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Les espèces envahissantes dans l’archipel néo-calédonien

Marie-Laure Beauvais
Alain Coléno
Hervé Jourdan

Part one. Synthesis and recommendations

Biosecurity systems

Texte intégral

1While the concept of environmental protection conflicts with the notion of progress as that term was understood in the twentieth century, the impact of invasive species seems increasingly intolerable, especially in island situations. The world’s perception of risk management is changing. With the globalisation of trade, international and national biosecurity systems are proving inadequate to halt the spread of harmful organisms and are attracting criticism. In particular, some authors consider systems that focus solely on the risks associated with the introduction of alien species too limited, and think that effective systems should take into account the motives for such introductions and seek ways of responding to them.

2Until recently, only agricultural risks were taken into account; little attention was paid to damage to biodiversity and natural environments. In this regard the precautionary principle should carry increasing weight in future, as indeed is recommended in the CBD (Convention on Biological Diversity). At the time of writing, the WTO (World Trade Organisation) has to comply with the sanitary and phytosanitary measures (SPM) defined in the International Plant Protection Convention (IPPC). International meetings were held recently to foster cooperation between the CBD and IPPC authorities. Of course, addressing the question of invasive species follows the same logic as addressing crop health hazards: both involve combating the introduction and establishment of alien organisms.


3To date, there is no scientific principle or reliable procedure for predicting the invasive potential of a species in a new geographical area. But for every organism, existing behavioural data from other regions could be put together. In particular, the fact that a plant has infested an environment similar to New Caledonia’s, in another country, might suggest that it has the potential to become established and invasive in New Caledonia. This is equally true of arthropods and pathogens, if the plants they depend on grow in New Caledonia. This point at least highlights the extent of the bibliographical work to be done in the event of an alert, or in case of doubt. Nonetheless, use of effective instruments for assessing the scale of the potential risk is essential.

Figure 1. Analysis of phytosanitary risk – stage 2

4Evaluation of phytosanitary risk and determination of the appropriate level of protection are governed by the IPPC’s Pest Risk Analysis (PRA). This analysis must adhere to the International Standards for Phytosanitary Measures (ISPMs) and must be performed in three stages:

  • Stage 1 is to identify a pest and /or pathways that may allow the introduction or spread of a quarantine pest;
  • Stage 2 is to assess the pest risk (likelihood of entry to the territory, establishment and spread, economic importance) using the flow chart in Figure 1 above;
  • Stage 3 is to manage the pest risk identified in Stage 2.

5The goal is to provide biological or other scientific or economic arguments for deciding whether or not to regulate an organism. It also means defining the type of phytosanitary measures to be taken. A country’s environmental and phytosanitary protection laws have to comply with international obligations. There are several possible approaches. One is to adopt a blacklist on the basis of “innocent until proven guilty”. The IPPC and most countries draw up (and update) lists of pests that it is formally prohibited to import, even with quarantine. Any species not listed can be imported, provided it is not host to a prohibited species. This does not prevent a country from conducting a risk analysis of any species seen as possibly noxious. Some scientists such as the American ecologist Daniel Simberloff hotly contest the “presumption of innocence” approach. Simberloff, for example, objects to the primacy of free trade over environmental concerns in the United States. Countries that have been hard hit by infestations of non-native species, such as Australia and New Zealand, take a different approach: the white list or “guilty until proven innocent” approach. Any species not on the list must be subjected to a phytosanitary analysis. This is the approach recommended in the new European strategy on invasive alien species.

6Assessing weed risk involves mainly the first two stages of the pest risk assessment process, i.e. the process for determining whether a pest has, or has not, the characteristics of a quarantine pest or those of a regulated nonquarantine pest. The Weed Risk Assessment system (WRA) was originally developed in Australia. It is designed to be efficient, transparent and to save time and money. It takes the form of a questionnaire and a score sheet; it has 49 questions about the plant’s history and biogeography, climate, range, biology, ecology, plant type etc. The plant is accepted or rejected on the basis of the final score. One limitation of the WRA is that it produces a certain number of false positives. It may also reject species that are useful although invasive. The model is now being adapted and should be a relevant instrument for New Caledonia. Directives on weed risk assessment in developing countries can be obtained from the food and Agriculture Organisation (FAO).

