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Invasive species are leading driver of biodiversity loss in the Pacific. They impact ecosystem resilience, ecosystem services and the future ability to adapt to climate change.

A weed is any plant that is in the wrong place and requires action to reduce its effect on the economy, environment, human health or amenity. Weeds are also known as invasive plants.

Rodents are a key pest to agricultural and rural island communities of the South Pacific, but there is limited information of their impact on the crops and livelihoods of small-scale farmers.

The influence on crop damage of Rattus norvegicus, Rattus rattus, and the native Polynesian rat, Rattus exulans, was studied during the establishment of a rat control program for the Tongan Department of Agriculture in 1969. This was the first long-term study of Tongan rodents. Previous scientific literature on Tongan mammals is very sparse. The Kingdom of Tonga, or Friendly Islands, consists of approximately 150 small islands with a combined area of about 256 square miles at lat 21 0 S. The majority of these islands are composed of raised coral limestone ; however, there is a row of six volcanic islands on Tonga's western border. Tongatapu, the location of the government center, is the largest and most important island. The Ha'apai island group lies 80 miles north of Tongatapu, and 150 miles north is the Vava'u group. Fiji is 420 nautical miles east and Samoa is 480 miles north. The climate is tropical and is influenced seasonally by trade winds. Since Captain Cook's first visit in 1773, Western civilization has brought trade, missionaries, and perhaps rats to Tonga. With this shipping came numerous introduced plants and animals. The arrival dates for the common rat, Rattus norvegicus, and the "European" roof rat, Rattus rattus, are not known, but are believed to be more recent, probably since the increase of regular shipping trade and the construction of wharves. Presently rodents account for approximately 20 percent of the agricultural losses and $50,000 worth of economic loss each year (Twibell, unpublished). This is a conservative estimate based on damage counts and observation. In some areas rats destroy or damage up to 50 percent of the coconuts, which represent the main economic crop in Tonga. THE INFLUENCE on crop damage of Rattus norvegicus, Rattus rattus, and the native Polynesian rat, Rattus exulans, was studied during the establishment of a rat control program for the Tongan Department of Agriculture in 1969. This was the first long-term study of Tongan rodents. Previous scientific literature on Tongan mammals is very sparse. The Kingdom of Tonga, or Friendly Islands, consists of approximately 150 small islands with a combined area of about 256 square miles at lat 21 0 S. The majority of these islands are composed of raised coral limestone ; however, there is a row of six volcanic islands on Tonga's western border. Tongatapu, the location of the government center, is the largest and most important island. The Ha'apai island group lies 80 miles north of Tongatapu, and 150 miles north is the Vava'u group. Fiji is 420 nautical miles east and Samoa is 480 miles north. The climate is tropical and is influenced seasonally by trade winds. Since Captain Cook's first visit in 1773, Western civilization has brought trade, missionaries, and perhaps rats to Tonga. With this shipping came numerous introduced plants and animals. The arrival dates for the common rat, Rattus norvegicus, and the "European" roof rat, Rattus rattus, are not known, but are believed to be more recent, probably since the increase of regular shipping trade and the construction of wharves. Presently rodents account for approximately 20 percent of the agricultural losses and $50,000 worth of economic loss each year (Twibell, unpublished). This is a conservative estimate based on damage counts and observation. In some areas rats destroy or damage up to 50 percent of the coconuts, which represent the main economic crop in Tonga.

Global biodiversity loss is disproportionately rapid on islands, where invasive species are a major driver of extinctions. To inform conservation planning aimed at preventing extinctions, we identify the distribution and biogeographic patterns of highly threatened terrestrial vertebrates (classified by the International Union for Conservation of Nature) and invasive vertebrates on ~465,000 islands worldwide by conducting a comprehensive literature review and interviews with more than 500 experts. We found that 1189 highly threatened vertebrate species (319 amphibians, 282 reptiles, 296 birds, and 292 mammals) breed on 1288 islands. These taxa represent only 5% of Earth's terrestrial vertebrates and 41% of all highly threatened terrestrial vertebrates, which occur in

Understanding vector routes for invasive species (i.e. the routes by which pest plants and animals move from place to place via human assistance) is a key element in global and national efforts to reduce risks and limit the further spread of invasive species. This report is divided into two main sections. The first section provides a quantitative analysis of air and sea movements between the countries and territories of the Pacific. The second section summarises information on eighty existing or potential invasive plants and animals to Pacific islands. While the GEF project with which this report is linked is limited to SPREP countries, the analysis also includes the territories of the region (with the exception of Pitcairn Island). This is essential since some territories are pivotal to understanding vector routes and transport ‘hubs’ in the region. For the same reason, flights from Pacific islands to Hawaii are included, as well as including Hawaii in the analysis of the selected invasive species. There is significant variability in the volume and patterns of ship movements and aircraft flights between the countries and territories of the Pacific, which is consistent with their diverse sizes, economies, exports, and political linkages. A few countries emerged as significant ‘hubs’ for sea and air transport within the region. (Refer to Tables 1 and 2 for summaries.) In the northern Pacific, Guam emerges as the “high risk” country, given its high levels of total merchant ship and oceanic fishing vessels as well as the largest number of weekly flights to other Pacific island countries (139) and to Asian destinations (148). In the central southern Pacific, Fiji is the major transport centre with a large volume of merchant shipping, cruise liners and itinerant yachts (585 yearly visits) and relatively high numbers of weekly flights both within and outside the region. To the east, French Polynesia has a smaller annual number of merchant ship visits, but when other shipping activity is included, as well as 26 weekly flights to the USA (including Hawaii) and more within the region, it emerges as an important vector route. (It already has a significant number of invasive species). Papua New Guinea and New Caledonia are important countries in the western Pacific for shipping volumes; New Caledonia also for visits by yachts (500/yr). Papua New Guinea has extensive air links with Australia, another source of tropical invasives, but very few within the Pacific. New Caledonia has a larger number of weekly flights than Papua New Guinea spread within the region, as well as to Asian, Australian and New Zealand destinations. The information in the second section on eighty invasive species provides evidence for the links between trade, travel and the distribution of invasives. Vector routes and methods of spread are identified. It also highlights the importance of early detection and eradication if Pacific countries are to be more effective at limiting the arrival and spread of invasive species.

Study on gathering Ciguatera Fish Poisoning records and questionnare responses from Pacific Island Countries and Territories highlights the extent of ciguatera in the Pacific, the need for research and many unanswered questions about ciguatera and its place in the health of coral reef ecosystems. Ciguatera is seen as a biomarker of coral reef degradation and the importance of monitoring research is worth whilst to fill gaps of knowledge as to the environmental causes of outbreaks and a method by which envrionmental managers may control those parameters affecting outbreaks.

Invasive species are plants or animals living where they don’t belong and causing harm. Also known as introduced, alien or pest species, they are species that have been brought into a new environment and whose introduction can : Threaten many native and endemic species with extinction by eating them or competing for food, light, water or shelter Damage ecosystems so that they are less able to provide essential services such as clean water, erosion protection, insect control etc Harm humans and animals from bites, stings or disease Reduce the tourism attractiveness of an area Impact on the species that Pacific Islanders rely on for their livelihoods