Evaluating Fish Response to Habitat Restoration

1
Evaluating Fish Response to Habitat Restoration

• Overview of Intensively Monitored Watershed
  Research in the PNW

• Rationale for IMW approach
• Extent of current efforts
• Example of results from an IMW effort
• Fish Creek (Dr. Gordon Reeves)

2
Issue Being Addressed

• Many millions of have been spent in the PNW
  on salmon habitat restoration and protection
• Expectation that these actions will increase the
  productivity of fish populations
• Little direct evidence that these efforts have
  been effective
• This knowledge is essential to
• Effectively allocate restoration resources
• Estimate the contribution to recovery of
  tributary habitat actions

3
Relationship between Freshwater Habitat Condition
and Salmon Productivity

• Relationship is difficult to quantify
• Variability in fish populations due to factors
  other than freshwater habitat
• Year-to-year variation in climate
• Data on fish populations is lacking
• Each species requires a suite of habitat types to
  complete freshwater life rearing
• The relative importance of each type of habitat
  varies spatially and temporally

4
IMW Concept

• IMW approach based on the premise that
  watershed-scale experiments are an effective
  means to study salmon-habitat relationships
• Quantification of salmon response to habitat
  actions requires assessment at appropriate scales
  of space and time
• Experimental unit large enough to include all the
  habitats required for freshwater rearing
• Unit small enough so a high proportion of the
  habitat can be treated
• Evaluation over sufficient time to be able to
  detect a response
• Expense requires that IMWs occur at relatively
  few locations
• Various designs have been employed
• Long-term, paired-watershed experiments
• BACI design
• Single watershed quantify ecological processes
• Most IMWs collect data on a basic set of
  parameters
• Habitat (physical, chemical)
• Fish populations (fry, parr, smolts, adults)

5
Scientific Support for the Concept

• Number of regional science panels have
  recommended this type of approach
• NOAA Fisheries SRSP - grand experiments
• ISAB/ISRP- intensive watershed monitoring
  advocated in numerous reports
• Monitoring design for WA forest practices
  identified IMW as a component of effectiveness
  monitoring
• WA ISP has reviewed the WA IMW program twice and
  concurred with the approach

6
WA IMW Lower Columbia Study Sites
7
Location of Some Current IMWs
8
Issues Raised about IMWs

• Time required to detect a response
• Long studies traditionally required owing to
  interannual variation in salmon abundance and
  climate
• Difficult to obtain consistent funding for
  long-term studies
• Transferability of results
• Are results of an IMW study only applicable to
  the watersheds where the studies were conducted?

9
Time to Detect Results
WA IMW - Seabeck Creek p0.05
10
Transferability of Results

• Large number of watershed-scale manipulative
  studies established in last 5 years
• Increased sample size (comparable questions and
  data collection methods)
• Comparison of results will provide indication of
  generality
• Expect like responses from watersheds with
  comparable conditions
• Classification of watersheds across the region
  being conducted by NOAA-Fisheries
• IMWs provide understanding of processes governing
  relationships between habitat and fish population
  response
• Many of these relationships will be broadly
  applicable
• Greatly improve our ability to parameterize
  predictive models currently in use
• IMWs will help to identify habitat parameters
  most relevant to fish
• Useful in gauging watershed condition regionally
• Provides direct linkage between the IMW efforts
  and status and trend monitoring being conducted
  at broader scale