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The Ecological and Socio-Economic Impacts of Invasive Alien Species on Island Ecosystems: Report of an Experts Consultation Contents

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The Ecological and Socio-Economic Impacts of

Invasive Alien Species on Island Ecosystems:
Report of an Experts Consultation


Executive Summary 3









Annex 1: Case Studies 18

Miconia Calvescens : A Major Threat for Tropical Island Rainforests 19

Introduced Mangroves in the Hawai’i’an Islands: Their History and Impact on Hawai’i’an Coastal Ecosystems 21

Achatina Fulica: the Giant African Snail1 23

Salvinia molesta in Sri Lanka 29





ANNEX VI: Press Release 46

ANNEX VII: Fouling of Marine Ecosystems by Invasive Alien Species: 47

ANNEX VIII: Research Needs: Invasive Alien Species on Islands 49

ANNEX IX: Draft Outline 51

Executive Summary
Invasive alien species (IAS) and their effects on the environment, economy, and human health have captured the attention of scientists, natural resource managers, and policy makers worldwide. Article 8(h) of the Convention on Biological Diversity (CBD) calls on member governments to “as far as is appropriate: Prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats, or species,” and calls for particular attention to be directed to geographically and evolutionarily isolated ecosystems, including islands. On behalf of the CBD and United States Agency for International Development (USAID), the Global Invasive Species Programme (GISP) convened a workshop in October 2002 to review the socio-economic and biological impacts of IAS on island systems. Experts from 10 countries, as well as GISP, the World Conservation Union (IUCN), and the World Conservation Monitoring Centre (WCMC) participated.
Participants in the Experts Consultation reached the following major conclusions: For biological and socio-economic reasons, islands are particularly vulnerable to bioinvasions. IAS can influence island environments at all levels of biological organization and also impact agriculture, fisheries, tourism, energy, water, and human health. Lack of access to extant technologies, particularly in small island developing States (SIDS) has resulted in IAS impacts that might have otherwise been avoided. While foreign aid can support IAS prevention and control efforts, it can also facilitate IAS introductions. Political pressure may exist to introduce IAS that will provide short-term economic benefits regardless of the longer-term biological costs. Although ballast water is a well-recognized pathway for marine bioinvasions, ship hull fouling by marine organisms is an often overlooked but significant pathway.
The following actions were recommended by the workshop participants: Develop informatics capacities to increase knowledge of and access to successful and cost-effective IAS prevention and management tools. Establish comprehensive IAS surveillance programs to enable early detection and rapid response. Undertake further assessments of IAS pathways and impacts, making the results widely available to resource managers and policy makers. Implement legal frameworks to minimize the risk of bioinvasion and develop alternatives to toxic anti-fouling agents.

The Ecological and Socio-Economic Impacts of

Invasive Alien Species on Island Ecosystems:

Report of an Experts Consultation

Invasive alien species (IAS) are non-native organisms that cause, or have the potential to cause, harm to the environment, economies, or human health. They are one of the most significant drivers of environmental change worldwide, consequently placing constraints on environmental conservation, economic growth, and sustainable development. IAS may also contribute to social instability and economic hardship. However, the costs to society greatly exceed those that can be measured in currency. They can also include unemployment, impacts on infrastructure, food and water shortages, environmental degradation, loss of biodiversity, increased rates and severity of natural disasters, illness, and lost lives.
The globalization of trade, travel, and transport is greatly increasing the diversity and number of IAS being moved around the world, as well as the rate at which they are moving. At the same time, changes in climate and land use are rendering some habitats more susceptible to biological invasions. In Article 8(h), the Convention on Biological Diversity (CBD) calls on member governments to “as far as possible and as appropriate: Prevent the introduction of, control or eradicate those alien species which threaten ecosystems, habitats or species.” However, national and international responses to the IAS problem have thus far been insufficient to counter their increasing toll on natural resources and society. One of the most significant barriers to policy development and implementation has been the paucity of reliable data on the biological and socio-economic impacts of IAS. Such information is desperately needed to convince decision makers of the scale of the problem and to enable stakeholders to determine the costs versus the benefits of their actions.
In March 2001, the Convention on Biological Diversity’s (CBD) Subsidiary Body on Science, Technology, and Technological Advice (SBSTTA) recommended (VI/5) to the sixth Conference of Parties (COP 6) that the CBD initiate assessments on the impacts of IAS. This recommendation was based on a desire to advance assessments on current priority issues, and to test a range of methods and modalities for assessments in accordance with paragraph (b) of decision V/20 (COP 5) and paragraphs 1 and 9 of recommendation VI/5 (SBSSTA 6).
As the International Thematic Focal Point for the CBD’s Clearing-house Mechanism (CHM), the Global Invasive Species Programme (GISP) was contracted to lead this project and to work with Parties and other bodies. The project brief provided by the CBD Secretariat is contained in document UNEP/CBD/SBSTTA/7/3.1
In order to inform development of and identify case studies for the assessment, an Expert Consultation on the Ecological and Socioeconomic Impacts of Invasive Alien Species on Island Ecosystems (hereafter “Experts Consultation”) was held under the auspices of the Global Invasive Species Programme (GISP) at the premises of the Hilton Hawaiian Village Beach Resort and Spa, Honolulu, Hawai’i, from October 18 to October 19, 2002. Seventeen individuals, with collective expertise in island systems around the world, participated in the consultation. The complete list of participants is contained in Annex II.



