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In July 2016, the European Union adopted a list of invasive alien species of concern, and at present there are two freshwater ?sh species on the list. Member states are obliged to prevent further spread and to perform rapid eradication when problem species are discovered at new sites, but continental EU member states have limited experience with eradication of ?sh. Eradications are more likely to succeed if the invasive species is con?ned to insular habitats. Freshwater invasives can be regarded as island invasives, since their habitats have boundaries against shorelines, saline waters, waterfalls and dams, and these boundaries make eradications possible. CFT Legumine® containing rotenone is the only legal piscicide in the EU, and Norway has used CFT Legumine® in eradication e?orts for many years. Species that have been introduced outside their native range and have been successfully eradicated include minnow (Phoxinus phoxinus), roach (Rutilus rutilus), pike (Esox lucius), common white?sh (Coregonus lavaretus), and the salmon parasite Gyrodactylus salaris. This manuscript summarises the eradication e?orts of invasive ?sh species and ?sh parasite species during the last two decades in Norway, covering eradications from such diverse habitats as small ponds, lakes, marshlands, small streams and large rivers. An estimated £100 million has been spent in the Gyrodactylus salaris eradication programme. Costs of invasive ?sh eradications are given, ranging from less than £10,000 to more than £200,000. There are no known invasive ?sh eradication failures in Norway in the last 20 years. A summary of the e?orts in Norway can be an aid for planning control and eradication measures of invasive ?sh species in other countries.

Invasive species are of signi?cant concern, especially in mega-diverse countries, because they cause negative e?ects such as loss of native biodiversity, ecological alterations, disease spread, and impacts on economic development and human health. In mainland Ecuador, information on invasive invertebrates in marine ecosystems is scarce. The objective of this study was to describe and locate the invasive species present in the rocky shores of the intertidal and subtidal zones along 10 areas (83 sites) covering most of the Ecuadorian coast during 2015–2016. Benthic macroinvertebrates communities were measured over quadrats located randomly on a 50 m transect positioned parallel to the coast in the intertidal and subtidal zone, covering an area of 1,860 km2. Six invasive species were recorded: Arthropoda (Amphibalanus amphitrite), Cnidaria (Pennaria disticha, Carijoa riisei), Bryozoa (Bugula neritina), Rhodophyta (Asparagopsis taxiformis) and Chlorophyta (Caulerpa racemosa). The areas with highest abundance of invasive species were in Jama (not a protected area), Marine and Costal Wildlife Reserve Puntilla of Santa Elena and Santa Clara Island Wildlife Refuge (protected areas). The most abundant species was Carijoa riisei with a relative abundance of up to 80%. It was the most aggressive of the invasive species registered in the subtidal zone, mainly in northern centre of the Ecuadorian coast. C. riisei is growing on native coral (Pocillopora spp.) and on sessile macroinvertebrate communities (Pinctada mazatlanica, Muricea appresa and Aplysina sp.) that are being a?ected by its invasion. This study must be taken into account by local and regional government authorities to create public policy programmes of monitoring for surveillance and control of invasive species. These programmes should focus on integration of socio-economic and ecological e?ects. They should be complemented by experimental design and analysis of environmental variables to provide technical information for a baseline of bio-invasion analysis along the Ecuadorian coast and Galápagos, to avoid the expansion of invasive species negatively a?ecting the marine biodiversity of mega-diverse countries such as Ecuador and other countries of South America.

Prior to 2008 there were few invasive alien species (IAS) initiatives operating in Scotland on a scale required for e?ective control. The establishment of the Biosecurity and Invasive Non-Native Species Programme by the Rivers and Fisheries Trusts of Scotland was the ?rst attempt to link local e?orts with national IAS strategy on scales appropriate to the e?ective control of target species. The programme worked with 26 local ?sheries trusts to produce biosecurity plans that covered over 90% of Scotland’s rivers and lochs. The programme implemented a range of prevention measures, including promoting awareness of invasive species issues and the need for biosecurity among water users. Projects were established for invasive plants on most major river systems, and for American mink (Neovison vison) in the north of Scotland. These projects involved public/private partnerships, using a mix of professional sta? and volunteers. Interactive data management systems were developed to manage input from a large number of individuals and to inform an adaptive management approach. These control projects demonstrated that it is feasible to reduce the size and density of target populations of invasive species across large geographic areas. The key to maintaining the momentum of this control e?ort in the future will be to demonstrate sustainable IAS management in the longer term. This challenge led to the formulation of the Scottish Invasive Species Initiative (SISI) whose overall aim is the development of a long-term, cost-e?ective strategy for IAS management throughout the north of Scotland. SISI will test strategies derived from experience and information from previous control projects. Important areas that the initiative will seek to address include de?ning outcomes, integrating IAS management into other management initiatives, and maintaining partnership interest and cohesiveness in a challenging funding environment.

