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A report prepared by the Invasive Partnership for the Pacific Islands Forum Leaders Meeting, Palau July 2014 as requested by the Micronesian Chief Executives in Resolution 19-01

Since the 1950's, 19 algal species were intentionally (e.g., aquaculture food) and/or accidentally (e.g., ballast water) introduced into Hawaii (Glenn and Doty 1990).

This paper develops a model of invasive species control when the species’ population size is unknown. In the face of an uncertain population size, a resource manager’s species-control efforts provide two potential bene ts: (1) a direct bene t of possibly reducing the population of invasive species, and (2) an indirect bene t of information acquisition (due to learning about the population size, which reduces uncertainty). We provide a methodology that takes into account both of these bene ts, and show how optimal management decisions are altered in the presence of the indirect bene t of learning. We then apply this methodology to the case of controlling the Brown Treesnake (Boiga irregularis) on the island of Saipan. We nd that the indirect bene t—the value of information to reduce uncertainty—is likely to be quite large.

Inthe1990's,LittleFireAnts(LFAs)founditswaytotheislandofHawaii,mostlikelytravelingwithashipmentof potted plantsfrom Florida.These plants weresubsequentlysold toconsumers along theeastcoast of theIsland, alongwithLittleFireAntcolonieslivinginthepottingmedium.LFAisnowthrivingandcontinuestospread.Fifteenyearsaftertheinitialdetectionin1999,LFAhasspreadtoover4000locationsontheislandofHawaiiandhas beenfoundinisolatedlocationsonKauai,Maui,andOahuIslands.Currenteffortsareexpectedtocontaintheinfestations on the otherislands but signi cant additional investment isneeded tohalt therapid spread of LFA on the island of Hawaii. Increased management expenditures can suppress infestations; reduce spread between sectors; and decrease long-term management costs, damages, and stings.| Animmediateexpenditureof$8millioninthenext2–3yearsplusfollow-upprevention,monitoring,andmitigation treatments will yield $1.210 billion in reduced control costs, $129 million in lowered economic damages, 315 million fewer human sting incidents, and 102 million less pet sting incidents over 10 years.| Over35years,thebene tsinclude$5.496billioninreducedcontrolcosts,$538millionlesseconomicdamages, 2.161 billion fewer human sting incidents, and 762 million fewer pet sting incidents.

Economic impacts from invasive species, conveyed as expected damages to assets from invasion and expected costs of successful prevention and/or removal, may vary significantly across spatially differentiated landscapes. We develop a spatial-dynamic model for optimal early detection and rapid-response (EDRR) policies, commonly exploited in the management of potential invaders around the world, and apply it to the case of the Brown treesnake in Oahu, Hawaii. EDRR consists of search activities beyond the ports of entry, where search (and potentially removal) efforts are targeted toward areas where credible evidence suggests the presence of an invader. EDRR costs are a spatially dependent variable related to the ease or difficulty of searching an area, while damages are assumed to be a population dependent variable. A myopic strategy in which search only occurs when and where current expected net returns are positive is attractive to managers, and, we find, significantly lowers present value losses (by $270m over 30 years). We find further that in the tradeoff between search costs and damages avoided, early and aggressive measures that search some high priority areas beyond points of entry even when current costs of search exceed current damages can save the island more ($295m over 30 years). Extensive or non-targeted search is not advised however.

The botany of four small, relatively undisturbed tuff cone islands off the east coast of Upolu, Western Samoa, is examined. During a series of visits to the islands, the vegetation was studied in nine sample plots, and a checklist of the 260 species comprising the flora was compiled. Six types of native vegetation are recognized, one of which (Diospyros coastal forest) appears to be unique to tuff cone islands. Casual observations were made on the avifauna and turtle species, and the ecological significance of the islands is discussed.

Six archaeological sites up to 1000years old on Aitutaki, Cook Islands, have yielded bones of 15speciesof birds, five of which no longer occur ontheisland: Pterodromarostrata(Tahiti Petrel);Sula sula(Red-footedBooby); Dendrocygna,undescribedsp.(alarge,extinctwhistlingduck); Porzanatabuensis (Sooty Crake); and Vini kuhlii (Rimatara Lorikeet). Of these, only S. sula and P. tabuensis survive anywhere in the CookIslands today.The nearest record of anyspecies ofDendrocygnaisinFiji.Asidefrom theaquaticspeciesEgrettasacra (Pacific Reef-Heron) and Anas superciliosa (Gray Duck), the only native, resident land bird on Aitutakitoday isthe SocietyIslands Lorikeet(Viniperuviana), which may have been introduced from Tahiti. Residents ofAitutaki note that Ducula pacifica (Pacific Pigeon) and Ptilinopus rarotongensis (Cook Islands Fruit-Dove)also occurredthere until the 1940sor 1950s.There isno indigenous forest on Aitutaki today. The bones from Aitutaki also include the island's first record of the fruit batPteropus tonganus. Limestone caveson the island of Atiu yieldedthe undated bones of sixspeciesof birds, three of which no longer exist there or anywhere elsein the Cook Islands: Gallicolumba erythroptera (Society Islands Ground-Dove),Ducula aurorae (SocietyIslands Pigeon),and Vinikuhlii. Each of these specieshas been recovered from prehistoric sites on Mangaia as well. The limestone terrain of Atiu is mostly covered with native forest that supports populations of Ducula pacifica, Ptilinopus rarotongensis, Collocalia sawtelli(Atiu Swiftlet), and Halcyon tuta (Chattering Kingfisher). The survival of these land birds depends upon protection of Atiu's forests.

The giant African snail, Achatina fulica Bowdich, one of the most destructive molluscan pests of many tropical areas of the world, became established in Hawaii November 30, 1936. To control this pest predaceous snails, Gonaxis quadrilateralis (Preston), G. kibweziensis (E. A. Smith), and Euglandina rosea (Ferussac) were introduced. According the Davis, the population of A. Fulica has declined markedly in recent years and numerous empty shells have been observed in many areas of Oahu. Using these shells a demographic analysis was made in this study to determine the role of introduced predators on the biological control of this mollusk.