an increase in intensity and frequency of wildfires. We saw a preview of what's to come when the Parry Sound 33 fire consumed more than 110 km2 of land between Henvey Inlet and the French River during the summer of 2018. This fire burned almost all topsoil, leaving only bare rock in many places. This should have negative implications for Blanding's turtles that use lichen/moss on rocks as nesting substrate. The primary objectives of this proposal are to study the long-term effects of unprecedented water-level fluctuations and wildfire on habitat of Blanding's turtle and the muskellunge in coastal wetlands of Georgian Bay. First, we will conduct a change detection of vegetation zones in GB coastal marshes between the period of sustained low water levels and the recent 7 years of high water levels. We will then assess how these changes have affected the distribution and species composition of plants and fish (particularly muskellunge) in wetlands using a 15-y dataset. We have been tracking the Blanding's turtle in the Henvey Inlet/Key River region since 2020, and we propose to continue monitoring how Blanding's turtles use fire-affected vs unaffected habitat over the next 5 years. These long-term studies provide more appropriate data for assessing landscape-level changes in response to climate change, and inform conservationists how wetland plant structure will affect the long-term viability of the muskellunge and Blanding's turtle populations living in eastern Georgian Bay.

休伦湖东部乔治亚湾（GB）的沿海地区已被联合国教科文组织指定为生物圈保护区，其中有50种风险的物种，包括联邦濒临灭绝的布兰丁乌龟。东部GB的沿海沼泽被用作加拿大最大的淡水Sportfish的Muskellunge的产卵和苗圃栖息地，它在GB中的奖杯状态增长为奖杯，并且在大湖区在自我培养的人群中是独一无二的。对该地区沿海湿地的最大威胁是气候变化，其对沿海沼泽的影响尚未得到适当的研究。首先，水位的年际波动似乎发生了变化。自1918年以来，波动的循环范围从8到12年不等。然而，从1999年开始，连续14年的水位保持在创纪录的14年，然后在接下来的7年中升至正常水平。在最初的低水位年份，陆地区域大大扩展，灌木和10年的旧松树在以前的水生栖息地建立。新的水位制度还压缩了植物社区，并减少了鱼类的丰富性和多样性。当水位在2014年突然增加时，树木和灌木开始死亡，但由于根系强，仍在站立并形成了一种新颖的“死树区”。这个新颖的区域阻止了0岁Muskellunge所需的淹水物种重新建立。气候变化的第二个影响是野火强度和频率的增加。我们看到了一场预览，当时帕里声音33大火在2018年夏天在亨维·恩特（Henvey Inlet）和法国河之间消耗了110 km2的土地。这对Blanding的海龟具有负面影响，这些海龟在岩石上使用地衣/苔藓作为嵌套底物。该提案的主要目标是研究空前的水位波动和野火对布兰丁乌龟栖息地和佐治亚湾沿海湿地的栖息地的长期影响。首先，我们将在持续的水位持续时间和最近7年的高水位时期之间对GB沿海沼泽中的植被区进行变化检测。然后，我们将使用15-Y数据集评估这些变化如何影响湿地中植物和鱼类（尤其是Muskellunge）的分布和物种组成。自2020年以来，我们一直在跟踪Henvey入口/钥匙河地区的Blanding海龟，我们建议继续监视Blanding的乌龟如何在未来5年中使用受火影响与未受影响的栖息地。这些长期研究提供了更合适的数据，以评估响应气候变化的景观级别的变化，并为湿地植物结构如何影响Muskellunge和Blanding居住在乔治亚湾东部的乌龟种群的长期生存能力。