1.1 Professor Richard Mack, Co-chair of the GISP Evaluation and Assessment Working Group and Chair of the Experts consultation, called the meeting to order at 8:30 a.m. on 18 October 2002. He opened the meeting by thanking the coordinators and sponsors of the Experts Consultation, as well as the attendees for accepting the invitation to participate. Professor Mack said that the assessment of the biological and socio-economic impacts of IAS on islands (hereafter “Islands Assessment”) was the first of four ecosystem-based assessments that GISP will be undertaking on behalf of the CBD. Professor Mack then introduced Dr. Jamie K. Reaser, Executive Director of GISP, as meeting Facilitator and Dr. Laura Meyerson, Coordinator of GISP’s Evaluation and Assessment Working Group, as Rapporteur.
Dr. Reaser welcomed and thanked the participants and provided an overview of the Islands Assessment project, as well as the agenda for the Experts Consultation.


    1. Dr. Reaser explained that the CBD requested that GISP, as an International Thematic Focal Point for the CHM, assess the ecological and socio-economic impacts of IAS on island ecosystems. The request came as response to paragraph 6 (d) of SBSTTA recommendation VI/5 in which the decision was made, in accordance with paragraph 29 (b) of decision V/20 and paragraphs 1 and 9 of VI/5, to initiate assessments on the impacts of invasive alien species (IAS). The report arising from the assessment will also supports decision VI/23 of the Conference of Parties (COP) which urged research and assessments on the causes and consequences, as well as the prevention and management, of invasion alien species (IAS)2. The Expert Consultation is being convened in order to identify the expertise and information necessary for the Islands Assessment.

    2. According to Dr. Reaser, the primary outputs of the Islands Assessment will include a 15-page summary of the biological and socio-economic impacts of IAS on island ecosystems (Information Document) and a review article for publication in a refereed journal.


3.1. The Chair invited participants to provide brief case studies that illustrated both the ecological and socio-economic impacts of IAS on specific ecosystems and/or island ecosystems. Dr. Quentin Cronk (University of British Columbia) reported on several of the socio-economic and cultural drivers that have led to species introductions in several island ecosystems, the ecological impacts of the subsequent invasions, and outlined the five stages in the trajectory of a biological invasion. Dr. Lucius Eldredge (Pacific Science Association, Bishop Museum) reported on marine invasions in Hawai’i. Dr. John Mauremootoo (Mauritian Wildlife Foundation) reported on terrestrial invasions in Mauritius. Dr. Dennis O’Dowd (Centre for Analysis and Management of Biological Invasions) reported on the impacts of the yellow crazy ant (Anoplolepis gracilipes) invasion on Christmas Island. Mr. Sigurdur Thrainsson (Ministry for the Environment, Iceland) reported on biological invasions in Iceland. Dr. Moses Kairo (CAB International) reported on biological invasions in Caribbean Island ecosystems. Ms. Leliua Vaiutu (Department of Agriculture, Tuvalu) reported on IAS in Tuvalu.

    1. Each speaker was asked to address the following points during their presentation:

  • What are believed to be the major biological and socio-economic impacts of IAS on island ecosystems?

  • What variables (e.g., island history, ecotypes, island size and distance, pathways, climate, region of the world, etc) are believed influence the impacts of IAS on island ecosystems?

