FO: NAFC/2000/8(b)


 

NORTH AMERICAN FOREST COMMISSION

Item 6(b) of the Provisional Agenda

TWENTIETH SESSION

St. Andrews, New Brunswick, Canada,
12-16 June 2000

ALIEN SPECIES HARMFUL TO NORTH AMERICAN FORESTS

 

INTRODUCTION

1. The spread of non-indigenous or alien forest pests1 is a growing threat to North American forests, its international trade in forest and other products, and communities dependent on healthy forests and forest industries. The spread of invasive organisms, including alien forest pests, is increasingly recognized as a global issue that has wide implications for biodiversity, ecosystem health, human health, natural resource industries, and international trade. The paper outlines current alien forest pest issues and concerns in Canada, United States and Mexico, and measures taken or needed to address current and projected threats from these organisms. Lastly, some possible implications that the Commission might consider on this matter are included.

WHAT ARE ALIEN SPECIES HARMFUL TO NORTH AMERICAN FOREST?

2. Alien species are, with respect to a particular ecosystem, any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to that ecosystem.2 When they cause changes in ecosystems, displacing native organisms by predation or parasitism, by competition for space and nutrients or food, or by alteration of habitats, alien species are considered to be invasive. When their impacts are beyond acceptable levels, resulting in environmental damage and economic and social losses, alien species become known as pests. In a more narrow classification, the 1997 revised text of the International Plant Protection Convention (IPPC) defines a quarantine pest as "a pest of potential economic importance to the area endangered thereby and not yet present there, or present but not widely distributed and being officially controlled." Discussions continue in several fora, including the International Convention on Biological Diversity (CBD) and IPPC to develop common terminology.

3. North American forests are particularly vulnerable to invasions of European and Asian insects, which often out-compete their North American counterparts, especially in disturbed and fragmented forests. More than 300 species of tree-feeding insects from Europe have successfully invaded North America, compared with only 34 that have made the reverse journey.1 What most of these invasive species share, besides not having natural checks to their survival and spread, is that they are generalists: they reproduce quickly, disperse widely when given the chance, tolerate a fairly broad range of habitat conditions, and resist eradication once they are established.

4. While humans can depend heavily upon introduced organisms for food, shelter, medicine, ecosystem services, aesthetic enjoyment and cultural identity,3 intentional introductions that are beneficial in specific areas, for some sectors of society and at given times, can turn out to be costly. Some 85% of industrial forestry plantations are established with species of just three genera - Eucalyptus, Pinus, and Tectona.4 Examples include the escape of plantation trees into watersheds in water-short areas of South Africa5 or into conservation areas in New Zealand. Thousands of vascular plant species have been introduced into North America since early settlement, many of which are considered weeds. Examples of plants intentionally introduced into North America include several ornamentals. Purple loosestrife, Lythrum salicaria L., threatens natural ecosystems in eastern areas of the continent. Common along both the Atlantic and the Pacific coasts of North America, two related invasive weeds, Scotch broom, Cytisus scoparius (L.) Link and gorse, Ulex europaeus L., are hindering the regeneration of commercial forest tree species such as Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco var. menziesii, and encroaching on stands of Garry oak, Quercus garryana Dougl., in British Columbia (Peterson and Prasad 1998). Another example is the explosive invasion across south Florida of the melaleuca or paper bark tree, Melaleuca quinquenervia, native to Australia and originally introduced into South Florida as ornamentals, which has the potential to invade all of that region's wetlands within the next 50 years.6

5. More research is needed to ensure that the same will not happen with genetically modified plantation stock. The International Union of Forest Research Organizations (IUFRO) Working Party on Molecular Biology of Forest Trees hopes its September 1999 position statement will help to bring sound science to bear on this discussion as it plays out within forestry, and will stimulate further research to ensure that the vast potential for genomic engineering of forest plantations does not go untapped.7 The FAO has issued a general statement on the application of biotechnology in agriculture, fisheries and forestry, as well as the food industry.8

6. The accidental introductions of harmful alien species have had devastating effects on the health, loss of biodiversity and endangered species, and reduction in timber and other values of North America's forests. Quantification of damage and increased control costs is difficult. Losses caused by alien forest pests in the United States are estimated to exceed $4 billion per year.9

WHY IS INVASIVE ALIEN FOREST SPECIES SUCH A LARGE ISSUE NOW?

