Linkages between climate, hydrology and ecology of lakes in northern thermokarst landscapes: past, present and future

气候变暖对加拿大北部水资源的影响是一个紧迫的问题，因为水在维护景观的生态完整性、经济发展和原住民社区的传统使用方面发挥着关键作用。这项拟议的研究将提高对老乌鸦平原(北育空)和哈德逊湾低地(北马尼托巴省)热喀斯特景观中的湖泊如何响应气候变化的理解。这两种景观在国际上都被认为具有重要的生态和文化意义，但湖泊和河流水文的变化挑战了各机构维持其自然资源完整性的能力，因为现有数据不足以制定有效的政策和做法。拟议的方案将整合3个研究部分，以提供足够范围的空间和时间(几年至几个世纪)的信息，以量化有影响的水文过程对热岩溶景观中湖泊生态条件的作用；包括：1)利用湖泊水、生物群和稳定同位素的空间调查，了解水文过程如何调节当代湖泊条件；2)利用保存在表层湖泊沉积物中并生长在实验底物站上的水生生物(藻类)的空间调查，发展从科学上可靠的能力，通过分析保存在沉积物岩芯中的生物群来解释生态水文变化；以及3)对过去千年选定湖泊的沉积物岩芯进行分析，以量化对过去水文变化的生态反应。这些热喀斯特地貌被认为非常容易受到全球变暖的影响，但它们的淡水生态系统在北美仍然是研究最少、了解最少的。因此，拟议的方案将提供对这些系统的基础研究，并促进北方各机构制定长期监测方法。它将提高政府机构(加拿大公园、Vuntut Gwitchin First Nation)履行有效管理景观的任务的能力，并将在热门的环境评估领域培训4名博士、2名硕士和10名本科生。

The impact of climate warming on water resources in northern Canada is a pressing concern, because water plays a key role in maintaining the ecological integrity of landscapes, economic development and traditional use by First Nations communities. The proposed research will improve understanding of how lakes in thermokarst landscapes of the Old Crow Flats (N. Yukon) and Hudson Bay Lowlands (N. Manitoba) respond to climatic changes. Both landscapes are recognized internationally as ecologically and culturally significant, but changes in lake and river hydrology challenge the ability of agencies to maintain integrity of their natural resources because existing data are insufficient to develop effective policies and practices. The proposed program will integrate 3 research components to provide information over a sufficient range of spatial and temporal (years to centuries) scales to quantify the roles of influential hydrological processes on ecological conditions of lakes in thermokarst landscapes; including: 1) use of spatial lake surveys of water, biota and stable isotopes to understand how hydrological processes regulate contemporary lake conditions; 2) use of spatial surveys of aquatic biota (algae) preserved in surficial lake sediments and which grow on experimental substrate stations to develop a scientifically robust ability to interpret eco-hydrological changes from analysis of biota preserved in sediment cores; and 3) analyses of sediment cores from selected lakes spanning the past millennium to quantify ecological responses to past hydrological changes. These thermokarst landscapes have been identified as very vulnerable to global warming, but their freshwater ecosystems remain the least studied and most poorly understood in North America. Thus, the proposed program will provide basic research on these systems and promote development of methodologies for long-term monitoring by agencies in the north. It will increase capacity of government agencies (Parks Canada, Vuntut Gwitchin First Nation) to fulfill their mandates to steward the landscapes effectively, and it will train 4 PhD, 2 MSc and 10 undergraduate research students in highly-sought fields of environmental assessment.