Refining habitat indicators for Strategy 2 of the Wild Salmon Policy: identifying metrics and benchmarks

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Abstract

Canada’s Policy for Conservation of Wild Pacific Salmon (a.k.a. the Wild Salmon Policy, WSP) was released in June 2005 (DFO 2005). The overarching goal of the Policy is to restore and maintain healthy and diverse salmon populations and their habitats. To help evaluate whether the Wild Salmon Policy is succeeding in this regard Fisheries and Oceans Canada (DFO) intends to use “habitat indicators” to assess and monitor the status of and pressures on stream, lake, and estuarine habitats in British Columbia and Yukon (see Strategy 2 Assessment of habitat status and Action Step 2.2 Select indicators and develop benchmarks for habitat assessment of the Wild Salmon Policy).

Habitat indicators can track habitat conditions over time and identify salmon habitats that are most productive, limiting, or at most risk of disturbance within Conservation Units (CU).1 Indicators can also improve understanding of linkages among habitat pressures, habitat status, and management responses (e.g., conservation and restoration actions).

To-date, DFO’s process for developing habitat indicators has followed the following three steps:

Step 1: Indicator Compilation and Ranking: The first task required developing a list of habitat indicators for streams, lakes, and estuaries used by volunteer groups, DFO, and other government agencies in the U.S. and Canada. Drawing upon the work from other researchers in the Pacific Northwest, DFO’s Habitat Working Group (a group of managers and scientists) developed and ranked a preliminary list of habitat indicators based on the (i) number of other groups using / citing these indicators, and (ii) scientific relevance / strength of the linkage to key habitat attributes of interest.

Step 2: Indicator Practical Assessment: The second task involves assessing each indicator on the basis of a number of evaluation criteria (described further in Section 2): (i) data source, (ii) data availability, (iii) relative cost, (iv) spatial extent / resolution, (v) temporal extent / frequency, and (vi) scientific relevance (drawn from DFO’s efforts in Step 1). This information was then used to identify a suite of indicators that could potentially be implemented by DFO (summarized in Practical Assessment Report, pages 31-32, Tables 9 and 10 in Nelitz et al. 2007a).

Step 3: Indicator Metrics and Benchmarks: The third step requires identifying alternative ways of measuring an indicator, termed a metric (e.g., mean annual discharge vs. peak annual flow). Associated with alternative metrics are benchmarks, maximum tolerable thresholds or ranges within which managers wish to maintain habitat conditions (e.g., optimal water temperature ranges), or below which managers wish to minimize pressures on habitats so as to avoid adverse effects (e.g., thresholds for equivalent clearcut area).

This report provides results from Step 3, Identifying Metrics and Benchmarks for habitat indicators being considered by DFO for Strategy 2 of the Wild Salmon Policy.