National Management Plan: An Action Plan for the Nation - Prevention

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[Executive Summary] | [Introduction] | [Survey of Federal Roles & Responsibilities] |
[An Action Plan for the Nation] | [Conclusion] | [Appendices]

Action Plan:
Leadership | Prevention | Detection | Control | Restoration |
International | Research | Info Management | Education

The first-line of defense and, over the long term, the most cost-effective strategy against invasive species is preventing them from becoming established. Prevention is two-pronged because some species are intentionally introduced for a specific purpose, whereas others arrive unintentionally as "hitchhikers" on a commodity, conveyance, or person.

Diverse tools and methods are needed to prevent invasive species from becoming established in ecosystems where they are not native. A risk-based approach is mandated by the Order, and requires consideration of the likelihood an invasive species will establish and spread, as well as the degree of harm it could cause.

Currently, a limited number of invasive species are listed as regulated species under Federal laws governing specific types of species such as noxious weeds, injurious fish or wildlife species, or aquatic nuisance species. These laws provide for public input and stakeholder involvement in the listing process.

At present, there are procedures for listing species that are known to be invasive. Such listings may be petitioned and involve stakeholders and the public in the course of the rulemaking process. Importation and interstate transport is prohibited for species that are Federally listed as noxious weeds or injurious wildlife. The adequacy of such listing procedures will be examined in the analysis of legal gaps, which is listed as an action item under Section B: Leadership and Coordination. Enforcement of prohibitions on listed species and exclusion of invasive species is largely dependent on inspection services at ports of entry.

For species that have not been listed, a key tool for prevention is a risk analysis and screening system for evaluating first-time intentional introductions of non-native species, before entry is allowed, and realistically applying similar principles or other management options for species currently in trade. In addition, a key priority will be identifying high-risk invasive species pathways and developing effective technologies and education programs to reduce the movement of invasive species through those pathways. Pathway management is the most efficient way to address unintentional introductions. Another line of attack is to identify high-risk invasive species not yet established, the likely pathways for their entry, and then management of the pathways to prevent introduction.

Preventing invasions requires more than analysis. Both appropriate regulation and voluntary codes of conduct are essential. Research is needed on the biology of invasive species and ecosystem vulnerability to them, and on means to detect and interdict invasive species that are en route to establishment. Finally, steps are needed to make sure the general public understands the harm that invasive species cause and the importance of preventing their introduction.

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Currently, one of the most effective means of excluding invasive insects, other animals, and plants is inspection of shipments at ports of entry. Port of entry inspection works in two ways, first by directly examining pathways for the presence of invasive species and second, by monitoring imports to insure that regulatory requirements for reducing the risk of introduction have been met. Both APHIS and FWS have relevant inspection services. Even though they have made an effort to focus on shipments from high-risk areas, they are unable to examine more than a small percentage of shipments entering the United States.

Action Planned

  1. As resources permit, APHIS and the FWS will dedicate additional human and financial resources to strengthening inspection services at ports of entry.

Intentional Introductions

The action items below call for the development of a risk-based screening process for intentionally introduced species in a series of steps or phases. During the first phase a screening system for first-time intentional introductions will be developed, with different agencies taking the lead as appropriate for the different types of species. The screening system will then be modified by those same lead agencies during the second phase to deal with species already moving in the U.S.

  1. By December 2003, the Council will develop a fair, feasible, and risk-based comprehensive screening system for evaluating first-time intentionally introduced non-native species (see items a-e below). To accomplish this task, appropriate Federal agencies will take the lead in developing and testing the screening system based on input from other Council members, ISAC, State governments, scientific and technical experts and societies, and other stakeholders -- including affected industries and environmental groups. The system will include recommendations regarding implementation issues, including: the scope of taxonomic coverage, the degree of initial screening coverage, and the role of appropriate regulatory and non-regulatory risk-reducing tools.

  2. By 2006, the same Federal agencies (as designated under a-e below) will develop modifications to the screening system or other comparable management measures (i.e., codes of conduct, pre-clearance or compliance agreements) to formulate a realistic and fair phase-in evaluation of those intentional introductions currently moving into the U.S., in consultation with ISAC, State governments, scientific and technical experts and societies, and other stakeholders, including affected industries and environmental groups.

Recommendations will be provided to the Council for the following screening processes:

a. Introduction of non-native biological control organisms for animal pest control within the continental U.S. to complement measures already in place for screening of plant biological control organisms. Lead Departments: USDA, Interior, and Environmental Protection Agency (EPA).

b. Introduction of all non-native freshwater or terrestrial organisms for any purpose into Hawaii, Puerto Rico, the U.S. Virgin Islands, or U.S. territories or possessions in the Pacific and the Caribbean (because of the vulnerability of insular areas, a separate screening process for those areas is needed). Lead Departments: USDA, Interior and EPA, the State of Hawaii, and the Governments of Puerto Rico and the Virgin Islands.

c. Introduction of non-native propagative plants or seeds for any purpose (e.g., horticulture or botanical gardens) within the continental United States. Lead Departments: USDA and Interior.

d. Introduction of non-native land animals for any purpose (e.g., insects, zoo animals, terrestrial pets, or food animals) within the continental United States. Lead Departments: USDA and Interior.

e. Introduction of non-native aquatic organisms for any purpose (e.g., fish or shellfish stocking, aquarium organisms, aquaculture stock, aquatic plants and biological control agents) within the continental United States. Lead Departments: USDA, Interior, and Commerce, EPA, and the Army Corps of Engineers.

