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The electronic newsletter of the Pacific Invasives Learning Network (PILN)-reporting on invasives news from PILN teams and the Pacific region

The rose-ringed parakeet (RRP), Psittacula krameri, has become established in at least four Pacific Island countries (Hong Kong China, Japan, New Zealand, U.S.A.), including the Hawaiian islands of Kaua‘i, O‘ahu, and Hawai‘i. Most Pacific islands are at risk of RRP colonization. This species was first introduced to Hong Kong in 1903 and Hawai‘i in the 1930s–1960s, established since 1969 in Japan, and in New Zealand since 2005 where it has repeatedly established after organized removals. The founding birds were imported cage-birds from the pet trade. In native India, RRP are generally found associated with human habitation and are considered a severe agricultural pest. In the Hawaiian Islands, RRP are increasing and expanding their geographic ranges below 500m elevation. Population estimates in 2018 on Kaua‘i were ?6,800 birds, which was a three-fold increase and a 22.5% annual growth rate in the prior 6 years, whereas O‘ahu had ?4,560 birds with a 21% annual growth rate the prior 9 years; these rates suggest a population doubling time of ?3.5 years. Wild RRP can live 14+ years, can reproduce after 1.5 years, and have few effective predators. Breeding pairs produce 1–3 fledglings annually. RRP are seed predators and rarely seed dispersers; their flock-foraging behavior can result in severe damage to orchard and field agricultural crops including tropical fruit and corn (Zea mays), and such economic damages are especially pronounced on Kaua‘i. Island societies should prevent new introductions and consider RRP deterrents and population control methods to protect resources.

In 2012 a process was initiated to produce a guidance document for invasive species management on islands, as an objective of a regional invasive species project in the Western Indian Ocean (WIO) islands, implemented by IUCN. The consultative process for producing the document began with requests and discussions via regional and global island and invasives email distribution lists. Initial responses revealed a consensus on the need for a guidance document for programmatic planning. A draft was therefore constructed around existing Pacific regional guidelines and a draft manual that had initially been written for the WIO, with new supplementary sections suggested by respondents. The new draft was discussed and revised in workshops at two international conferences. The document is now organised into three main sections: the first on how to use it, the second a checklist of the essential components of a comprehensive island invasives programme (to ensure nothing is overlooked when planning), and the third providing detailed guidance on the planning and decision-making processes. The document is intended to provide a comprehensive framework and procedural guide for invasive species planning on islands. Further consultations took place by email, and a later draft was tested by a number of users writing various kinds of invasive species strategy and action plan. Publication will be in English, French (both published 2018) and Spanish (scheduled for 2019).

Invasive alien species represent one of the most significant threats to Arctic ecosystems and their inhabitants. Rapidly changing environmental conditions and a growing interest in resource extraction, settlement and tourism make the Arctic region particularly vulnerable to biological invasion. For this reason, invasive alien species are of substantial concern to the Arctic Council, a multi-national body comprised of Canada, the Kingdom of Denmark (including Greenland and the Faroe Islands), Finland, Iceland, Norway, Russia, Sweden, and the United States, as well as six international organisations that represent Arctic indigenous peoples as Permanent Participants. The Arctic Council’s Arctic Invasive Alien Species (ARIAS) Strategy and Action Plan includes the priority to: “actively facilitate the eradication of invasive alien species from island ecosystems throughout the Arctic, as well as the recovery of native island species and habitats that have been impacted by invasive alien species.” A multi-national team of governmental and non-government partners is collaborating in the development of an action plan (hereafter ‘islands plan’) for the eradication of invasive alien species from Arctic island ecosystems. The intent of the plan is to provide a vision and strategy for a region-wide approach to the eradication of island invasive alien species as a multi-national commitment. The islands plan will set forth a strategy for prioritising island eradications consistent with the growing pressures on ecological and cultural systems. We have a unique opportunity in the Arctic to take decisive action to prevent and mitigate the adverse impacts of invasive alien species that plague much of the rest of the world. The eradication of invasive alien species from islands in other parts of the world provides useful insights into best practices, including approaches to prioritisation and cost-effectiveness.