Increased detections at North American ports

7. In the past century, alien pests have become established in North America with devastating effects on forest health, biodiversity, and timber and other forest resource values. Chestnut blight, Cryophonectria parasitica (Murr.) Barr10 and Dutch elm disease, Ophiostoma ulmi (Buisman) Nannf., have had such a devastating effect that the host species, American chestnut, Castanea dentata (Marsh.) Borkh., and American elm, Ulmus spp., respectively, have ceased to be a significant part of the deciduous forests of southeastern North America. They exist only as "ghost" trees, and ecosystems in the region now contain a different mixture of species. Beech bark disease, Nectria coccinea (Pers.:Fr.) F. var. faginata Lohm., Wats. & Ayers, with beech scale, Cryptococcus fagisuga Lind., and balsam woolly adelgid, Adelges piceae (Ratz.), reduce the value of the wood in infected trees. White pine blister rust, Cronartium ribicola J.C. Fisch., along with the native white pine weevil, Pissodes strobi (Peck), has greatly reduced the commercial value of planting white pine, Pinus strobus L, and P. monticola Dougl. ex D. Don, and threatens ecologically important species such whitebark pine, Pinus albicaulis Engelm.

8. The spread of harmful alien organisms has recently become a pressing issue regionally and globally because more pests are being detected at our ports, ship and shipping technology is changing, and our forests are perhaps becoming more susceptible to the establishment and spread of harmful invasive alien organisms. The increased detections of foreign forest pests result mainly from the use of shipping containers, direct point-to-point delivery of shipments, the increase in the volume of trade, and a broadening of trading partners, especially with the Pacific Rim and Asia. Trade volume is so large that most countries can manage to inspect only 1% to 2% of shipments. Rates of inspection can be higher for targeted commodities from certain countries of origin.

9. Destructive alien insects threatening North American forests include the European and Asian races of gypsy moth, Lymantria dispar(L), the Siberian moth, Dendrolimus sibiricus Tschetwerikov, pine shoot beetle, Tomicus piniperda (L), and a Eurasian spruce bark beetle, Ips typographus L, the Asian long-horned beetle, Anoplophora glabripennis (Mots), and the hemlock wooly adelgid, Adelges tsugae.11Tree diseases are less obvious but also serious threats to North American forests. Several that have been expanding their ranges are pitch canker, caused by Fusarium subglutinans F. sp. Pini).12 Beech bark disease, Butternut canker, Sirococcus clavignenti-juglandacearum Nair, Kostichka & Kuntz, and European larch canker, Lachnellula willkommii (R. Hartig) Dennis.13 There is usually a lag of several years between the introduction of tree diseases and their detection in the forest.

10. The Asian long-horned beetle, a new arrival to North America, is already costing millions of dollars in a campaign to eradicate infested trees from entire city blocks. These insects have been detected in wooden packing materials including wire spools, crates, pallets, and props, referred to as dunnage, in shipments of a wide variety of products such as wire rope, machinery, and stone. As a result of recent Asian long-horned beetle introductions into the United States and an increase in interceptions in both Canada and the United States, both countries implemented new plant health import requirements. As of January 4, 1999, all solid wood cargo crating from China and Hong Kong must be heat- or chemically treated to prevent further introductions of these pests.14

11. There have been several interceptions by Mexico of quarantinable forest pests such as wood borers of the genera Minthea, Sinoxylon, Dysides and Heterobostrychus in forest products (sawn wood, furniture, etc.) imported from South America and Asia. In addition, damage likely caused by Anoplophora glabripennis has been detected in wooden packaging materials accompanying products from China. This has resulted in stricter national regulations and improved inspection systems for these products at authorized points of entry.

12. The Forestry Panel of the North America Plant Protection Organization (NAPPO), with the advice of the NAFC Forest Insect and Disease Study Group (NAFC/IDSG), recently finalized a standard on dunnage. Once implemented, all foreign wood packing material and dunnage must be treated to prevent the introduction of harmful alien pests such as the Asian long-horned beetles and other foreign pests from entering North America. Similar restrictions have also been put in place by other countries, including the United Kingdom, China, Chile and Brazil.

13. Under the Montreal Protocol, an international agreement on ozone-depleting substances, the use of methyl bromide as a pesticide by developed countries must be phased out by 2005. Methyl bromide may still be used for quarantine purposes but pressure could mount as this date approaches to discontinue its use even as a fumigant. Replacement products would then be needed to reduce the risk of alien pest introductions.