  • What are the “best practice” measures for the prevention, eradication, and control of IAS in island ecosystems? How do the principles/practices differ from continental systems?

Dr. Cronk addressed the historical and cultural links between mainland countries and islands that have contributed to many biological invasions:

  • The wet evergreen forest of Madeira Island, Portugal contains a high degree of endemism of great biological interest. Because it is a Portuguese island, Madeira has strong social and socio-economic connections to Portugal, and many plants, such as the sycamore maple (Acer pseudoplantanus), have been introduced from Europe into the Madeiran “laurisilva.”

  • Saint Helena, a United Kingdom dependent territory, was an important coaling station for steam ships when they went around the Cape of Good Hope between Britain and India. After the opening of the Suez Canal in 1869, St. Helena’s role as a coaling station diminished and the island was therefore in need of another industry. St. Helena began producing brown string for wrapping parcels. Native forest was cut down to plant introduced New Zealand flax (Phorium tenax). By the 1950s, demand for the flax string declined and the industry collapsed. The abandoned flax plants continued producing abundant seed which germinated on native tree ferns and spread rapidly, invading surrounding areas by up to five meters per year.

  • Mauritius, a British island off the coast of Africa, promoted species introductions in an attempt to increase land productivity. A high rate of biological invasion resulted. In contrast, Socotra Island in the Indian Ocean was never colonized by a European power. It remains relatively unaltered by humans, perhaps because of its dry climate, but more likely because it has not had the socio-economic factors driving the invasion.

  • Five different stages make up the invasion trajectory of an introduced species: (1) introduction, (2) naturalization, (3) facilitation, (4) invasive spread, and (5) stabilization and control. For woody plants, a typical invasion trajectory can take 100-200 years to proceed through all of the stages. At each stage of the invasion trajectory, different factors are important. Unfortunately, most invasions are not detected until stage 4, the exponential growth phase, rather than stages 1-3. As a result, there is little information on how to bring the population curves down and decrease growth and spread. Therefore, it is important to identify means to stop invasions in their introductory stages, to control established invasives, and to effectively address the socio-economic and cultural factors that are driving the invasions.

In summary:

  • Both cultural links and socio-economic factors are important drivers in biological invasions.

  • Invasions should be addressed according to where they fall along the invasion trajectory.

  • Characterization of cultural drivers and individual invasion trajectories will provide key insights how to address biological invasions.

Dr. Lucius Eldredge discussed marine invasions, particularly in Hawai’i.

  • Approximately 20% of Hawaiian biota is introduced. Of these, approximately 70% of the introduced species establish. Approximately 7% of the marine invertebrates are IAS. In Waikiki harbor, 7% of the species are IAS, but two species (i.e., Gracilaria salicornia and Hypnea musciformis) are causing the majority of the problems. The only introduced echinoderm in Hawai’i is the sea star (Asterias amurensis).

  • In marine ecosystems the following criteria usually indicate that an organism is an IAS: sudden appearance of the organism, the presence of an artificial substrate, and association with a dispersal mechanism and/or other IAS. Species of uncertain origin are termed cryptogenic species.

  • Surveys in Hawai’i indicate that the number of IAS present decrease sharply outside of the harbor.

  • The majority of the shipping routes in the Pacific go through Hawai’i, making Hawai’i a major recipient of IAS. Hull fouling is a greater problem in terms of IAS introductions than ballast water in Hawai’i, and likely in Pacific island insular systems as well. For example, approximately 80% of the introduced marine invertebrates in Hawai’i result from hull fouling.

  • Intensive biological inventories need to be undertaken in marine ecosystems along with anecdotal observations and reports. A global core team of taxonomists has been developed to assist in identification of unknown marine species. Voucher specimens should be deposited in the appropriate museums to aid in species identification.

  • An increase in introductions from hull fouling is expected as a result of the ban on TBT (tributylin), a toxic ship hull coating. Military and commercial ships have few problems with hull fouling because they are cleaned regularly.

  • Most industries that utilize marine IAS are not economically important, with the exception of (Kappaphycus spp.) which serves low-income communities. The major economically relevant near-shore industries are recreation and tourism. Currently the primary impacts due to IAS in Hawai’i are to biodiversity and aesthetics, although the mud blister worm (Polydora websteri), which can establish in cement tanks, put the oyster industry out of business.

Dr. John Mauremootoo reported on terrestrial invasions in Mauritius.

