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Scientists Outline Difficulties in Determining Restoration Strategies

by Bill Rudolph
NW Fishletter, April 15, 2003

Attendees at last week's meeting of the Power Planning Council heard about a new report from two members of the independent science panel who said it's going to be difficult to gauge habitat recovery plans because of a paucity of data needed to develop models that could be used to predict effects of certain actions. "At this point," said the scientists, "we don't know the 'best way' to determine restoration priorities."

Weyerhaeuser's Bob Bilby and Pete Bisson of the US Forest Service said that models like the EDT [Ecosystem Diagnosis and Treatment] approach that's being used extensively by the council in its subbasin planning efforts has "unknown predictive power" because it is based on expert opinions and not empirical modeling techniques that relate species abundance to habitat attributes

However, the lack of data hampers effectiveness of the statistically-based efforts as well, Bilby said. The SWAM [Salmon Watershed Assessment Method] model used by NMFS can explain only about 50 percent of salmon abundance at this time.

The scientists suggested that a combination of both kinds of models should be used to develop recovery plans. If both methods "point to the same locations and habitat conditions as being important factors limiting fish production, considerably more confidence can be placed in these conclusions."

Up to now, most restoration efforts have been evaluated at the reach scale, but the scientists said that to be most effective, restoration efforts must be evaluated at a scale large enough to enable complete freshwater rearing. And such an effort would not be cheap, the scientists said.

Bilby estimated that that the monitoring and evaluation effort should make up 25 percent to 30 percent of fish restoration costs, "decreasing on a sliding scale," he told the council last week.

"The expense and effort needed to obtain the data necessary for evaluating the response of salmonids to habitat restoration is considerable," said their report, "and this supports an approach of focusing intensive monitoring efforts on a relatively few locations. It is likely to require several fish generations to get statistically supported answers to questions about effectiveness of habitat restoration."

Bill Rudolph
Scientists Outline Difficulties in Determining Restoration Strategies
NW Fishletter, April 15, 2003

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