14. Dunnage regulations are precedent-setting in that they are a departure from the more common pest- or commodity-specific quarantine rules. The new regulations recognize the importance of a pathway, which is inherent in the movement of goods. Pathways for introductions and spread of harmful alien pests also include soil and foliage of horticultural stock, soil on containers and used machinery, and disease-causing fungal spores and plant seeds in used machinery and parts. It is increasingly recognized that dunnage and ballast water are not the only pathways for the spread of harmful invasive organisms around the world. Moreover, because the problem is global, any individual country can be both the source and recipient of harmful alien species.

15. The gypsy moth is a long-standing example of an organism for which North American countries can be both a source and recipient. Furthermore, such organisms can be the source of tension between two neighboring countries. A European race of the gypsy moth was first introduced into the eastern United States in 1868 and later into Ontario and Quebec. Though not established in British Columbia, repeated introductions in the province over the past 20 years have required continued monitoring, eradication programs, and public awareness.15 In 1998, partly because of concern from the neighboring US states over the spread of this pest, and its more dangerous relative, the Asian gypsy moth, southern Vancouver Island was included in a quarantine zone. This involved certification and inspection of shipments and all vehicular traffic from this region. These measures, combined with eradication programs, may contain the moth in this area and possibly eliminate it.

16. The case of the pinewood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle, is an example of phytosanitary regulations may be used as non-tariff barriers. The pinewood nematode is a microscopic organism that causes pine wilt disease resulting in economic damage to pines in Japan and China. The organism is also present in North America, where it does not cause any economic damage to the native conifer forest.16 European Community countries imposed plant health regulations on shipments of green lumber from North America even though there was no proof that the presence of pinewood nematode on Canadian and US lumber shipments would lead to pine mortality in European forests. As a result of the regulation, lumber industries in both countries lost hundreds of millions of dollars in sales to Europe.

International biodiversity agreements and programmes

17. The spread of alien organisms is being acknowledged as a global concern in several international fora. The scope of the issue is beyond the capacity of any one country to manage, and requires scientific collaboration. Article 8h of the United Nations Convention on Biological Diversity (CBD) prescribes that signatories should, as far as possible, prevent impacts of alien species and develop national strategies, plans, or programs to this end. The issue of invasive alien organisms is on the agenda of the parties of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and is also addressed in the Montreal Process framework of criteria and indicators for the conservation and sustainable management of temperate and boreal forests.18

18. No global strategy yet exists to address the invasive species problem. To rectify this, the Conference of the Parties (COP) of the CBD fostered an initiative to establish the Global Invasive Species Program (GISP),19 a component of an international program on the science of biodiversity, DIVERSITAS. GISP will compile and make available the best management approaches for pest prevention and control; assess the current status of the science dealing with invasive species, and lay the groundwork for new tools in science, information management, education, and policy that must be developed through collaborative international action. GISP is also working with the Convention secretariat to develop guiding principles for the prevention, introduction and mitigation of impacts of alien species, which will be considered at the Fifth Meeting of the COP/CBD.20

International trade

19. The International Plant Protection Convention (IPPC) is a multilateral treaty under the auspices of the Food and Agriculture Organization of the United Nations (FAO). The purpose of the IPPC is to secure common and effective action to prevent the spread and introduction of pests of plants and plant products and to promote measures for their control. The Convention provides a framework and forum for international cooperation, harmonization and technical exchange in collaboration with regional and national plant protection organizations (RPPOs and NPPOs). The IPPC plays a vital role in trade as it is the organization recognized by the World Trade Organization in the Agreement on the Application of Sanitary and Phytosanitary Measures (the SPS Agreement) as the source for international standards for the phytosanitary measures (ISPMs) affecting trade.21 NAPPO has a similar role in North America, and is recognized as the authority on phytosanitary issues under the North America Free Trade Agreement (NAFTA).22 The NAFC/IDSG has successfully served as an advisory body to NAPPO since 1995.

20. Information-sharing is central to the functioning of these related institutions. Despite the need for information sharing and cooperation to slow the spread of invasive organisms, it is also well recognized that sharing pest information may be difficult where trade disputes exist or could develop.