    • Four islands form Mauritius: Reunion, Mauritius and Rodrigues, and Round Island. The differences in the topography and the individual island’s history largely determine the extent to which they have been invaded.

    • Mauritius has a high degree of endemism. For example, 70% of flowering plants, 80% of birds, and 90% of reptiles are endemic.

    • Species extinctions occurred on Mauritius prior to the influence of habitat destruction. Shipwrecks introduced cats and rats to Mauritius even before the main island was settled. Thus, as much as 20% of the native species may have disappeared prior to human settlement.

  • Natural disturbances, cyclones in particular, have a major influence on the ecosystem. The native trees in Mauritius are very resilient to this disturbance, but the presence of IAS increases disturbance impacts, such as soil erosion.

  • Dramatic changes can occur in an ecosystem following biological invasions. For example, following human settlement and introduction, fire climax species may replace native species and completely changing soil erosion, nutrient cycling, and altering species dominance.

    • Rodrigues island was meant to become a productive “grain basket,” but this effort failed. Reforestation was attempted with introduced eucalypts (Eucalyptus, spp.), but has resulted in a water shortage.

    • Reunion is still forming via lava flows and 30% of its native forest remains, allowing recruitment of native species. On the island of Mauritius, recruitment of native species is low, and does not occur on at all on the island of Rodrigues.

  • Restoration of native canopy cover decreases light in the forest understory and helps to prevent IAS incursions. IAS control measures occur primarily in the conservation management areas. Active restoration efforts are occurring on Ile aux Aigrettes and Round Island. Future plans for control of IAS include moving to larger scale management programs (>100 hectares). This might include introductions of non-native tortoise species to replace the functional role of the now extinct Mauritian giant tortoise in the ecosystem. In the short-term, temporary introductions of other herbivores, such as goats, may be necessary to clear out vegetation.

  • There are no indigenous people of Mauritius, and colonization was relatively late, involving three different countries (i.e., Dutch, followed by the French who were responsible for most of the introductions, and then the British who continued introducing species). Therefore, a mentality of exploitation exists on the islands and there is little knowledge of native species. This in turn affects attitudes toward conservation and restoration, and also means that IAS are generally not considered to be a problem. However, the small human population on Mauritius also means that virtually every person can be reached and educated on the issues surrounding IAS, making the long-term prospects for addressing this issue very good.

    • The main industries of Mauritius (i.e., tourism, sugar, textiles, and off-shore banking), have thus far been little affected by IAS, but marine invasions pose a potential threat to the tourist industry.

Dr. Dennis O’Dowd reported on Christmas Island.

  • Island ecosystems vary in numerous ways that affect the extent and impact of IAS. These include the size of the island (e.g., island continent, island chain versus single island), the extent of biodiversity and endemism on the island, the topography, the age of the island, and the extent of human influence.

  • Christmas Island, south of Java, provides an example of many of the IAS problems facing other islands. Christmas Island has a high density of native red land crabs (Gecaroidea natalis), approximately 1 per square meter. These crabs live and burrow in the rain forest and migrate annually to the sea. The crabs are diurnal and omnivorous, but feed primarily on plant litter, and thus are the dominant consumers of rainforest detritus. An exclosure experiment revealed that excluding the crabs from the forest releases a large number of seedlings and detritus accumulates on the forest floor. Clearly, the crabs have a major influence on forest processes.

  • Yellow crazy ants (Anoploepsis gracilipes) were accidentally introduced to Christmas Island between 1915 and 1934, but have spread rapidly over the last decade. This IAS is a polygamous tramp ant with generalized nesting habits and a broad diet. It is continuously active, a “three dimensional forager.” Another species, the lac scale insect (Tachardina aurantiaca), interacts symbiotically with the yellow crazy ant. This is a cryptogenic species (i.e., of unknown origin). These two species have significant negative impacts on the ecosystem in general, and on the land crabs in particular, causing what has become known as an “invasional meltdown.” The ants kill the crabs by spraying them with formic acid. When the crabs are extirpated, there is a substantial increase in the accumulation of litter on the forest floor, a result that is similar to the exclosure experiments performed by the researchers. However, in this case it is playing out across the landscape, causing rapid ecosystem state changes. The scale insects produce sooty moulds over the leaves of forest trees, decreasing photosynthesis and thus tree survival. The ants collect honeydew and spit it out on the leaves, causing the scale population to explode and lowering the survival of the trees. The ants are also consumers of arthropods and vertebrates. Some data show that this is affecting the reproductive success of birds, which are important dispersers of fruits (e.g., the Christmas Island thrush, Turdus poliocephalus erythropleurus).