7Weed risk assessment always involves a search of the literature, gathering and interpreting all available information about a potential weed. The first information required, in compliance with IPPC standards, is the list of alien plant species in the country. Some paper and electronic sources are vital: regional flora, information on the biology, ecology and distribution of weeds, etc. Networking among experts is another important part of the process. The IPPC provides an international framework for preventing the introduction and spread of pests of plants and plant products. Revised in 1997 and added to since then, it is accepted as authoritative by the WTO.


8Responses to pest problems vary considerably from country to country. New Zealand is internationally recognised as having the world’s most highly developed biosecurity system. Its quarantine system is particularly efficient. It is mainly based on the Biosecurity Act of 1993, which aims to prevent the spread of accidentally introduced invasive organisms and keep any new ones out of the country. The responsibility for implementing quarantine falls to the Ministry of Agriculture and Forestry (MAF). The Hazardous Substances and New Organisms Act of 1996 governs the operations and obligations of people and organisations introducing such organisms intentionally. Authorisation must be obtained from ERMA, the Environmental Risk Management Authority. One result of this law has been an effective halt to imports of new alien organisms for leisure purposes.

9Import controls on “hazardous goods” reduce the number of inadvertent introductions. All plants and plant products are prohibited entry into New Zealand unless an Import Health Standard has been issued. There are 500 of these for animals, plants and related organic material and products. The MAF’s quarantine system is extremely well equipped and inspection is carried out at all ports of entry to the country, using dogs, X-ray equipment etc. There are spot fines of NZ$ 200 for breach of the law. The same applies to international mail. As regards shipping, new import health standards for shipping containers were recently introduced. Inspections are carried out at ports of entry to the country. According to some authors New Zealand may spend 1% of GDP on biosecurity (see paper by A. Sheppard et al.).

10Hawaii is a rather different case. As a member of the United States it suffers from the federal authorities’ decision to focus primarily on protecting predominant agricultural activities and paying little attention, so far, to ecosystem protection. But Hawaii is extremely vulnerable to invasions. It is the Hawaii Department of Agriculture, Plant Quarantine Branch (HDOA-PQ) that is responsible for regulating and controlling the import and transport of all non-native plants and animals. During the 1990s, following a controversy about the extension to Kahului airport and its potential impact on Haleakala national park, the HDOA conducted a pest risk assessment on the airport. That study was used to improve the airport’s quarantine programme, and also led to proposals for improvements for the entire country (see paper by A. Sheppard et al.).

11Australia’s biosecurity system is far more similar to New Zealand’s. Australia has suffered so many invasions that 16% of its flora are exotics, 15% of its mammals are invasive aliens and about 20% of its insects are non-native. All in all, alien plants cost AU$ 4.4 billion a year, not counting the environmental damage. The approach adopted is based on a white list of authorised species. Each new species is subjected to an import risk assessment and an environmental risk assessment before being admitted to the country. This procedure, paid for by the importer, must follow a tightly regulated and quite long protocol during which the public are also invited to put their views, which ensures close public involvement in the pest problem (for further information see paper by A. Sheppard et al.). Australia’s equivalent of New Zealand’s Import Health Standard is its Import Risk Assessment (IRA).

12French Polynesia is another case worth examining. Since February 2004 this French overseas territory has had a fairly independent status as a “pays”, with its own government. Its Ministry of Agriculture and Livestock and its Rural Development Department are responsible for plant and animal quarantine on entry, but also for trade between islands. Measures to combat the introduction of invasive species are based on two statutes: the 1995 resolution on the protection of nature and the resolution on plant protection. The former prohibits the introduction or import of any plant or animal species that does not exist within the territory. Applicants for exemption must pro-vide proof of the innocuousness of the species concerned? a highly dissuasive requirement. The resolution on plant protection lays down a list of pests whose import is prohibited. An inter-ministerial Committee was set up in 1998 to combat miconia and other weeds endangering biodiversity. It may in time be extended to cover all invasive pests and weeds (for further information see paper by A. Sheppard et al.).