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Unintentional Introductions

The most effective method of preventing the unintentional introduction of non-native species is to identify the pathways by which they are introduced and to develop environmentally sound methods to interdict introductions. Some pathways are already known to be significant sources of invasive species. For example, ballast water is probably the largest single source of non-native species introductions into coastal and estuarine waters. Solid wood packing materials are a source of serious forest pests. As a first step in dealing with unintentional introductions, Federal agencies should take steps to address pathways already known to be significant. In addition, it is important that other pathways be analyzed to determine their significance as a source of invasive species. The term "pathways" is also used in another context to describe the means by which an already established species may be spread to other areas. For example, the movement of aquatic species among watersheds is through interconnecting waterways and the weed seeds move in forage. Such pathways and action items to address them are covered under Section D, Control and Management.

Actions Planned

  1. Federal agencies will take the following steps to interdict pathways that are recognized as significant sources for the unintentional introduction of invasive species:

a. By July 2001, NOAA, the Coast Guard, Interior, and EPA will sponsor research to develop new technologies for ballast water management, because the current method of ballast water management--ballast water exchange--is recognized as only an interim measure to address non-native species introductions.

b. By January 2002, the U.S. Coast Guard will issue standards for approval of ballast water management technologies, because actual deployment of new ballast water technologies on ships is contingent on a standard by which to judge their efficacy.

c. By January 2002, USDA will issue additional regulations to further reduce the risk of species introductions via solid wood packing materials.

See Invasive Species Pathways Team Final Report(October 29, 2003)

  1. By January 2002, the Council will implement a process for identifying high priority invasive species that are likely to be introduced unintentionally, e.g., Mediterranean fruit fly and brown tree snake, and for which effective mitigation tools are needed.
    See Invasive Species Pathways Team Final Report(October 29, 2003)

  2. By June 2001, the Council will outline a plan for a campaign that will encourage U.S. travelers to voluntarily reduce the risk of spreading invasive species overseas. This project will seek to engage a diverse array of organizations related to aviation, travel and tourism.

  3. By December 2002, the Council, led by USDA, Defense, and Interior and in cooperation with the U.S. Agency for International Development (USAID), will develop a risk assessment program for the intentional and accidental introduction of non-native species through U.S. international assistance programs and encourage other countries and international organizations to do the same.

  4. By January 2003, the Council will implement a system for evaluating invasive species pathways and will issue a report identifying, describing in reasonable detail, and ranking those pathways that it believes are the most significant. The report will discuss the most useful tools, methods, and monitoring systems for identifying pathways, including emerging or changing pathways, and for intervening and stopping introductions most efficiently.
    See Invasive Species Pathways Team Final Report(October 29, 2003)

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Ballast Water Introductions of Nonindigenous Species

Ballast water is the water used by ships to provide stability and adjust a vessel's trim for optimal steering and propulsion. It is carried in ballast tanks that are distributed along the bottoms, tops, and sides of vessels. Ballast water often originates from ports and other coastal regions that are rich in planktonic organisms. Ballast water may be discharged as cargo is loaded or unloaded or when sea conditions change. The discharged water may contain myriad aquatic organisms from a wide range of taxonomic groups.

Currently, ballast water is probably the most significant pathway for the introduction of non-native species into coastal ecosystems. An estimated 50,000 commercial vessels enter the United States each year from overseas. A single vessel may carry more than 21 million gallons of ballast water. In 1991, the total volume of ballast water discharged into U.S. waters was estimated to be less than 79 million metric tons, most of which originated from foreign ports. With a typical transoceanic voyage duration of about 10-14 days, many of the organisms contained in ballast water survive the journey and are capable of invasion. For example, a large commercial vessel (such as a bulk carrier) arriving in the Chesapeake Bay from Europe will often carry millions of large planktonic organisms in their ballast water, and microorganisms occur in even greater abundance.

Historically, the transfer of organisms by ships has resulted in the unintentional introduction and establishment of hundreds of freshwater and marine non-native species into the United States. Ballast water was the likely pathway for the introduction of species such as the clam Potamocorbula amurensis into San Francisco Bay and zebra mussels and the fishhook water flea into the Great Lakes. Introduced dinoflagellates have contributed to harmful algal blooms in Australia, and recent studies have shown that ballast water may contain microbes that can cause human disease, including cholera. In recent years, the rate of new invasions in coastal ecosystems is apparently increasing, and most of this increase is attributed to shipping through a combination of ballast water discharge and hull fouling.

At present, ballast water exchange is the only management tool used routinely to reduce the risk of ballast-mediated invasion. Ballast water exchange involves replacing coastal water with open-ocean water during a voyage. This process reduces the density of coastal organisms in ballast tanks that may be able to invade a recipient port, replacing them with oceanic organisms with a lower probability of survival in near shore waters. There are two shortcomings with this procedure. First, the ability to safely conduct ballast water exchange depends upon weather and sea surface conditions; thus, it is not always possible to perform an exchange. Second, there is still some residual density of coastal organisms in ballast tanks following exchange, so this process is only partly effective. To address these shortcomings, additional ballast management practices (e.g., design and testing of shipboard technologies) are also being advanced as long-term strategies.

Ballast water management has been encouraged through a variety of national and international venues:

  • Ballast water exchange is recommended as a voluntary measure by the International Maritime Organization (IMO).
  • The Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 (P.L. 101-646) required that all vessels entering Great Lakes ports or the upper Hudson River from overseas undergo ballast exchange or some comparably effective ballast treatment.
  • The National Invasive Species Act (NISA) of 1996 (P.L. 104-332) reauthorized and amended the Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990. NISA requires mandatory ballast management reporting and voluntary ballast exchange guidelines for most vessels that enter U.S. waters. Recognizing that ballast water exchange is likely to be only an interim measure, the law also sets up a research program for the development of new technologies for ballast water management. Among technologies being evaluated are filtration, ozone injection, ultraviolet radiation, and chemical treatment.

Gregory Ruiz-Smithsonian Environmental Research Center

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