  • An island-wide survey on Christmas Island was designed to assess the impacts of the ant invasion. The results identified the spatial scale and intensity of the invasion, allowing delineation of the treatment areas and estimates on impacts and treatment costs. “Supercolonies” (an aggregation of two or more ant colonies which can consist of individuals from distinct nests) were 22.7% of the invasion and a total of nearly 2500 ha were infested. To address this invasion, an aerial campaign of poisoned fishmeal granular bait (0.01% Fipronil) was used and dispersed at a cost of AUS$ 247,000. Monitoring of efficacy, non-target effects, and evaluation of broader application are currently underway.

  • Some of the socio-economic factors on Christmas Island that are related to IAS include:

      • The presence of a detention center for political asylum seekers.

      • The presence of a space launch facility.

      • Issuance of new mining leases.

      • A nine-fold increase in shipping container traffic.

  • The invasion trajectory for the yellow crazy ant was long, perhaps because of water stress or the more recent biotic facilitation by the cryptogenic scale helped the ant to become successful. It is unlikely that the red crab was itself introduced. The high density of crabs probably results from a lack of predation following the extinction of endemic rats at the turn of the 20th century.

  • Eradication of the yellow crazy ant may be impossible since there are some areas in which the ants live in very low densities and because the non-target impacts of eradication might be unacceptable.

In summary:

  • In simple systems, IAS can unleash complex and unexpected outcomes. For example, a single IAS can produce a rapid state change and new associations can amplify the impacts of each species or novel associations with other IAS could form.

  • Immediate reporting of the impacts and assessments of IAS invasions are essential.

  • Surveys, use of geographic information systems (GIS), and monitoring of control efforts are critical.

  • The integration of science and policy is vital, and we need to ensure that all scientific studies are independent and transparent.

Mr. Sigurdur Thrainsson reported on invasive alien species in Iceland.

  • Geologically, Iceland is a very young country (~13 million years old), and because it is volcanic, it is still being formed. When settled in 847 AD, Iceland had 65% vegetative cover and 25% forest cover; today, only 25% of the vegetation and forest cover remains. This decrease in vegetative cover largely occurred during the first 300 years of settlement. In general, Iceland is low in biodiversity, but has many species on the red data list.

  • There are relatively few non-native species in Iceland, but IAS do present some of the most serious environmental problems. The worst IAS include the Nootka lupin (Lupinus lepidus), the American mink (Mustela vison), rainbow trout (Oncorhynchus mykiss), ruddy duck (Oxyura jamaicensis), Sitka alder (Alnus viridis), green spruce aphid (Elatobium abietinum), plus hundreds of flowering plant species.

  • The Nootka lupin, a nitrogen fixing plant species from Alaska, was intentionally introduced to Iceland to assist with land reclamation. Lupin exhibits different growth forms depending on latitude: in southern Iceland it grows tall and forms closed canopies, but in northern Iceland lower rainfall limits both height and density.

  • In Iceland, lupin is considered to have both positive and negative qualities, and is therefore removed from some areas while being planted in others. Lupin facilitates land reclamation because it does not require fertilization and therefore reduces short-term costs, and also has potential pharmaceutical uses for cancer treatment. However, it also changes successional trajectories, decreases light to native plants, and can be difficult to control and therefore has recently been removed from national parks. Further removal efforts are being considered despite the fact that it is still intentionally seeded on bare gravel flats.

  • Recent dialogues between the soil conservation service and the forest service have resulted in guidelines for lupin planting. The soil conservation service is also beginning to exploring the use of native species instead of lupin. However, because Iceland does not have another native species that is suitable to replace lupin for erosion control, its use may continue despite scientific evidence of its negative impacts on natural systems.

  • American mink was imported to Iceland in 1931 for use by the fur industry. It escaped a year later and the first breeding den was found in 1937. In approximately 40 years, mink fully colonized the coastal areas of Iceland with the exception of glacial rivers killing seabirds and affecting their nesting distributions. Mink have caused the extinction of the water rail (Rallus aquaticus) and the Slavonian grebe (Podiceps auritus). Mink escape from fur farms and attack eider duck colonies on other farms, and negatively affect fish release projects. Hunting is currently a control measure, but this is having little impact on mink populations.

