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，因为水在维持景观的生态完整性、经济发展和原住民社区的传统利用方面发挥着关键作用。拟议的研究将提高对老克罗平原（育空北部）和哈德逊湾低地（马尼托巴北部）热岩溶景观湖泊如何应对气候变化的理解。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对各机构保持自然资源完整性的能力提出了挑战，因为现有数据不足以制定有效的政策和做法。该计划将整合3个研究组成部分，提供足够范围的时空（年至世纪）尺度的信息，以量化热岩溶景观中有影响的水文过程对湖泊生态条件的作用；包括：1)利用空间湖泊水、生物群和稳定同位素调查来了解水文过程如何调节当代湖泊条件；2)利用表层湖泊沉积物中保存的水生生物群（藻类）的空间调查，通过对沉积物岩心中保存的生物群的分析，建立科学可靠的解释生态水文变化的能力；3)对过去一千年来选定湖泊的沉积物岩心进行分析，以量化对过去水文变化的生态响应。这些热岩溶景观已经被确定为非常容易受到全球变暖的影响，但它们的淡水生态系统仍然是北美研究最少、了解最多的。因此，拟议的方案将提供关于这些系统的基础研究，并促进发展由北方各机构进行长期监测的方法。它将提高政府机构（Parks Canada, Vuntut Gwitchin First Nation）履行其有效管理景观的职责的能力，并将在环境评估的热门领域培养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.