Recent years have seen large increases in the number and size of successful invasive species eradications from islands. There is also a long history of large scale removals on larger land-masses. These programmes for mammals and terrestrial plants follow the same cost-area relationship although spanning 10 orders of magnitude in scale. Eradication can be readily defined in island situations but can be more complex on larger land-masses where uncertainties defining the extent of a population, multiple population centres on the same land-mass and ongoing risks of immigration are commonplace. The term ‘complete removal’ is proposed to describe removal from an area with ongoing eff ort to maintain the area as clear, as features in many larger scale mainland programmes. Examples of complete removal to a boundary, in patches and in habitat islands are discussed. While island eradications continue to grow in scale, new legislation such as the lists of Species of European Union Concern will also drive increasing management on larger land-masses. However, these lists include large numbers of species that are already widespread. Methods are needed to prioritise species to reflect both the risks posed and the feasibility of management, including the effects of scale on cost and effectiveness.

Strengthening national and regional capacities to reduce the impact of Invasive Alien Species on globally significant biodiversity in the Pacific

Strengthening national and regional capacities to reduce the impact of Invasive Alien Species on globally significant biodiversity in the Pacific

The inhabited Isles of Scilly, 45 km off the south-western tip of the UK, are home to 13 seabird species including European storm petrel (Hydrobates pelagicus) and Manx shearwater (Puffinus puffinus), for which the UK has a global responsibility. Between 1983 and 2006, the overall seabird population in Scilly declined by c.25%. This decline triggered the establishment of the Isles of Scilly Seabird Recovery Project, a partnership with the aims to reverse seabird decline and engage the local community and visitors in conserving Scilly’s seabird heritage. The eradication of brown rats (Rattus norvegicus) from St Agnes and Gugh represented the result of over a decade of preparatory work, involving raising awareness and gaining 100% support from the community. The two islands are home to 85 people. Therefore additional, and somewhat unusual, preparations were required (including clearing sheds, communicating with school children and taking precautions to ensure the safety of pets) during the ground-based baiting operation. In 2016 St Agnes and Gugh were officially declared ‘rat-free’, meaning worldwide this is one of the largest community-based eradications to have been successful. Biosecurity on inhabited islands is complex, so to ensure the project’s sustainability, eff orts have been community-led. The community has taken ownership of protecting its seabirds, with 100% saying rat removal and the subsequent increase in seabirds has had, or will have, a positive effect on ecotourism, a key source of income for the islands. No less than 68% of the community said their businesses have directly benefited. This project represents a case study for other community-based projects, showcasing how eradications can gain community support and benefit both wildlife and human populations.

Invasive alien plants and animals are known for their disruption of ecosystems and threat to biodiversity. This book highlights their major impact on human health. This includes not only direct effects through contact with the species via bites, wounds and disease, but also indirect effects caused by changes induced in ecosystems by invasive species, such as more water hyacinth increasing mosquito levels and thereby the potential for malaria. Covering a wide range of case studies from different taxa (animals and plants), and giving an overview of the diverse impacts of invasive species on health in developed and developing countries, the book is a significant contribution that will help in prioritizing approaches to controlling invasive species and mitigating their health effects. It covers invasive plants, marine species, spiders and other arachnids, ticks and dust mites, insects, mosquitos and other diptera, freshwater species (invertebrates and fishes), amphibians and reptiles, birds and mammals.

Invasive snakes can lead to the rapid extinction of endemic vertebrates on insular ecosystems, usually because snakes are an efficient and novel predator. There have been no successful (i.e. complete) eradications to date of invasive snakes on islands. In this study we assess a novel invasion on Gran Canaria in the Canary Islands. The invader, the California king snake (Lampropeltis californiae), arrived from California via several generations in the pet trade. King snakes are captive bred for various phenotypes, and first were detected in the wild on Gran Canaria in the 1990s. Because very little natural history data exist from within their native range, we focused on developing datasets from native habitats to compare with similar data for the introduced snakes in the Canary Islands. We found that most aspects of the snake’s life history have not changed since invasion, except that there appears to be a lower level of juvenile recruitment along with an increase in the length and body mass of adult snakes on Gran Canaria. We identified environmental parameters for when capture/trapping could be completed to reduce eff ort and maximize success. Additionally, we show different trap success on the various life stages of the snakes. Risk assessments could be required prior to permitting pet trade or allowing captive bred snakes into regions where they are not native.