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.

休伦湖东部的乔治亚湾（GB）沿海地区已被联合国教科文组织指定为生物圈保护区，那里有50种濒危物种，包括联邦濒危的布兰丁龟。在GB东部的沿海沼泽地被用作产卵和苗圃栖息地的muskellunge，在加拿大最大的淡水游鱼，并增长到奖杯的地位，在GB和五大湖是一个自我繁殖的人口中是独一无二的。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有所变化。自1918年以来，波动周期为8至12年;但从1999年开始，水位连续14年保持在接近最低记录的水平，然后在随后的7年中上升到高于正常水平。在最初的低水年份，陆地区域大大扩展，灌木和10年的松树在以前的水生栖息地建立起来。新的水位状况还压缩了植物群落，减少了鱼类的丰富性和多样性。当水位在2014年突然上升时，树木和灌木开始死亡，但由于强大的根系，仍然站立，并形成了一个新的“死树区”。这一新的区域阻止了0岁muskellunge所需的淹没物种的重建。气候变化的第二个影响是野火的强度和频率增加。我们看到了2018年夏天帕里湾33号大火吞噬了亨维湾和法国河之间超过110平方公里土地的预览。这场大火几乎烧毁了所有的表土，在许多地方只留下光秃秃的岩石。这应该对使用岩石上的地衣/苔藓作为筑巢基质的布兰丁海龟有负面影响。该提案的主要目标是研究前所未有的水位波动和野火对格鲁吉亚湾沿海湿地布兰丁海龟和麝香龟栖息地的长期影响。首先，我们将进行GB海岸沼泽植被带的变化检测之间的持续低水位和近7年的高水位。然后，我们将评估这些变化如何影响植物和鱼类（特别是muskellunge）在湿地的分布和物种组成，使用15年的数据集。自2020年以来，我们一直在Henvey Inlet/Key River地区跟踪Blanding的海龟，我们建议在未来5年内继续监测Blanding的海龟如何使用受火灾影响的栖息地。这些长期的研究提供了更适当的数据，评估湿地水平的变化，以应对气候变化，并告知环保主义者湿地植物结构将如何影响长期生存的muskellunge和布兰丁的海龟种群生活在格鲁吉亚湾东部。