  • The ruddy duck (Oxyura jamaicensis) was first imported to Britain from the U.S. and is now spreading to other countries, including Iceland. The first ruddy duck breeding attempts in Iceland were noted in 1990 and the first successful fledges occurred in 1994. Iceland eradicated ruddy ducks in 2002 because they destroyed the habitat of native bird species.

Experience in Iceland indicates that:

  • Island size, distance from neighboring countries, frequency and magnitude of species introductions, as well as climate, all influence biological invasions and their impacts. Islands differ from continental systems in their isolation, easier border control, and the invasion pathways.

  • More education and information on pathways is needed to prevent further introductions. In addition, prevention efforts must include border control, permits and/or fines for illegal species importation, as well as monitoring and research.

  • Eradication efforts must include early detection and action in order to be successful. Control should be implemented if eradication is not possible.

Mr. Moses Kairo reported on IAS in the Caribbean

  • The impacts of IAS on biodiversity and the ecology of the Caribbean are not widely recognized and little quantitative data on their effects exist. Instead, IAS are viewed mainly as a serious agricultural problem. However, IAS are increasingly becoming an environmental problem – in the last seven years at least six species have emerged as serious pests.

  • New factors, such as the need to meet international accepted standards for trade under World Trade Organization (i.e., those associated with the International Plant Protection Convention) have placed greater emphasis on the threat of IAS.

  • Disturbances such as habitat destruction or modification make small islands inherently more susceptible to IAS. The mesic climate favors establishment of IAS throughout the year. Primary biological impacts of IAS include displacement and competition between IAS and endemic species. Secondary biological impacts include soil erosion and flooding. However, some introduced species, such as those brought in for biological control, do produce beneficial impacts.

  • IAS have had significant political consequences in the Caribbean. For example, it has been suggested that in Grenada the government in power at the height of the hibiscus mealy bug (Maconellicoccus hirsutus) infestation acted too slowly and that this contributed to its defeat in the subsequent election.

  • There have been significant commercial income losses due to IAS impacts on agriculture and forestry as a result of trade embargoes. For example:

      • Grenada lost $18.3 million due to the Hibiscus mealy bug. Control costs exceeded one million dollars.

      • Trinidad and Tobago, Saint Vincent and the Grenadines reported millions of dollars (US) in losses related to IAS impacts on agriculture and forestry.

  • Several socio-economic factors influence the extent of IAS impact in the Caribbean. Many islands have close cultural links and there is rapid movement of people and goods at the local, regional, and global level. Thus, IAS can spread quickly throughout the Caribbean such as the hibiscus mealy bug which spreads at a rate of 2-3 islands per year.

  • Prevention (including quarantine exclusion) is the first line of defense against IAS, but has failed in multiple ways. On many islands there are inadequate resources for quarantine and the large number of potential entry points to the islands makes border security difficult. Relevant legislation may be out of date or non-existent. For example, in Curacao laws against importing harmful species are still under development, but in the meantime, agricultural produce and other organisms are brought in with little control. Because Curacao is a major travel hub, IAS established there are likely to spread.

  • Cooperation between governments may be lacking. For example, a country could be infected with mealy bug but not politically acknowledge its presence and therefore fail to take any measures to prevent spread to other countries.

In summary:

  • There is a lack of quantitative data on IAS in the Caribbean.

  • IAS pose a major threat to biodiversity.

  • The loss of income is the most significant socio-economic impact.

  • Quarantine is the most important defense.

  • Approaches to eradication and control do not differ from continental systems.

  • Government commitments for long-term efforts to manage IAS are not currently guaranteed since changes in administration can interrupt efforts.

Ms. Leilua Vaiutu reported on IAS in Tuvalu

  • Tuvalu is a small island nation in the Pacific made up of nine islands totaling 25 square kilometers. Forest covers approximately 67% of the land.

  • Three of the major IAS in Tuvalu are the coconut scale insect (Aspidiotus destructor) which damages food crops (e.g., breadfruit [Artocarpus altilis], sweet potatoes [Ipomoea batatas]), and impacts both social and economic systems; the termite (Neotermes rainbowi), which topples coconut palms, and the pink mealy bug (Macinellicocus hirsutus), a pest of the food staple breadfruit.