13In any case there is no doubt that successful preventive measures against an invasive species that has not yet been introduced is directly correlated with the efficiency of the biosecurity system. Thus New Zealand has never yet been invaded by the red imported fire ant, although RIFA has established in Australia (2001), Taiwan (2004), Hong Kong (2005) and continental China (2005). The New Zealand authorities also say they have eradicated the gipsy moth (Lymantria dispar), unseen since May 2005. The Ministry for Agriculture and Fisheries had been operating a surveillance programme since 1993. When a gipsy moth was caught in South Auckland in 2003 an eradication programme was launched immediately, costing NZ$ 5.4 million for two years of treatment.


14One factor that facilitates surveillance in New Caledonia is that there are only two main ports of entry to the territory. About 99.9% of goods pass through the port of Nouméa, which is also where nearly all cruise ships stop over. The international airport at Tontouta is the only point of entry for air traffic, making it the main point of entry for invasive species that cannot survive long in transport. Residents are far more likely to introduce alien species (exotic plants especially) than are tourists. However, there are also new entry points with customs inspections, such as those connected with mining at Koumac and Goro, and tourist ports of call (Touho, Lifou, Hienghene). All postal parcels go through Nouméa. Parcels containing plant material ordered from companies abroad have to be accompanied by a customs declaration, and can therefore be inspected. The risk from private mail is much greater.

15The legal quarantine provisions for pests of plants is broadly based on European equivalents, with some particular features appropriate to isolated regions (see Appendix 2 of paper by M. Delos et al.). It is based on two resolutions by New Caledonia’s Congress: one passed on 11 August 1992, for the general framework of plant protection measures including plant quarantine, and one passed on 18 October 1996 which concerns plant quarantine more specifically. The quarantine lists are “negative” for undesirable organisms and their potential carriers, and “positive” for goods known to potentially carry undesirable organisms. Because of New Caledonia’s particular characteristics as a group of islands that have historically been isolated by distance from flows of people and plants, the quarantine system is backed up by two other types of measure. The first type is taken by the executive powers in cases of imminent danger (introduction or propagation of an organism not on the negative list). The other is the introduction of an import permit for plants or plant products not otherwise covered by the regulations. This gives the administration the means to exercise continuous control over declared imports.

16There are three negative lists of pests and undesirable plant material and growing mediums. They feature as appendices I, II and III to the New Caledonia government’s resolutions (see paper by M. Delos et al.). In addition, there is a fourth appendix that lays down the import conditions for authorised goods and plants. An import permit is almost always required (Appendix IV) except for large volumes of plant produce, fruit and vegetables imported from particular regions (Australia, Chile, European Union, New Zealand, United States). Any product or produce from a dubious origin and which might harbour for example such pests as Bractocera or Anastrepha, which are established in some parts of America, must be treated. However, there is one significant gap in the regulations: wood for transport-related purposes (wedges, packaging for non-agricultural goods) is not covered. Only rough timber and manufactured wood products are covered, with measures appropriate to the risk.

17Overall, New Caledonia’s legislative arrangements seem satisfactory for preventing the introduction of invasive pests of plants. Some improvements could be made, however. Apart from the wooden packaging problem, they concern the animal list in Appendix I, which is too short (particularly for vertebrates, arthropods and molluscs). It would also be desirable to pay special attention to second-hand vehicles and machinery, e.g. farm machinery and combine harvesters, that have been used for farm work or forestry outside New Caledonia. And there is so far no control of invasive animal species that are not plant pests and do not carry diseases monitored by the veterinary services. Finally, there are some obvious absences from the quarantine lists, such as the rust fungus Puccinia psidii, which attacks many Myrtaceae species? and Myrtaceae should be on the plants list as potential rust vectors.