21. The WTO-SPS Agreement and the Revised IPPC, although not yet widely ratified, ensure that there are structured channels for notification of changes to phytosanitary measures, deviations in the relevant regulations, and a forum for information sharing. The primary responsibility on information sharing lies with each individual country member.23 The IPPC Secretariat promotes and facilitates information sharing in a variety of ways. The official FAO Plant & Pest Information System (GPPIS) is the preferred information system for the IPPC Secretariat. The North American Forest Commission's Exotic Forest Pest Information System for North America (EFPISNA) is one of these databases.24 This list, initiated in 1995 and launched on the World Wide Web in 1998, provides, inter alia, a basis to the Commission for targeting organisms for further study and action. Both EFPISNA and GPPIS are under development. While GPPIS covers all plant pests, EFPISNA deals only with forest pests. EPPISNA contains 17 records now with records of up to 200 additional pests under development. Unlike GPPIS, EFPISNA includes risk analysis and mitigation measures. Furthermore, EFPISNA is intended to serve as an information source for NAFC member country with programs concerned with operations, surveys, research, and quarantine. The information in the EFPISNA is science based and not limited by international agreements, policies or regulations. It is not as a quarantine list. NAFTA's Commission for Environmental Cooperation (CEC) has established the Conservation of Biodiversity Program, whose work plan includes the issue of invasive species.25 Considering NAPPO's and NAFC's roles as centers of expertise and information for bodies implementing WTO-SPS and NAFTA, collaboration seems desirable to close information gaps.

22. At the international level, Mexico has been participating since 1998 in the analysis and exchange of technical information on forest pests of significance in the Central American region at meetings of the Regional International Organization for Plant Protection and Animal Health (OIRSA).

23. The trend is towards convergence of international bodies focusing on purely trade/ quarantine matters and those devoted to broader biodiversity/ecosystem health concerns. For instance, at the meeting last year of the Second Interim Commission on Phytosanitary Measures (ICPM), it was decided inter alia that an exploratory open ended working group would address the issues of genetically modified organisms (GMOs), biosafety and invasive species in relation to IPPC. Among its terms of reference, this working group is to "Develop a statement on: ...(ii) the relationship between invasive species and plant quarantine pests."26 It is likely the working group or ICPM secretariat will contact the CBD and NAFC secretariats on this matter. Common areas of interest include terminology, guiding principles such as those being discussed by the Subsidiary Body on Scientific, Technical and Technological Advice to (SBSTTA) the COP/CBD, and information sharing mechanisms.

CONCLUSIONS

24. There is no doubt that the problem exists and is likely to get worse, and that concerted efforts will be needed to deal with alien forest pests. Unfortunately, there are no easy answers because this issue is about responding to risks that are extremely difficult to anticipate, define or assess with any degree of certainty. Impacts of alien pests are both short-term and long-term. In the short term, there is a need for prevention of entry and spread, including eradication techniques, for early detection, and timely and reliable risk assessments. Early detection is essential to prevent entry and spread; too often, new introductions are discovered too late for effective eradication. Furthermore, these measures need to go beyond specific pests or commodities and deal with common pathways for wide variety of alien organisms. In the longer term, the impact on forest ecosystems - its composition, processes and resiliency - as well as timber losses, need to be addressed. Social and economic impacts are both long and short term. When potentially dangerous pests are identified in risk assessments, and faced with associated high degrees of scientific uncertainty, decisions-makers have recourse to the precautionary principle, first recognized internationally in World Charter for Nature, adopted by the UN General Assembly in 1982 and enshrined in the 1992 Rio Declaration as principle 15:

"In order to protect the environment, the precautionary approach shall be widely applied by States according to their capability. Where there are threats of serious or irreversible damage, lack of full scientific certainty will not be used as a reason for postponing cost-effective measures to prevent environmental degradation."27
The precautionary principle is explicitly or implicitly recognized in national and international trade, health and environmental frameworks, including article 5(7) of the WTO-SPS Agreement, the preamble of the CBD, and most recently, in the Protocol on Biosafety. However, the issue of how and when to apply the principle is giving rise to much debate.28

25. Commission's members have agencies addressing various aspects of harmful alien species that are invading forests. Further, in all three countries, national forest services collaborate closely with quarantine regulatory agencies. The science side of the collaboration contribute to the provision of an early warning system - better ways to anticipate and detect new introductions and to predict their potential spread and biological behavior; improved risk assessments - both from a biological and socio-economic perspective; more effective ways to prevent entry and spread of harmful alien species; and, when these measures fail, ways to manage these organisms. In addition, regulatory policies and programs, including mechanisms, are needed to deal with pest pathways and intra-national spread of alien forest pests. However, it is becoming clear that the issues of alien forest pests, let alone alien invasive species, is beyond forest resource and quarantine agencies to deal with. Other government agencies, including those involved with trade and commerce, environment, and transportation, are also implicated. New initiatives are underway in our countries to develop integrated approaches to addressing alien invasive organisms, and to avoid fragmentation of effort and direction.