  • A biological control program exists for coconut scale. The Secretariat of the South Pacific (SPC) provides the control agents and they are released at the site of infestation. The agricultural department provides advice on how to treat pests and planting of resistant trees. The South Pacific Regional Environmental Programme (SPREP) also works closely with environment and the local government.

Tuvalu’s needs include:

  • Identification of non-native and native species.

  • IAS survey results from other countries.

  • Expert technical advice and facilities for IAS identification.


Following the presentations, the facilitator led the participants through a discussion based on the questions listed below. In addition to the summaries provided below, a list of the main points and issues arising from the presentations and follow up facilitated discussions is contained in Annex V:

  • What case studies (data) exist to document the impacts of IAS on island ecosystems and through whom can this information be obtained?

  • What gaps in knowledge exist and how might these gaps be filled? [gaps in knowledge, opportunities for filling gaps]

  • What can be accomplished in an assessment of the impact of IAS on island ecosystems in 9-months? [goals]

  • What are the steps to undertaking a 9-month assessment (including timeline)? [timeline]

  • Who needs to be involved in the assessment and how? [contributors – roles and responsibilities]

  • What are the first steps and who will take them?

  1. What case studies (data) exist to document the impacts of IAS on island ecosystems and through who can this information be obtained?

The following brief summary case studies with cited references can be found in Annex I of this document. These include contributions from participants and other stakeholders.

  • Miconia calvescens: a major threat for tropical island rainforests.

  • Introduced mangroves in the Hawaiian Islands.

  • Invasive species and coral reefs.

  • Achatina fulica, the giant African snail and Pomacea canaliculata, the golden apple snail

  • Salvinia molesta in Sri Lanka.

Additional resources suggested by meeting participants included eight papers on coral reef non-indigenous and invasive species resulting from a symposium of the same name held at the Bali International Coral Reef Symposium held August 27, 2000. These are now available on the web at:

The following paper was suggested:

Howarth, F. G., G. Nishida, and A. Asquith. 1995. Insects of Hawai’i. In E.T. LaRoe, ed., A report to the nation on the distribution, abundance and health of U.S. plants, animals, and ecosystems. U.S. Department of Interior, National Biological Survey,

Information on biological control of Cactoblastis in the Caribbean can be obtained from Bob Pemberton, USDA ARS biocontrol ( Additional information and case studies can be found among the papers listed in the attached bibliography, Annex IV.

    1. What gaps in knowledge exist and how might these gaps be filled?

The following summary arises from the facilitated discussion. It does not represent an exhaustive list of the gaps in knowledge and potential responses, but a list of gaps in information that meeting participants believe to be a priority for research and other actions.

Issue: Prevention, early detection, and rapid response are widely accepted as the best ways to safeguard islands from IAS impacts. However, a lack of public education on IAS issues, poor cooperation between countries, a substantial lack of trained personnel to identify and intercept IAS at country borders, and few, if any, mechanisms to respond to nascent outbreaks of IAS present significant obstacles. Furthermore, lack of ecological and taxonomic information limits the ability to predict the impacts of IAS or even simple identification of species as introduced or native to an area.
Response: Build capacity to prevent and respond to IAS introductions in the following ways:

  • Raise awareness of the biological and socio-economic impacts of IAS by educating governments, local communities, relevant industries, and tourists. These sectors are often the first line of defense in preventing or predicting a biological invasion.

  • Apply methodology from social science research in order to identify community values and ways of involving communities in the IAS issue.

  • Engage trade related bodies (e.g., World Trade Organization) in island IAS issues.

  • Deposit voucher specimens in appropriate museums to assist with species identification.

Issue: Ballast water is recognized as a global pathway for IAS transport. However, the fouling of marine organisms on ships and other mobile structures is another significant invasion pathway that requires greater attention.
Response: Hull fouling must be considered a high priority by policy makers, natural resource managers, relevant industries, and investigators. The following steps should be undertaken:

  • Support and undertake studies of fouling as an invasion pathway, as well as evaluating the biological and socioeconomic impacts of fouling organisms on marine ecosystems.

  • Develop and enact best management practices and policies to physically clean ships hulls and marine equipment so as to minimize the risk of transport of fouling organisms.

  • Develop environmentally sound alternatives to the toxic anti-fouling agents that are gradually being removed from use.

  • Develop surveillance programs for detection and penalties for “polluters” who introduce IAS via fouling.