St. Helena Island, 122 km2 (47 sq. miles) is a UK Overseas Territory in the South Atlantic. It is a remote volcanic island situated in the sub-tropics 1,127 km (700 miles) from Ascension Island and 2,736 km (1,700 miles) from South Africa. Its resident population of ca. 4,500 is serviced by a single supply ship which visits up to 25 times a year. Isolation has acted historically as a natural barrier to pest arrival and border control has followed the conventional practice of protecting agricultural interests through restrictions on fresh produce, plant materials, livestock and pets. The bene?ts of isolation were compromised in 2016 when the ?rst airport opened. Private jets arrive now from Africa, Europe and South America, and commercial ?ights started at the end of 2017. A programme of biosecurity capacity building and strengthening was established in anticipation of this air tra?c. St Helena authorities introduced a national biosecurity framework and associated policy (entitled Biosecurity St Helena), the latter constructed through multi-sectoral consultation, and key stakeholders participated throughout in policy development. Biosecurity St Helena applies international standards set by the International Plant Protection Convention across the biosecurity continuum. As is typical in small island nations, human and ?nancial resources are limited, so that the biosecurity strategy addresses mainly higher risks. Compliance is heavily reliant on public awareness. Active communication engages all community sectors in biosecurity work through education, information, advocacy and feedback. Authorities use key performance indicators to measure the e?ectiveness of this approach. Biosecurity St Helena is a model of actively socialised biosecurity for other small island nations.

The invasive tree Miconia calvescens (Melastomataceae) is a priority for control on the Hawaiian Island of O?ahu due to its potential to replace native ??hi?a (Metrosideros polymorpha, Myrtaceae) forests and degrade watershed function if allowed to establish. The O?ahu Invasive Species Committee (OISC) is attempting to eradicate this species from the island of O?ahu. OISC uses a bu?er strategy based on estimated seed dispersal distance to determine the area under surveillance. This strategy has worked well enough to suppress the number of trees reaching reproductive age. The number of mature trees removed annually is now less than the number initially removed when the programme started in 2001. In 2016, just 12 mature trees were removed from 54.71 km2 surveyed compared to 2002, when 40 mature trees were removed from 8.26 km2 surveyed, a 96% drop in mature trees per square kilometre surveyed. However, miconia has a long-lived seed bank and can germinate after 20 years of dormancy in the soil. Funding shortages and gaps in surveys due to refusal of private property owners to allow access have resulted in some long-range extensions. OISC’s results suggest that seed bank longevity is an important factor when prioritising invasive species risk and that allocating more resources at the beginning of a programme to eradicate a species with long-lived seed banks may be a better strategy than starting small and expanding.

During the 45 years that the Raoul Island weed eradication programme has been underway, eleven species have been eradicated. To complete the restoration of Raoul Island’s unique ecosystems supporting signi?cant seabird biodiversity and endemic biota, nine further transformer weeds must be eradicated. In this review of progress to date, we examine the feasibility of eradication of these transformers and identify that four species are on target for eradication: African olive (Olea europaea subsp. cuspidata), yellow guava (Psidium guajava), castor oil plant (Ricinus communis) and grape (Vitis vinifera). However, for four more species more sta? resources are required to achieve eradication as currently infestations are establishing faster than they are being eliminated: purple guava (Psidium cattleianum), black passionfruit (Passi?ora edulis), Brazilian buttercup (Senna septemtrionalis) and Mysore thorn (Caesalpinia decapetala). The ninth species, Madeira vine (Anredera cordifolia), is being contained but presents logistical di?culties for e?ective control – herbicide resistant tubers and cli? locations requiring rope access in unstable terrain. Increasing the resources for this programme now to enable eradication of these transformer weeds will reduce the total long-term cost of the programme. Eradication of rats, the 2006 eruption, recent greater cyclone frequency, increased tourism requiring biosecurity management, and sta?ng reductions have all impacted progress on weed eradication. Myrtle rust (Austropuccinia psidii), con?rmed in March 2017 as the latest invasive species on Raoul Island, is establishing on Kermadec pohutukawa (Metrosideros kermadecensis), the dominant canopy species. The impact of this species on the weed eradication programme is unknown at this point.

The North American signal cray?sh (Pacifastacus leniusculus) has been present in Scotland since at least 1995 and the species is now known to be present in a number of catchments. Once established, few opportunities for containment exist and eradication can often be impossible to achieve. However, in small, isolated water bodies, the application of a non-cray?sh-speci?c biocide has provided the opportunity to remove this species permanently. In July 2011, signal cray?sh were discovered in a ?ooded quarry pond at Ballachulish in the Scottish Highlands. This is an isolated site located ~100 km from the nearest known population and it is likely that the population was established as the result of a deliberate release of these animals 10 years previously. Experience gained from using the eradication technique at other sites in the UK led to the site being treated with a natural pyrethrum biocide (Pyblast®) in June 2012. Post treatment monitoring from 2012–2017 indicates that eradication has been successful. Monitoring of native species a?ected by the biocide suggests that both invertebrates and amphibians quickly recolonised the quarry pond. Eradication of cray?sh using biocide is only feasible in water bodies where the entire population of cray?sh can be exposed to a lethal dose and the impact on non-target species can be accepted. The technique is not appropriate for large, connected water bodies, although it may be possible to treat short stretches of canals where biocide exposure can be controlled and isolated populations of cray?sh can be e?ectively treated.

