Eradication of invasive rodents has become a powerful tool to protect native island biota. Use of brodifacoum, an anticoagulant rodenticide, has contributed to hundreds of successful invasive rodent eradication e?orts on islands. Application of bait containing brodifacoum for this purpose requires appropriate consideration of adverse e?ects on non-target wildlife. Thus, a priori identi?cation of non-target risks and, where needed, approaches to mitigate these to acceptable levels, is now an essential component of eradication planning and implementation. As part of the plan for eradicating invasive rats and mice from Floreana Island in the Galapagos, we experimentally tested the e?ect of brodifacoum on the Galapagos endemic land snail species Naesiotus unifasciatus. Importantly, the trials were designed to evaluate e?ects of particular components of the bait pellets, namely the active brodifacoum, the pyranine biomarker, and a blue dye. We found no evidence for increased snail mortality following exposure to any of these bait components. We review results of past toxicity studies on terrestrial molluscs and ?nd that, as for our own study, there is likely to be little impact of anticoagulant rodenticide on terrestrial mollusc survival as the result of application of brodifacoum bait. However, given the limited taxonomic representation in the toxicity tests performed on terrestrial molluscs so far, we recommend the continued used of captive toxicity trials to assess potential e?ect of any rodenticide applications on native malacological fauna on a case-by-case basis where large-scale eradication programmes are planned and undertaken.
Short website news article about rat eradication on Chagos Islands in the Indian Ocean and how bird populations increase without rat predation increasing nutrients from bird guano into the coral reefs; cites letter article in Springer Nature - Seabirds enhance coral reef productivity and functioning inthe absence of invasive rats, Nichaolas A.J. Graham, Shaun K. Wilson, Peter Carr, Andrew S. Hoey, Simon Jennings, M. Aaron MacNeil https://doi.org/10.1038/s41586-018-0202-3
Invasive species pose an enormous threat in the Pacific: not only do they strongly affect biodiversity, but they also potentially affect the economic, social, and cultural wellbeing of Pacific peoples. Invasive species can potentially be managed and that their impacts can potentially be avoided, eliminated, or reduced. However, neither the costs nor the numerous benefits of management are well understood in the Pacific. Thus, the goals of this project were: A) to account for both the costs and benefits of managing invasive species; B) to prepare empirically grounded advocacy materials to help increase investment in the management of invasive species; C) to help governments prioritise investment in managing these species; and D) to build capability for undertaking economic assessments in the future. To accomplish these goals, we undertook cost-benefit analyses (CBAs) of managing five species that are well established on Viti Levu, Fiji: spathodea campanulata (African tulip tree), herpestus javanicus (small Asian mongoose), papuana uninodis (taro beetle),
pycnonotus cafer (red-vented bulbul), and merremia peltata (merremia vine). Next, we conducted a comprehensive training programme on the CBA for invasive species management for professionals from the Pacific. Third, we collaborated with Pacific organisations to develop a uniform guide to conducting CBAs with numerous examples from the region. We also designed a flexible Microsoft Excel-based tool for conducting CBAs, enabling professionals who did not attend the training course to nevertheless undertake rigorous CBAs on invasive spsecies management. Finally, we developed advocacy material and publicised findings from this project to promote investment in invasive species management. This report details these activities in turn. It also includes numerous appendices that include the tools, guidance documents, and advocacy materials developed under this project.
Invasive alien mammals are the major driver of biodiversity loss and ecosystem degradation on islands. Over the past three decades, invasive mammal eradication from islands has become one of society's most powerful tools for preventing extinction of insular endemics and restoring insular ecosystems. As practitioners tackle larger islands for restoration, three factors will heavily influence success and outcomes: the degree of local support, the ability to mitigate for non-target impacts, and the ability to eradicate non-native species more cost-effectively. Investments in removing invasive species, however, must be weighed against the risk of reintroduction. One way to reduce reintroduction risks is to eradicate the target invasive species from an entire archipelago, and thus eliminate readily available sources. We illustrate the costs and benefits of this approach with the efforts to remove invasive goats from the Galápagos Islands. Project Isabela, the world's largest island restoration effort to date, removed >140,000 goats from >500,000 ha for a cost of US$10.5 million. Leveraging the capacity built during Project Isabela, and given that goat reintroductions have been common over the past decade, we implemented an archipelago-wide goat eradication strategy. Feral goats remain on three islands in the archipelago, and removal efforts are underway. Efforts on the Galápagos Islands demonstrate that for some species, island size is no longer the limiting factor with respect to eradication. Rather, bureaucratic processes, financing, political will, and stakeholder approval appear to be the new challenges. Eradication efforts have delivered a suite of biodiversity benefits that are in the process of revealing themselves. The costs of rectifying intentional reintroductions are high in terms of financial and human resources. Reducing the archipelago-wide goat density to low levels is a technical approach to reducing reintroduction risk in the short-term, and is being complemented with a longer-term social approach focused on education and governance.
