NWT RESEARCH DATABASE

Tags: physical sciences, aquatic ecosystems, biology, environmental monitoring, mining impacts, ecology, habitat enhancement, biological productivity

Objective(s): To study the freshwater ecology, hydrology, and hydraulics of small lakes and streams in the Lac de Gras basin before habitat modification; to monitor the changes in ecosystem productive capacity resulting from habitat modifications designed to increase habitat connectivity and fish passage; and 3) to assess the effectiveness of such habitat modifications through the use of a BACI (Before-After-Control-Impact) design.

Project Description: The objectives of this project are 1) to study the freshwater ecology, hydrology, and hydraulics of small lakes and streams in the Lac de Gras basin before habitat modification; 2) to monitor the changes in ecosystem productive capacity resulting from habitat modifications designed to increase habitat connectivity and fish passage; and 3) to assess the effectiveness of such habitat modifications through the use of a BACI (Before-After-Control-Impact) design. This research design allows for the assessment of post-construction impacts through a comparison with pristine reference conditions over the same before-and-after periods. Ground surveys, aerial photographs, and topographic maps will be used to assess stream geomorphology and substrate composition. The composition and amount of vegetation cover available for young-of-year (YOY) fish will be documented at each stream. Organic matter availability and production will be determined by counting instream woody debris and shrub stems, collecting drift with nets, and estimating vegetation coverage within 1 m of stream banks. In-stream vegetation assessments will be conducted once a summer in 40-m segments along reference and modified streams. Drift will be collected monthly. Stream gauges will be installed to monitor hydrologic conditions. Temperature loggers will be installed in each of the streams to be modified and at reference streams to determine degree-days during the season. Specific conductance, turbidity, and pH will be measure in situ, while water samples will be collected for total phosphorus, total nitrogen, and total suspended solids. Various techniques will be used to sample fish and invertebrate populations in the lakes and streams. Adult fish will be sampled with trap and gill nets and angling. Fish density and biomass in streams will be determined by electrofishing in mid-summer. Collected YOY fish will be measured for length and mass and their diet will be quantified. Sweep nets and Surber samplers will be used to collect invertebrates. Diavik Diamond Mines Inc. (DDMI) will hire an Aboriginal wildlife monitor from a local community for each of the four field seasons. These persons will part of an interdisciplinary team and will interact with professionals from academia, industry, and government. This dynamic and diverse work environment, alongside students and mentors, will facilitate social and cultural exchanges of ideas. The monitors will also have opportunities to communicate to their peers and communities about the issues relating to habitat compensation projects. Regular communications (email, teleconference, meetings) will be maintained throughout the project between the Research Team and DDMI, Golder Associates, and DFO. The research team will summarize their activities at an annual DFO-sponsored workshop in Yellowknife. The Research Team will also give a presentation at a meeting of EMAB (Environmental Monitoring Advisory Board) to discuss the status, results, and subsequent steps to be taken in the study. There will be opportunities for attendees to communicate their ideas and thoughts about the project to the aforementioned parties. Theses, peer-reviewed articles, and presentations given at conferences could be sent to interested groups and/or individuals. The fieldwork for this study will be conducted from June 1, 2011 to September 20, 2011.