Purpose: To restore the natural balance of the region’s ecosystems by coordinating the removal of invasive species and revegetating publicly managed lands with native species.

The City of Portland sought to create a first-in-the-nation strategy for the management of invasive plant species through interdepartmental coordination and the establishment of citywide goals. Resolution 36360 directed all city bureaus to develop a three-year work plan to include invasive weed management as part of their regular operations, and was followed by a Resolution 36726 that adopted a management plan to achieve a set of 10-year goals. More recently, the Invasive Plant Policy Review and Regulatory Improvement Project was adopted under Ordinance 183534 in an effort to strengthen and unify invasive management policy.

The Bureau of Environmental Services is leading this aggressive approach to an issue that was formerly addressed by disjointed efforts at various bureaus. The resulting strategy seeks to contain, control and eradicate invasive species on approximately 4,000 acres (40%) of publicly managed land by 2020. The City also requires removal of the most-damaging species on privately owned property. Private property owners are restricted from planting nuisance species that could become a threat in the future. All efforts to address invasive plant species are guided by ranked lists of threatening species.

After drafting the Portland Invasive Plant Management Strategy, public comments were collected during a one-month stakeholder review period. The resolution to adopt the strategy enjoyed the support of many agencies and organizations, including the Oregon Invasive Species Council and the Oregon Association of Nurseries. An Invasive Species Summit was held for over 200 attendees to inform stakeholders of the policy details. All three policies were unanimously adopted the City Council and/or Planning Commission.

There are currently 15 species on the Eradication List. Excluding wildfire risk reduction efforts, invasive plants were removed from over 1800 acres during FY 2009-2010. Monitoring of potential threats and maintenance on previously cleared land was also conducted on over 2,500 acres during FY 2009-2010.

It is anticipated that the 10-year goals will achieve root systems, groundcover and forest canopies appropriate for Portland’s climate, which will improve habitat on 66% of the city’s open space. These accomplishments will reduce the negative consequences of storm events, regulate stream temperature, improve water quality, restore watershed health and protect the existing green infrastructure. By 2020, the City expects to convert
• 1,947 acres from “good” to “healthy” status,
• 1,871 acres from “fair” to “good” status,
• 833 acres from “poor” to fair” status, and
• 153 acres from “severely degraded” to “stable” status.

The total cost of implementing invasive plant species controls will vary widely from city-to-city, and is largely dependant on the extent that nuisance species are established. The programs administered under Portland’s Invasive Species Management Plan are funded primarily through ratepayer sewage fees. Benefits to watershed health, increased salmon protections and reduction of wildfire risks allow for additional invasive removal and revegetation program funding. The programs robust funding sources allow for proactive control efforts, which are most cost-effective. US Congress estimates that $1 spent on early detection, control and eradication prevents $17 of potential future damage. The Oregon Department of Agriculture estimates that, within the state, $1 prevents $34 of potential future damage.

Complete eradication of invasives on Portland’s land would cost $12,000 an acre for a 5-year span. This would translate to $50-154 million to totally eradicate and revegetate, without accounting for staff time. The majority of the expertise needed to administer Portland’s plan came from existing employees. Contracting AmeriCorps participants and establishing partnerships with volunteer organizations will be utilized to reduce overall costs.