CORVALLIS, Ore. – A new report prepared for the Oregon Invasive Species Council concludes that the state needs to more strongly consider the economic consequences of addressing invasive species and not just focus attention on the biology and ecology.

Written by Chris Cusack and Michael Harte of Oregon State University, the report says economics “provides us with many of the tools we need to understand and tackle the invasive species problem.”

“Invasive species already cost Oregon hundreds of millions of dollars each year in lost agricultural production and control, yet we still tend to think of them as biological issues, not economic ones,” said Harte, who directs the Marine Resource Management Program at OSU. “Over the next 20 years, the economic impact of invasive species will be as big, if not bigger in Oregon than the impacts of global warming.

“Not until we make that shift in people’s minds will we get traction on the issue and begin more serious efforts at prevention,” Harte added.

The authors say the best general estimate for direct and indirect impacts of invasive species nationally is about $140 billion a year. Although no total figure is available for Oregon, estimates for some invasive species control projects include:

• $120 million a year for 21 species of noxious weeds, resulting in agricultural production losses, fire damage and control costs;

• $7 million a year to control the outbreak of Sudden Oak Death – a total which could jump to $79 million to $304 million annually through nursery production losses if the disease becomes established;

• $25 million a year maintain 13 hydropower facilities if zebra mussels gain a foothold in Oregon waterways;

• $10 million to $31 million a year to remove invasive plants from Portland and replace them with native species over a five-year period;

• $6 million in 2006-07 to eradicate an illegally introduced fish (Tui Chub) responsible for food chain impacts that led to dangerous levels of toxic cyanobacteria blooms in Diamond Lake;

• $22.7 million invested by the Oregon Watershed Enhancement Board on invasive species projects since 1999. A portion of this investment went to restoration projects after control of the invasive species.

These estimates don’t even begin to address less measurable economic costs related to invasive species, Harte pointed out. The Australasian burrowing isopod has been discovered in both Coos Bay and Newport’s Yaquina Bay – and billions of burrows created by this invader “made Swiss cheese of estuarine shorelines, leading to massive erosion and loss of pasture and wildlife habitat.”

“There also is a cost to human health associated with invasive species, such as the Asimminea parasitological snail, which is the primary intermediate host for human lung flukes discovered last year in Coos Bay,” said Sam Chan, an invasive species specialist and educator with the Oregon Sea Grant program at OSU.

Another example was the E-coli epidemic in 2006 associated with eating raw spinach that was linked to contamination by feral pigs roaming the fields.

“It can be very hard to put a dollar figure on things like that,” Harte pointed out.

Sudden Oak Death provides a good case study for the economic impacts of invasive species, the authors say. The disease was first reported in Oregon in 2001, and the state began an intensive program to eradicate it by cutting and burning host plants. This invasive pathogen kills not only oaks, but rhododendrons and horticultural plants and is a major threat to southwestern Oregon timber sales should it spread.

Despite the eradication efforts, Sudden Oak Death has continued to appear in new locations in Oregon and earlier this year, the quarantine area in Curry County was increased to 162 square miles, Harte said.

The early detection and eradication program has cost Oregon about $1.8 million a year and the complete cost of eradication is estimated at $7 million annually over the next five years. But Sudden Oak Death could devastate nurseries and timber harvests because of potential quarantine requirements costing Oregon hundreds of millions of dollars in lost revenues each year.

“You don’t need to be an economist to figure out that $7 million now is nothing compared to the potential costs of this invasive disease if we don’t spend money now on eradication,” Harte said.

Thinking about invasive species in economic terms leads to a different set of strategies and implications, Harte pointed out.

“For a start, we begin to realize locally and for the foreseeable future the impacts of invasive species are on par with those of global warming,” Harte said. “Oregon and Oregonians can’t necessarily stop global warming by ourselves, but we can stop invasive species.”

Prevention, education, vigilance and a common approach to understanding the economics of invasive species is necessary, the authors point out, yet success will depend on consistency. They write: “Three ports on the west coast may have best practice invasive species prevention measures in place, but a fourth port may only put in place the minimum prevention practices required by law. This ‘weakest link’ can result in (invasive species) introductions into the region despite the very best effort of the other three ports.”

Harte says that compared with many countries, the United States has been slow to address the invasive species problem. His native New Zealand, in contrast, allots about 1 percent of all government spending to tackle invasive species issues.

“I’ve had people ask me why Oregon needs to spend so much on invasive species when they’re not even here yet,” Harte said with a laugh. “My grandmother was always quick with the cod liver oil, saying an ounce of prevention was better than a pound of cure. The same goes for invasive species – the ounce of prevention pales in comparison to their potential economic impact if they become established.”

Chan says Oregonians aren’t clear about which species are problems – and what to do about it. A recent focus group study by one of Chan’s graduate students, Gwenn Kubeck, found that Oregonians participating in the study felt a lack of institutional support to prevent invasive species, and without support from institutions, personal behavior changes have no real efficacy.

“Increasing this institutional support will likely require a reallocation or increase in resources,” Chan said.

Chan, along with Oregon Sea Grant colleagues Lynn Dierking, a professor of free choice learning, and Joseph Cone, assistant director of Oregon Sea Grant, reported early findings from a 2008 survey that 79 percent of Oregonians had heard of invasive species in a general sense and expressed concern. But few could describe the threat of invasive species such as quagga mussels, feral pigs or yellow-flag iris.

The survey also showed that 65 percent thought the most serious outcome associated with non-native plants and animals in Oregon was harm to native plants and wildlife.

“That underscores the need to look at invasive species through an economic lens as well as a biological one,” Chan said.

Harte said the goal of the report to the Oregon Invasive Species Council was not to provide a comprehensive outline of Oregon’s invasive species problem, nor to provide a precise dollar figure for addressing each issue. But looking at invasive species through an economic perspective, he added, is long overdue.

“The figures are dramatic,” Harte said, “but even these are only a partial estimate. They don’t account for the potential loss of tourism, lost fishing opportunities, the degradation of habitat or the myriad offshoots that invasive species may engender.”

The report is available from Michael Harte by e-mailing him at


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Michael Harte,