Evaluating Fish Habitat Compensation in the Canadian Arctic: Stream Habitat Attributes and Macroinvertebrate Assemblages

• Author / Creator

  Erwin, Andrea Christine

• Resource development is expanding in Canada, particularly in the Arctic. In Canada, damage to stream ecosystems as a result of development requires habitat restoration or compensation measures. A compensation project, focused on improving ecosystem connectivity and aquatic habitat for fish within three small fish-bearing Barrenland lakes and their outlet streams, was conducted in the Lac de Gras, NWT watershed as a result of diamond mine development at Diavik Diamond Mine Inc. Habitat manipulations to the three outlet streams used two general fishway designs: gabion-style pool-weir and nature-like choke-pool structures. I used a Before-After-Control-Impact (BACI) design to assess stream habitat attributes, their ecosystem functions, and the macroinvertebrate assemblages before and after the compensation project. Many impacts resulted from the manipulations, but few were relevant to the long term ecological function of the system. The removal of riparian vegetation during manipulation construction best explains the reduction in stream organic matter, specifically course particulate organic matter (CPOM), observed at the gabion-weir treatment streams after manipulations. However, given the reasonable organic matter retention rates observed, CPOM can be expected to increase as vegetation reestablishes. For future compensation projects, it is recommended to take added measures to preserve and actively re-establish the riparian vegetation as much as possible during and after construction activities. There were many shifts in abundance of the macroinvertebrate assemblages for both treatments (fishway designs) in riffle and pool habitat, but no easily distinguished overall patterns emerged from ordinations, in part because shifts in at reference streams in riffle habitat also occurred. The observed decrease in Simuliidae at the gabion-weir treatment may be of concern as it is a potential food source for fish; however the affected stream was fishless. Although a reduction in some organic matter was observed at the gabion-weir treatment, and there were shifts in the macroinvertebrate assemblages, my research suggested that the compensation manipulations were largely successful in maintaining ecosystem structure and function, with some room for improvement.

• Subjects / Keywords

  • Arctic
  • Freshwater ecology
  • Fish Habitat
  • Macroinvertebrate
  • Compensation

• Graduation date

  Fall 2014

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3833N65G

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.