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Considerable bene?ts can be achieved for indigenous biodiversity when invasive vertebrates are removed from islands. In New Zealand, two logistically challenging eradications were undertaken, one to remove cats (Felis catus) and the other Paci?c rats (Rattus exulans) from Te Hauturu-o-Toi/Little Barrier Island (Hauturu). Here we document the short- and long-term impacts of these interventions on the biodiversity of Hauturu. We also assess the extent to which predicted outcomes were re?ected in the measured responses for a wide range of species. Short-term impacts of the eradication program encompassed individual mortality for some native species but no measurable impact to populations. In contrast, at least 11 native vertebrates and one native invertebrate species increased in abundance after rat and cat removal. Fifteen of 34 plant species monitored had signi?cantly more seedlings on Hauturu after rat eradication compared with control islands, indicating future changes in forest composition. Several native species previously not recorded on the island were discovered, including the New Zealand storm petrel (Fregetta maoriana) (formerly considered extinct), the forest ringlet butter?y (Dodonidia helmsi) and eight species of aquatic invertebrate. The chevron skink (Oligosoma homalonotum) has been found in increasing numbers and tuatara (Sphenodon punctatus), raised in captivity on the island, are now re-established and breeding in the wild. These results illustrate an island gradually recovering after a long period of modi?cation. We conclude that more success stories such as Hauturu must be told if we are to allay the public’s concerns about such eradication campaigns. And more public support is required if the conservation community is to tackle invasive species at a scale commensurate with the threats they pose.

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.

A successful ground-based eradication of black rats (Rattus rattus) was undertaken on the remote, uninhabited Shiant Isles of north-west Scotland over winter (14 October–28 March) 2015–16. The rat eradication was carried out as part of the Shiants Seabird Recovery Project, which aims to secure long-term breeding habitat for protected seabirds and to attract European storm petrels and Manx shearwaters to nest on the Shiants. Throughout the eradication operation, teams were stationed on two of the three main Shiant islands (Eilean an Tighe, Eilean Mhuire), with access to the third (Garbh Eilean) via a boulder causeway from Eilean an Tighe. Bait (Contrac® blocks containing the anticoagulant bromadiolone 0.005% w/w), was deployed in a grid of 1,183 bait stations covering all areas of the islands and sea stacks. Bait stations were set 50 m apart, with intervals reduced to 25 m in coastal areas of predicted high rat density. Difficult areas were accessed by boat and cliff s of ~120 m in height were accessed by abseiling down ropes made safe using either bolted anchors or ground stakes. The team of staff and volunteers worked through difficult conditions, deploying bait and monitoring intensively for any surviving rats using a combination of tools. The islands were declared rat free in March 2018. This ambitious and challenging project has greatly enhanced UK capacity in rodent eradications for the purposes of conservation.

As part of the Isles of Scilly Seabird Recovery Project, and directed by Wildlife Management International Ltd, the eradication of brown rats (Rattus norvegicus) from the inhabited islands of St Agnes & Gugh, Isles of Scilly was completed between October 2013 and April 2014 with the assistance of volunteers, and staff from the Royal Society for the Protection of Birds, Isles of Scilly Wildlife Trust and Natural England. Bait stations with cereal-based wax blocks containing bromadiolone at 0.005% w/w were established on a 40–50 metre grid over the island. With the presence of 85 residents on the 142 ha islands, this is the largest community-based brown rat eradication globally to date. Given the fact that a community is based on these islands, community engagement and advocacy was a vital and fundamental part of the eradication. Consultation for eradication began three years prior to the operation to explain the requirements for the proposed project and to assess support, but this built on many years of wider community engagement with seabird conservation. All of the residents supported the eradication of rats and vision of the project. The consultation and inclusion of the community in decision-making and management of the Isles of Scilly Seabird Recovery Project was a critical part of the operation and key to the success of the eradication. The community took ownership of the project and has committed to the on-going biosecurity requirements following the eradication of rats. The removal of brown rats from St Agnes and Gugh was a major achievement and provided the opportunity to restore the islands' communities of seabirds and other native species. This project provided an example of the effectiveness of ground-based rodent eradication techniques on an inhabited island and the lessons learnt during this operation can be used to help proposed eradications on other islands with communities and with terrain suitable for ground-based techniques.

Rat eradication techniques developed in New Zealand are a proven method for removing invasive rodents from islands worldwide. This technology moved rapidly from ground-based bait station operations to aerial application of rodenticides. Rat eradications on tropical islands using similar methods, have not always been as successful as those in temperate regions. As most previous eradications in the Caribbean have been on islands smaller than 50 ha, the eradication of black rats (Rattus rattus) from 207 ha Dog Island was a significant increase in size. Reptile and seabird populations on Dog Island had been in decline for a number of years and black rats were identified as the most likely factor. Following the feasibility study in 2007, the Dog Island Recovery Project was launched in 2011. This was a multiple-year project incorporating a ground-based eradication with establishment of biosecurity procedures to prevent reinvasion, alongside long-term monitoring of native species. Bait stations with cereal-based wax blocks containing brodifacoum at 0.005% w/w were established on a 30–50 m grid over the island. Interference with bait stations by non-target invertebrates, particularly crabs, was high and bait stations required moving or elevating to avoid this. However, there was no evidence of any non-target animals being killed or injured by the bait. Eradication success was confirmed in 2014.

The inextricable links between climate change and sustainable development have been increasingly recognised over the past decade. In 2007, the Intergovernmental Panel on Climate Change (IPCC)1 concluded with very high confidence that climate change would impede the ability of many nations to achieve sustainable development by mid-century and become a security risk that would steadily intensify, particularly under greater warming scenarios. Article 4.8 of the United Nations Framework Convention on Climate Change (UNFCCC) lists several groups of countries that merit particular consideration for assistance to adapt to climate change “especially: (a) small island countries, (b) countries with low-lying coastal areas, c) countries with areas prone to natural disasters.” Small Island Developing States (SIDS) have characteristics which make them particularly vulnerable to the effects of climate change, sea level rise (SLR) and extreme events, including: relative isolation, small land masses, concentrations of population and infrastructure in coastal areas, limited economic base and dependency on natural resources, combined with limited financial, technical and institutional capacity for adaptation.2

The nations of CARICOM16 in the Caribbean together with Pacific island countries contribute less than 1% to global greenhouse gas (GHG) emissions (approx. 0.33%17 and 0.03%18 respectively), yet these countries are expected to be among the earliest and most impacted by climate change in the coming decades and are least able to adapt to climate change impacts. These nations’ relative isolation, small land masses, their concentrations of population and infrastructure in coastal areas, limited economic base and dependency on natural resources, combined with limited financial, technical and institutional capacity all exacerbates their vulnerability to extreme events and climate change impacts. Stabilising global GHG emissions and obtaining greater support for adaptation strategies are fundamental priorities for the Caribbean Basin and Pacific island countries. CARICOM leaders recently unveiled their collective position that global warming should be held to no more than 1.5°C19 and continue to develop a Climate Change Strategic Plan. The Pacific island countries have expressed their priorities for addressing climate change regionally through the Pacific Leaders’ Call to Action on Climate Change20 and the Pacific Islands Framework for Action on Climate Change 2006-2015.21