Issue: Relatively little quantitative data are available on the impacts of IAS on island ecosystems. At present there are no adequate tools to predict which introductions will produce successful invaders, or even quantitative and qualitative data on which introductions fail and why. This uncertainty poses considerable difficulty for policy-makers.
Response: Greater quantification will lead to better decision prevention policy. The following steps need to be taken:

  • Conduct research on how to incorporate stochastic processes important in the early stages of invasion into population models. Better population models may lead to more successful predictions of which species introductions will become IAS.

  • Improve knowledge of invasion risk and patterns of spread in order to prioritize species risk and reduce uncertainty by collecting higher quality data and improving modeling. In particular, identify the minimum thresholds for the initial population size of an introduction in order for an invasion to succeed.

  • To predict and prevent future invasions, pathways for the introduction of species to island ecosystems must be identified. This is one of the most important measures that can be taken; therefore, more information is needed to develop tools to identify pathways.

Issue: A general assessment of the impacts of IAS on islands is difficult since there is little quantitative data is widely available. Experiments can be difficult to conduct on hard to access islands. Consequently, experimental data is often lacking and contributes to conservation failure in managing IAS on islands.
Response: Islands have limited resources, making the protection of ecosystem services particularly important. Because the science of identifying and quantifying ecosystem services is in its infancy, better methods are needed. Therefore, the following research should be facilitated:

  • Quantify ecosystem services on islands to improve prediction of invasions, to prioritize actions, and to better understand IAS impacts.

  • Conduct more ecological experiments, in the form of perturbations, field trials or adaptive management.

  • Conduct research to enhance understanding of how exogenous factors (e.g., climate change, physical disturbance) exacerbate the impacts of IAS.

  • Determine whether a lag phase exists for the realization of IAS impacts (i.e., while it is understood that some IAS undergo a lag phase prior to becoming invasive, is there also a lag before impacts of an invasion become apparent?)

  • Conduct more research to understand how biological invasions on islands differ from continental invasions.

  • Conduct complete biological inventories on island ecosystems, particularly on small islands. Despite islands having small and tractable biotas, most bioinventories are far from complete, particularly for invertebrates. On islands, more than on any other system, complete bioinventories are achievable.

  • Consider bioinventories from IAS source regions (for little known invertebrate groups in particular) to aid understanding of pathways of invasion.

Issue: The introduction of IAS into new ecosystems can lead to the formation of novel biological associations. Several examples exist such as association of West Nile virus and Asian tiger mosquitoes (Aedes albopictus) in the United States. In most cases, these novel associations have not been predicted and little is known about the impacts of the species-species and species-environment interactions.
Response: Include the formation of novel biological associations in risk evaluations for species introductions. While these associations are by definition new and therefore unpredictable, indicators and predictive capacity should be sought.

  1. What can be accomplished in an assessment of the impacts of IAS on island ecosystems in nine months? What do we want to encapsulate as the main message to get across?

Participants agreed that the biological and socioeconomic impacts of IAS on island ecosystems are increasingly large and significant problems that warrant serious attention. They believed that nine months provided a relatively short period of time to address these issues. Therefore, they recommended that attention be focused on the most pressing issues and on those areas where progress can be made to stop or mitigate invasions and their impacts. They believed that the following points must be conveyed through the assessment: IAS impacts cut across ecological, social and economic sectors and the impacts can be rapid, acute, chronic, and cryptic with long-term cascading effects. However, invasions are potentially manageable and their effects may be reversible in some cases. Prevention is the first line of defense. This can best be addressed through capacity building, sharing resources, and through networking and partnerships. For example, sharing biological control agents across countries or regions may produce significant cost savings.

      1. Who needs to be involved in this process and how?

IAS affect all sectors of society. Participants recommended that case studies be used to reflect the linkages to stakeholders in industry, government, the health sector, agriculture, environmental sector, non-profits and local communities, as well as the news media.

      1. What are the first steps and who will take them?

Participants recommended that the following steps be undertaking immediately following the meeting: 1) compile the summary information and 2) collect relevant case studies. Deadlines and a process were established for contributions and reviews of the documents.


Participants identified a series of actions that they wished to take as a group before the close of the meeting. They then divided into four working groups and produced the following documents. These products are included in this report in Annexes VI through IX.

  • Press Release Prepared at the Islands Assessment Workshop October 19, 2002: Action Against Aliens on Islands Planned
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