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 rodent pest community is known, but the type and scales of damage to different crops on different islands are unknown. Knowledge about rodent pest management in other geographical regions may not be directly transferable to the Pacific region. Many studies on islands have largely focussed on the eradication of rodents from uninhabited islands for conservation benefits. These broadscale eradication efforts are unlikely to translate to inhabited islands because of complex social and agricultural issues. The livelihoods, culture and customs of poor small-scale farmers in the South Pacific have a large bearing on the current management of rodents. The aim of the present review was to describe the rodent problems, impacts and management of rodents on South Pacific islands, and identify gaps for further research. We compared and contrasted two case studies. The situation in Papua New Guinea is emergent as several introduced rodent species are actively invading new areas with wide-ranging implications for human livelihoods and conservation. In Vanuatu, we show how rodent damage on cocoa plantations can be reduced by good orchard hygiene through pruning and weeding, which also has benefits for the management of black pod disease. We conclude that (1) damage levels are unknown and unreported, (2) the impacts on human health are unknown, (3) the relationships between the pest species and their food sources, breeding and movements are not known, and (4) the situation in Papua New Guinea may represent an emergent crisis that warrants further investigation. In addition, there is a need for greater understanding of the invasive history of pest rodents, so as to integrate biological information with management strategies. Ecologically based rodent management can be achieved on Pacific Islands, but only after significant well funded large-scale projects are established and rodent ecologists are trained. We can learn from experiences from other locations such as Southeast Asia to guide the way.
New Zealand, an archipelago of more than 2000 islands, has a terrestrial fauna especially depauperate in native land mammals. Kiore (Rattus exulans) was the first of four rodent species introduced by people. A project to eradicate invasive rats from Kapiti Island in 1996, represented a turning point in the technology, complexity and scale at which managers of natural heritage on New Zealand islands could operate. This paper includes case studies of some significant projects targeting rodents, sometimes with other introduced mammals, undertaken in the 12 years following Kapiti. Details of the methods, costs, results and outcomes are provided for Kapiti, Whenua Hou, Tuhua, Campbell, Raoul, Hauturu, Taukihepa, and Pomona islands, collectively representing a total of over 23,000 ha of habitat cleared of introduced mammals. Research and trials undertaken in the Kapiti project provided the basis for future environmental risk assessments, allowing other projects to focus on knowledge gaps. New trends in invasive species eradication in New Zealand include more challenging multi-species eradication projects, some of which are undertaken by self- funded community groups. To summarise the lessons of the New Zealand experience: a programmatic approach is recommended which will fit each eradication within a context or framework of goals for those islands; address biosecurity issues at the outset; build capability to attempt the most challenging and rewarding projects; facilitate investment in monitoring and manage expectations of stakeholders to ensure their ongoing support. Success breeds success but is never guaranteed.
Big South Cape Island (Taukihepa) is a 1040 ha island, 1.5 km from the southwest coast of Stewart Island/Rakiura, New Zealand. This island was rat-free until the incursion of ship rats (Rattus rattus) in, or shortly before, 1963, suspected to have been accidentally introduced via local fishing boats that moored at the island with ropes to the shore, and were used to transport the mutton birders to the island. This incursion was reported by the muttonbirders local Iwi who harvest the young of titi (sooty shearwater, Puffinus riseus) to the then New Zealand Wildlife Service (via the New Zealand Department of Lands and Survey). Investigation into the reports found ship rats had reached the island and had decimated the local land bird populations. Brian Bell and Don Merton attempted some of the first translocations of South Island saddleback (Philesturnus c. carunculatus), Stewart Island snipe (Coenocorypha aucklandica iredalei) and Steads bush wren (Xenicus longipes variabilis) with only the saddleback being successful. Extinctions of the snipe, wren and greater short-tailed bat (Mystacina robusta) were recorded. This was the first time rats were definitively recognised as the cause of extinction of native land birds and directed further debate into the impacts of rats and how to deal with them.
BBC website news article - Flood hit South Indian state of Kerala 11 people died of leptospirosis; After floods expect to see water-borne diseases like cholera, typhoid, diarrhoea, hepatitis and rat fever
This review of the invasive land vertebrates present on islands of the South Pacific Regional Environment Programme (SPREP) region is part of a larger review of the invasive plants and animals that have affected these islands adversely.
Think of a challengeing conservation problem you have encounteres - protecting a rare species, winning support for legislation, cleaning up a river, or sustainably managing a forest.|Presentation given in the 3rd Vertebrate Pest Conference, Preceedings collect of Conference includes this wich speaks of broad impacts of rats on Eniwetok Atoll in the Marshall Islands.