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.
The Baja California Pacifc Islands, Mexico, are globally important breeding sites for 22 seabird species and subspecies. In the past, several populations were extirpated or reduced due to invasive mammals, human disturbance, and contaminants. Over the past two decades, we have removed invasive predators and, for the last decade, we have been implementing a Seabird Restoration Programme on eight groups of islands: Coronado, Todos Santos, San Martín, San Jerónimo, San Benito, Natividad, San Roque, and Asunción.
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.
The Pacific Invasives Initiative (PII) is a sister partnership based at Auckland University which shares 6 partners with PILN. The goal of the PII is to contribute to conserving island biodiversity and enhancing the sustainability of island livelihoods by minimizing the spread and impacts of invasive species in the Pacific region. This is achieved by increasing support and developing capacity in the region for managing the impacts of these species.
Fishers have changed their methods from wading in the shallows to the use of sail and paddle canoes, and dinghies with outboard motors. This has resulted in greater coverage of the area where sea cucumbers live, more regular fishing, access to remote areas and the capacity to transport greater catches. Loss of much larger numbers of sea cucumbers from many areas as a result of this increased fishing pressure reduces the chances of adults remaining at densities high enough for effective reproduction.