The South Georgia ecosystem-based habitat restoration project is a major project that began with the eradication of invasive rats (Rattus norvegicus) and reindeer (Rangifer tarandus), 2011–2017. As part of this restoration programme a non-native plant management strategy was developed and implemented. With only 8% of the whole South Georgia landmass suitable for vascular plants (ca. 283 km²) due to permanent ice and bare rock, there have been 25 indigenous vascular plants and 41 non-native plants recorded from earlier surveys. Following removal of grazing pressure from introduced mammals, surveys were conducted to quantify the current status and distribution of non-native plant populations and enable a non-native plant control strategy to be developed for the island. Due to the vast scale of the island, multiple seasons were required to carry out rapid surveys of key indicators such as species, area of plant coverage in square metres and age class (mature or juvenile). Survey and control data were entered into a spatial database to enable analysis, allow data-informed management decisions and be used for long-term control-based monitoring of outcomes. During this series of surveys, 44 naturalised, non-native plant species were identi?ed and mapped. Of these, 34 species are now being managed at zero density with 56,851 m2 at 184 sites controlled to date; four are managed at speci?c sites with 22,443 m2 controlled to date, three require con?rmation of species and the remaining three species are widely established and receive limited control. Spatially quantifying the distribution and control of non-native plants has enabled the development and implementation of an e?ective management strategy which contributes to the restoration of South Georgia’s native biodiversity.

Biological invasions are one of the major threats to biodiversity, especially on islands where the number of endemic species is the highest despite their small area. In the Canary Islands, the relationships among invasive alien species (hereafter IAS) and their environmental and anthropogenic determinants have been thoroughly described but robust provisional models integrating species spatial autocorrelation and patterns of IAS communities are still lacking. In this study, we developed a Generalised Linear Spatial Model for Invasive Alien Species Richness (IASR) under a Bayesian framework, using a methodological approach that encompass GIS and geostatistical analysis. In this study, we hypothesised that the inclusion of spatial autocorrelation can improve model performance thus obtaining more IASR-reliable predictions. In addition, this method provides uncertainty maps that prioritize areas where further sampling e?orts are needed. Our model showed that IASR in Tenerife is mainly driven by a combination of anthropogenic and natural processes, highlighting favourable conditions for IAS from the coastline to about 800 m a.s.l., especially on the windward humid aspect. Among anthropogenic factors, a clear positive relationship between road kernel density estimation and IASR was found. Indeed, road density has recently increased especially in low to mid altitudinal zones on the Canary Islands, strictly associated with urban expansion and it has been widely demonstrated to be one of the main IAS pathways. Hence, higher road density can be related to increased ‘propagule pressure’ which is, together with source of disturbance, one of the most important factors explaining richness in alien species invasion success. Our main conclusions highlight the importance of considering spatial autocorrelation and researchers’ prior knowledge to increase the predictive power of statistical models. From a practical perspective, these models and their related uncertainty, will serve as important management tools highlighting those portions of territories that will be more prone to biological invasions and where monitoring e? orts should be directed.

Invasive alien ornamental plants are a global problem, especially on oceanic islands, and can have severe impacts on native biodiversity. Pinanga coronata, is an ornamental palm tree that can form mono-dominant stands in its native habitat and is widely cultivated throughout the tropics. Here we investigate the introduction, spread, impact and management of this invasive palm in the Fiji Islands, using extensive discussions with local experts and ?eld surveys. Pinanga coronata was introduced in the 1970s to the Colo-i-Suva area, eastern Viti Levu island, Fiji´s principal island, and has since become invasive in mahogany plantations and lowland rainforest. It has also been introduced and is becoming invasive on the western side of that island. However, the distribution of P. coronata remains geographically limited to the immediate vicinity of introduction sites but it is rapidly spreading. In each location, the species has formed mono-dominant stands in the understorey and appears to be displacing native plant species, as suggested by a negative correlation of its abundance with that of native tree ferns. This highlights the need for rapid control of P. coronata in Fiji. Local experts state management should involve manual removal of seedlings and saplings, killing of adult palms by injection of herbicide, and education and legislation to prevent the further spread of the species. Based on these recommendations and ?eld data, management actions to control P. coronata are proposed and steps to develop these into a management plan are discussed. Given P. coronata threatens native biodiversity in Fiji and has the potential to invade other rainforest ecosystems in the tropics, proposed management approaches are urgent and relevant for other tropical countries.