18As regards the administrative quarantine system, a decree on the organisation of the New Caledonia regional customs department (24 April 2002) and a New Caledonia government decree of 22 February 2002 define the attributes of the food, veterinary and rural affairs department, DAVAR (Direction des Affaires Vétérinaire, Alimentaire et Rurale) (see Appendix 2 of this report and paper by M. Delos et al.). The veterinary, food and phytosanitary inspection department is responsible for plant and animal quarantine, inspection, surveillance and pest control within the territory. This is a fairly conventional arrangement: a double system of inspection with an initial sorting of goods at the customs stage using a customs code, the goods being subjected to a phytosanitary check by the DAVAR if necessary. The division of roles between the different monitoring and inspection actors is the same in many countries (see paper by M. Delos et al.).

19As regards resources, no doubt the weakest point of the New Caledonian system, it would be useful to have at least one itinerant officer plus two officer at border points, to monitor the new ports of entry in Northern Province. Further, with more inspectors, larger volumes of goods could be inspected. X-ray checks on shipping containers and postal parcels are altogether insufficient. But above all, a phytosanitary identification laboratory and a quarantine station are needed. These are indispensable, for example for assessing the environmental impact of hazardous plants whose introduction is nonetheless desirable.


20Major surveillance and control activities are defined by the Congress resolution of 11 August 1992 (see above). Five kinds of action are involved: monitoring of plant and crop production, pest identification, farmer alerts, inspection of plant production and multiplication sites, and surveillance of the introduction, multiplication and use of biological control agents (such organisms can prove to be formidable pests). The administrative arrangements for surveillance and control are defined in the decree of 22 February 2001. Surveillance is an essential component of the biosecurity system (see Table 12 below and Appendix 4 of the paper by M. Delos et al.). There are two aspects: general surveillance and spot checks. The latter would include, for example, the prospecting work carried out in attempting to eradicate bunchy top. General surveillance can usefully harness observations by farmers, researchers, associations and learned societies.

Table 12 – Territorial surveillance and post-introduction risk control and management: who does what

Table 12 – Territorial surveillance and post-introduction risk control and management: who does what
  • * DDR: Direction du développement rural.
    DRN: Direction des ressources naturelles.
    DDE-E: Direction du (...)

Note **

21There is a lack of staff and resources for monitoring and inspection, particularly inspection of plant production and multiplication establishments. The division of work between the provincial services does not seem clearcut. Farmer alerts, which the regulations also provide for, remain somewhat theoretical even though they would be an effective tool for managing pests that have established, and also for institutional communication. Surveillance of non-agricultural areas and forests is still embryonic. A far more rigorous surveillance network than at present will have to be set up, especially in Southern Province. This region has the most ports of entry as well as most of the economically active population. It is wide open to accidental introductions owing to the flow of goods through it, and also to intentional introductions (introduction of potentially invasive ornamental plants is more likely in more densely populated areas). Most of New Caledonia’s nursery gardens are in this province, too, and 90% of them are not inspected. These weaknesses in the surveillance and control system doubtless contributed to the failure to eradicate bunchy top (see also p. 229). An effective surveillance and prospecting system requires networking between provincial services. Such a network has yet to be set up. The absence of organised private enterprise in the plant pest control prescription sector, such as exist for animals in the veterinary business, is a major handicap. New Caledonia’s research centres, farmers and environmental protection associations could act as relays in the field for a certain number of species and ecosystems.

Notes de fin

* DDR: Direction du développement rural.
DRN: Direction des ressources naturelles.
DDE-E: Direction du développement économique et de l’environnement.
DAE: Direction des affaires économiques.

Table des illustrations

Légende Figure 1. Analysis of phytosanitary risk – stage 2
Fichier image/jpeg, 282k
Titre Table 12 – Territorial surveillance and post-introduction risk control and management: who does what
Légende Note **
Fichier image/jpeg, 221k

© IRD Éditions, 2006

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