26. The NAFC/IDSG has progressed in cooperatively addressing these science needs and to identify information gaps and opportunities for collaborative research between our three countries. The NAFC/IDSG's new subcommittees are to identify institutional capacity in biosystematics in North America, and to identify research needs and to coordinate research priorities for phytosanitary treatments, especially to address the problem of a lack of efficacy data needed to respond to issues related to the phytosanitary treatments for wood and wood products. The latter will focus on improving information on pathways for the introduction of alien forest pests, on ways to verify mitigation measures stated in shipping certificates, and on improved mitigation techniques, including better use and recovery of the fumigant, methyl bromide. Early detection new introductions of alien forest pests is the theme of this year's study group meeting. IDSG recognizes the broad representation of disciplines required to address non-native invasive weeds, but does not seek to add weeds to its Charter. A separate study group on weeds should be established.

27. The convergence between purely trade and biodiversity conservation issues points to a need for collaboration among national and international agencies dealing with these organisms and their impacts. The greatest need seems to be improvements in ways to share information about forest pests and terminology pertaining to quarantine pests and invasive species. The sparsity of records in the data bases may point to a need for improved incentives for scientists and related agencies to contribute information to the EFPISNA.

IMPLICATIONS THE COMMISSION MAY CONSIDER

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1  Terminology in this area is not uniformly applied. From a biodiversity and ecological perspective, the terms "alien species"and "non-indigenous species" are commonly used. Regulatory and related agencies tend to employ the terms "exotic" and "foreign" species.

2  Clinton, W.J. 1999. Executive Order 13112 of February 3, 1999. Invasive Species. Monday, February 8, 1999/Presidential Documents. Fed. Regist. 64(25):6183-6186. Definitions included in the Executive Order are: "Alien species" means, with respect to a particular ecosystem, any species, including its seeds, eggs, spores or other biological material capable of propagating that species, that is not native to that ecosystem. "Invasive species" means an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.

3  Niemelä, P., Mattison, W.J. 1996. Invasion of North American forests by European phytophagus insects: legacy of the European crucible. Bioscience 46(10):741-753.

4  Tohn J. Ewel, Dennis J.O. Dowd, Joy Bergelson, Curtis C. Daehler, Carla M. D. Antonio, Luis Diego Gómez, Doria R. Gordon, Richard J. Hobbs, Alan Holt, Keith R. Hopper, Colin E. Hughes, Marcy LaHart, Roger R.B. Leakey, William G. Lee, Lloyd L. Loope, David H. Lorence, Svata M. Louda, Ariel E. Lugo, Peter B. McEvoy, David M. Richardson, and Peter M. Vitousek. Deliberate introductions of species: research needs. BioScience. (August 1999) Vol. 49 No. 8:619.

5  Evans J. 1992. Plantation Forestry in the tropics. 2nd ed. Oxford:Clarendon Press. Quoted in Tohn J.Ewel et al. Op.Cit.

6  van Wilgen B.W., Cowling R.M., Burgers C.J., 1996. Valuation of ecosystem services. Bioscience 46:184-189 quoted in Tohn, J. Ewel et.al. Op.Cit.

7  US Congress, Office of Technology Assessment. 1993. Harmful non-indigenous species in the United States. US Government Printing Office, Washington D.C., OTA-F-565, pp.260-261.

8  Steve Strauss, Wout Boerjan, John Cairney, Malcolm Campbell, Jeffrey Dean, David Ellis, and Björn Sundberg. Forest biotechnology makes its position known: Commentary on GMOs. (In press, Nature Biotechnology, December 1999).

9  FAO. 1999. FAO Statement on Biotechnology. Rome, 2 December 1999. On line: http://www.fao.org/biotech/state.htm.

10  David Pimentel, Lori Lach, Rodolfo Zuniga, and Doug Morrison. Environmental and economic costs of non-indigenous species in the United States. BioScience (January 2000) Vol.50 No.1:53-65.

11 syn.Endothia parasitica (Murr.) P.J. & H.W. Anderson.

