NWT RESEARCH DATABASE

Regions: North Slave Region

Tags: permafrost, fish habitat, climate change, fish health

Objective(s): To assess the impacts of climate change and wildfire on lake and fish health.

Project Description: This licence has been issued for the scientific research application No. 6165. To assess the impacts of climate change and wildfire on lake and fish health. Tli?cho Elders will identify two study lakes, each in either a burned or unburned catchment. Together with local land monitors, we will assess and compare abiotic (water quantity, quality, flow rate, and temperature, lakebed structure, dissolved oxygen, and light penetration) and biotic (ecosystem health at all trophic levels, regions of productivity) elements related to fish habitat, contextualized in lake history from sediment cores, to inform a 3D model of habitat in both lakes. The impacts of climate change and wildfire on lake and fish health will be assessed through: 1. Understanding the context: a. Through community meetings and focus groups, we seek to understand Tli?cho needs and re-shape project annually to support Tli?cho land use planning and stewardship, and territory-wide lake management planning. A community research coordinator/liaison will be hired to support engagement activities, help arrange personnel and resources and provide a line of communication between project partners. b. Use the physical, chemical and biological information preserved in sediment cores to establish how trophic conditions have changed in response to fires and reconstruct how key water-quality variables (nutrient and lake production) have changed over the lakes’ history. c. Quantify water and energy balances for each lake using field data (streamflow and groundwater, environmental tracers, precipitation, net radiation) and model each catchment with the Raven hydrological framework. All field data will be collected with Tli?cho Environmental monitors who will be trained in scientific methods, while providing key insights into site selection for measurements and sampling. 2. Establishing current conditions: a. Continuously measure lake water quality using novel osmotic samplers (nutrients, carbon, contaminants), augmented by grab samples of water inputs to each lake including groundwater in stilling wells, soil pore water using suction lysimeters, and water from surrounding wetlands, tributaries, and water bodies. b. Characterize microbial communities through genetic sequencing and asses functional potential of these communities in contaminant mobilization (e.g., mercury methylation). c. Characterise the year-round habitat occupancy and feeding by key subsistence fish species using acoustic telemetry and paired with food web stable isotope data. Fish samples will be collected with local environmental monitors following traditional harvesting practices, examining size, weight, flesh, and otolith. 3. Predicting the future: a. 3D numerical models of each lake, including inflows/outflows, atmospheric forcing, water circulation, water temperature, ice cover and water quality will be calibrated and validated against continuous measurements of lake parameters. b. Hydrologic and 3D lake models will be coupled to climate models as part of the National Water Quality Modelling Framework developed by Environment and Climate Change Canada. In collaboration with the Thermokarst Mapping Collective, led by the Northwest Territories Geological Survey (NTGS) and the Aurora Research Institute (ARI) , results will be contextualized in burned and unburned catchments across the NWT. The model will test the impacts of future climate change scenarios (including wildfire) on lake habitat to project future ecosystem health and extended to additional lakes across the territory to understand the potential large-scale impacts of wildfire on lake health. There are several decision-making partners who play critical roles in translating the proposed research findings to conservation impact at different scales and on different timelines in the project. Each partner and their roles are discussed below. At the most local scale, and on the short-term, the Whatì Community Government will work together with researchers to determine the impact of climate change and wildfire on lakes very near to their community. Given that the research questions stem from discussions with Whatì community members and this work is supported by the Whatì Community Council, research findings will be quickly transferred to local decision-makers. Environmental Monitors from Whatì (many who are on Council) will be instrumental in monitoring, fish harvesting, site selection, and providing local context for the findings. Based on our research findings, the Community Government will inform local land use and management strategies through the role of the Research Liason to mitigate for the ongoing impact of the 2014 wildfire. These will begin to be implemented within the timeframe of the project but will be continued indefinitely. In the long-term, the results will be upscaled with the help of the Tli?cho Government, who are uniquely positioned in the NWT to make conservation decisions unilaterally due to their settled land claim, and have developed the Tli?cho land use plan for this purpose. Strategies developed at the scale of the two proposed study lakes will augment existing monitoring programs and be implemented in lakes across Tli?cho territory. Research findings will serve to inform mitigation strategies for the impacts of wildfire through model scenario testing and improve understanding of areas where habitat is most affected. Such habitat can then be targeted for biodiversity conservation efforts. In addition, newly developed monitoring techniques will be incorporated into the Tli?cho Government-run TAEMP program to ensure continual learning from this research, and preservation of fish species for future generations. Once the Tli?cho partners and research team have established best management practices, these will be communicated to the Government of the Northwest Territories (GNWT) through both the Lands and Waters departments. Working with existing partners, we will support the development of monitoring programs, potentially staffed by community members trained through this project, that assess climate change resiliency of fish habitat. Through future research projects, we will construct numerical models of relevant lakes in the territory and inform decision-making and policy surrounding water stewardship in lakes subject to climate change and wildfire. Our government partners (Connon, Palmer, Kokelj) are interested in the implementation of many of the tools we propose, from the novel water quality monitoring techniques and fish tracking to model development and contextualization of current conditions from the lake sediment history. Finally, our research has potential to influence Federal Legislation through Fisheries and Oceans Canada (DFO) and Environment and Climate Change Canada (ECCC). Our research partners in both branches have ongoing work with our research team through the National Water Quality Modelling Framework, which is being applied to the Mackenzie River Basin. This productive and fruitful partnership has already informed fishery and water quality management decisions for the Laurentian Great Lakes and Lake Winnipeg, and there is interest in applying these collaborative monitoring and computer modelling techniques for improved management of Arctic aquatic ecosystems. Modelling efforts will support national climate change adaptation strategies, and the findings of this work will enumerate important techniques for adaptation and mitigation of climate change impacts on fish habitat, providing clear and incontrovertible evidence for the need for climate adaptation and management strategies at the national scale. The fieldwork for this study will be conducted from: June 01 - September 01, 2025