Evaluating Fish Habitat Compensation in the Canadian Arctic: Stream Habitat Attributes and Macroinvertebrate Assemblages Andrea Erwin* 1, Abul Basar Baki 3, Christopher Cahill 1, Gregory Courtice 3,Kimberly Howland 1,2, Mark Hulsman 1, Brianne Lunn 1, Bill Tonn 1, David Zhu 3 1 University of Alberta, Dept. of Biological Sciences, 2 Fisheries and Oceans Canada, Freshwater Institute, 3 University of Alberta, Dept. of Civil and Environmental Engineering

Lac de Gras, NT Yellowknife, NT Photos Courtesy of Diavik Diamond Mines

M1S (50m) M3S (40m) M2S (27.5m) Lac de Gras M-Lakes Compensation Project Goal: Improve existing habitat for fish

Study Area – Manipulation and Reference Sites

R2S (103m) Lac de Gras Reference Sites R6S2 (177m) R6S1 (108m) Lac de Gras

 Improve ecosystem connectivity  Increase duration of continuous flow  Allow fish passage Compensation Project Objectives: M1SRef 6

Manipulations – Gabion-Weir Fishway (M1S & M3S) July 13, 2012 M-Lakes

Retrofitting of GW Fishways June 27, 2013

Manipulations – Nature-Like Fishway (M2S) May 31, 2012 M-Lakes

Compensation Evaluation Objectives Hydraulic characteristics – storage and discharge within M-Lakes and their outlet streams (Courtice et al. 2014). Fish attraction and passage efficiency of fishpasses (Cahill et al. 2015). Stream habitat attributes and their functions, and macroinvertebrate assemblages, before and after manipulations in relation to reference sites (Erwin et al. in prep.).

Physical stream characteristics – Stream morphology – Substrate Water chemistry – TN, TP, DO, pH, cond., temp. Biological attributes and stream function: – Riparian vegetation – Leaf litter processing rate – Course Particulate Organic Matter (CPOM) – Woody Debris – Debris retention Benthic macroinvertebrates – Abundance (total & ind. taxon) – Diversity

Experimental Design BEFOREAFTER Control Impact Baseline Data Compensation Assessment Habitat Manipulations Fall 2011/Fall 2012 BACI – Before-After Control-Impact (Underwood 1991) Reference 6 & 2 M1, 2, & 3

No Impact Impact BACI (Interaction) Effect Difference of changes in the two means (Control & Impact) between the Before and After periods – represents the potential environmental impact. *  = 0.10 (Not actual data!)

±1 Standard Error (variation around treatment-year means) Riparian Vegetation M1S After

Course Particulate Organic Matter (CPOM g/m 2 ) ±1 Standard Error (variation around treatment-year means) Pool Habitat p = 0.445

Instream Woody Debris (cm 3 /m 2 ) ±1 Standard Error (variation around treatment-year means) p = p = 0.117

Benthic Macroinvertebrate Sampling (benmeadows.com) Photo by Fred Noddin

Total Abundance (no./m 2 ) PoolRiffle p = 0.353p = p = 0.681p = 0.675

Diversity (H) PoolRiffle p = p = p = p = 0.359

Conclusion ↓ Riparian vegetation – both treatments ↓ CPOM – gabion-weir pool habitat No impact to: Instream woody debris CPOM – riffle habitat or nature-like pools Total Abundance Diversity From a habitat attribute perspective, fishway construction was largely successful.

Recommendations for Compensation in the Canadian Arctic: Using the BACI design has allowed us to account for temporal, spacial, and environmental variability (Underwood, 1992), and clearly show environmental changes resulting from fishway installations. Minimize disturbance by using manual construction methods and preserving as much riparian vegetation as possible. Enhance habitat not only for fish but for lower trophic levels, such as macroinvertebrates (increase primary productivity) (Roni et al 2008 ). Compensation should be assessed as an ecological experiment (Quigley and Harper, 2006). – Incorporate appropriate reference sites. – Assess projects before and after implementation.

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