12  Humble, L.M.; Stewart, A.J. 1994. Gypsy moth. Natural Resources Canada, Can.For.Serv., Pacific Forestry Centre, Victoria B.C. Forest Pest Leaflet 75. Updated as an on-line document in 1999 (no authors given); see <http://www.pfc.cfs.nrcan.gc.ca/biodiversity/gmoth/index.html>. Humphreys, N.; Allen, E. 1998. The pine shoot beetle. Nat.Resour.Can., Can.For.Serv., Pacific Forestry Centre, Victoria B.C. Exotic Forest Pest Advisory 2.

13  Lesley A. Cree, Richard S. Hunt, Thomas H. Hofacker, Edward V. Podleckis. 1998. Pitch Canker (Fusarium subglutinans f.sp.pini) Pest Risk Assessment. Prepared for the Insect and Disease Study Group, North American Forest Commission, XXXII Meeting, Placerville, California, USA, September 1998: 38 pages.

14  Harrison, K.L.; Hurley, E.J. 1998. Butternut canker: a first record for New Brunswick. Can.For.Serv., Nat.Res.Can., Atlantic Forestry Centre, Fredericton, N.B. Tech.Note 315. Canadian Forest Service, Natural Resources Canada. Forest health in Canada: an overview 1998. Forest Health Network, Atlantic Forestry Centre, Fredericton, N.B., 60 pages.

15  China has countered this regulation with its own restrictions, effective January 2000, on coniferous wood packing material shipped from US and Japanese ports ostensibly owing to dangers of introducing the pinewood nematode, Bursaphelenchus xylophilus (Steiner & Buhrer). People’s Republic of China Joint Proclamation by the State Administration for Entry-Exit Inspection and Quarantine, Customs and the Ministry of Foreign Trade and Economic Cooperation, No. 23, November 1, 1999. Translated by Andrew Lam, Canadian Food Inspection Agency.

16  Humble, L.M.; Stewart, A.J. 1994. Op.cit.

17  Evans, H.; Mes-Hartree, M.; Kubicek, Q.B., 1993. Risk of transmission of pinewood nematode, its vectors and pine wilt to EC forests. Report of the EC/Canada/USA Technical Team. Unpublished report available from Natural Resources Canada., Canada Forest Service, Ottawa, ON. 25 pages.

18  In 1997, a working group of 12 countries spanning five continents, known as the Montreal Process Working Group, developed a framework of internationally agreed-upon criteria and indicators for the conservation and sustainable management of temperate and boreal forests; the framework developed by the Group contains an indicator that addresses alien forest pests.

19  The Global Invasive Species Program (GISP) is coordinated by the Scientific Committee on Problems of the Environment, in conjunction with the World Conservation Union, the United Nations Environment Programme (UNEP), and CAB International, with financial support from the Global Environmental Facility, UNEP, the International Council for Science (ICSU), and the National Aeronautics and Space Administration (NASA). For more on the GISP visit its Web site: <http://www.icsu.org/DIVERSITAS/Plan/gisp.html> .

20  CoP5/CBD will be held on 15-26 May 2000 in Nairobi, Kenya.

21  See URL: <http://www.fao.org/WAICENT/FaoInfo/Agricult/AGP/AGPP/PQ/En/IPPCe.htm>.

22  See URLS: <http://www.nappo.org> and http://www.nappo.org/97-8005_e.htm.

23  See URL: http://www.fao.org/WAICENT/FaoInfo/Agricult/AGP/AGPP/PQ/En/Info/info_e.htm .

24  The North American Forest Commission’s database Exotic Forest Pest Information System for North America [on-line]: <http://www.exoticforestpests.org>.

25  See URL: http://www.cec.org/english/profile/coop/Biodive_L.cfm?format=2

26  FAO. Report: Second Interim Commission on Phytosanitary Measures. Rome, Italy. October 4-8, 1999 [on line] http://www.fao.org/WAICENT/FaoInfo/Agricult/AGP/AGPP/PQ/En/IPPCe.htm

27  Report of the United Nations Conference on Environment and Development (Rio de Janeiro, 3-14 June 1992) Annex 1, Rio Declaration on Environment and Development. Distr.General. A/CONF.151/26(Vol.I), 12 August 1992. See URL: gopher://gopher.undp.org:70/00/unconfs/UNCED/English/riodecl

28  Commission of the European Communities. Communication from the Commission on the Precautionary Principle. Brussels, 2 February 2000, COM(2000)1. provides an attempt by the CEC to provide a basis for an internal and international debate on the precautionary principle.