Enhancing the biosecurity of Pohnpei’s island ecosystems by putting together efforts to eradicate rats
Palau's National Invasive Species and Biosecurity Strategic Action Plan 2018-2022 describes goals, objectives, and actions for the National Invasive Species Committee (NISC) and associated members.
This NISSAP has been developed to identify invasive species and priority actions to address their threats on the environment, economy and livelihood of people.
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.
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
The world is facing a biodiversity crisis. Nowhere is that more apparent than on oceanic islands where invasive species are a major threat for island biodiversity. Rats are one of the most detrimental of these and have been the target of numerous eradication programmes; a well-established conservation tool for island systems.
Earths most highly threatened terrestrial insular vertebrates (111 of 1,184 species). Of these, 107 islands were in 34 countries and territories and could have eradication projects initiated by 2020. Concentrating efforts to eradicate invasive mammals on these 107 islands would benefit 151 populations of 80 highly threatened vertebrates and make a major contribution towards achieving global conservation targets adopted by the worlds nations.
Call Number: [EL]
Physical Description: 10 p.
The impacts of house mice (Mus musculus), one of four invasive rodent species in New Zealand, are only clearly revealed on islands and fenced sanctuaries without rats and other invasive predators which suppress mouse populations, influence their behaviour, and confound their impacts. When the sole invasive mammal on islands, mice can reach high densities and influence ecosystems in similar ways to rats.
Following the incursion of rats (Rattus rattus) on Taukihepa (Big South Cape Island; 93.9 km²) off southern New Zealand in 1963, and the subsequent extirpation of several endemic species, the New Zealand Wildlife Service realised that, contrary to general belief at the time, introduced predators do not reach a natural balance with native species and that a safe breeding habitat for an increasing number of at risk species was urgently needed.
Rat eradication is a highly effective tool for conserving biodiversity, but one that requires considerable planning eff ort, a high level of precision during implementation and carries no guarantee of success. Overall, rates of success are generally high but lower for tropical islands where most biodiversity is at risk. We completed a qualitative comparative review on four successful and four unsuccessful tropical rat eradication projects to better understand the factors influencing the success of tropical rat eradications and shed light on how the risk of future failures can be minimised.
In June/July 2002 an eradication programme to remove Pacific rats from Maninita Island in the Vava'u group of the Kingdom of Tonga was initiated. The techniques used were similar to those
used in successful rat eradications in New Zealand, in that Pestoff 20R pellets and a network of bait stations were used.
Conditions on the island were not what was expected, the forest having been adversely affected by cyclone Waka and subsequent defoliation by caterpillars, resulting in an open forest canopy. Rats were found to be present on the island in high numbers and were breeding.
In June/July 2002 the eradication of Pacific rats from Maninita Island in the Vava'u group of the Kingdom of Tonga was attempted using Brodifacoum pellets in bait stations. In December 2002, Maninita was revisited and rat trapping carried out to determine if rats were present. While no rats were caught and none were seen, further monitoring in June 2003 is recommended before the island is declared "rat free '.
For one of the species potentially at some risk of poisoning under the proposed rat eradication regime, the Friendly Ground Dove, Nuutele and Nuulua hold populations that are nationally significant. The complete loss of these populations would threaten the survival of the taxon in Samoa. Some authors consider the Samoan doves to be a separate race (Gallicolumba s. stairi) from those in Fiji and Tonga (Watling, 2001). Outside Samoa, the race is only found on the small island of Ofu,
The islands of Nu'utele and Nu'ulua have been identified as highly significant sites for conservation in Samoa. They hold large populations of species currently found nowhere else in the country' including threatened land-birds, seabirds and nesting
turtles. They also are the only offshore islands large enough and far enough offshore to be considered as refuges for several of the nation's species threatened on the larger islands by introduced mammalian pests. Such refuges have assumed greater
The restoration of the Islands of Nuutele and Nuulua is a priority of the Government of Samoa and the communities of Aleipata District. Planning is well advanced on a key element of this, the eradication of Pacific Rats (Rattus exulans) by aerial
spreading of toxic baits in mid-2006. The Friendly Ground Dove has been identified as a non-target species that may be at risk of taking the baits and one for which the Nuutele and Nuulua populations are significant. Several approaches for safeguarding