After an invasive species arrives in a new place, it needs to survive and reproduce, establish a population, and spread, before impacts are noticed. By the time impacts are obvious, the control or eradication of invasive species can be difficult and expensive or sometimes impossible. The purpose of this programme is to prevent or detect the arrival of invasive species and stop their establishment, spread and impacts.

Biodiversity is the foundation of all healthy ecosystems but, on many Pacific islands, invasive species are destroying native plants and animals, causing entire ecosystems to collapse. Removing invasive predators such as rats is a nature-based solution that can help to restore the resilience of island ecosystems by supporting the return of seabird populations and the vital nutrients they provide for forest systems and coral reefs. We know that on islands without rats the coral reef systems can provide up to 50% more fish for local communities. Island Conservation, the lead for the Predator Free Pacific programme, is supported by key PRISMSS partners including BirdLife International and the New Zealand Department of Conservation. Together these organizations have now eradicated invasive predators from over 60 Pacific islands. The growing success of the Predator Free Pacific programme is based on combining global eradication expertise with local knowledge and efforts to build greater community awareness and ownership of the ongoing benefits of restoring the resilience of island ecosystems.

Some invasive plants have the ability to transform (damage or destroy) ecosystem function. Weeds outcompete more desirable plant species and disrupt processes such as water flow, fire regimes, soil quality, nutrient cycling and regeneration. Weeds can also be harmful to human and animal health. Weeds thrive on disturbance and so their harmful impacts are exacerbated by tropical cyclones, strong winds, drought and fires, all of which are increasing in severity due to the changing climate. Whilst there are several existing weed management programmes across the Pacific, capacity overall is very limited. This programme is focused on the management of high risk, low distribution weed species, where the objective is eradication or containment.

Pacific threatened species and ecosystems often exist within high value areas on larger islands where invasive animals and invasive plants will continue to be a threat. A site-led approach to manage multiple invasive species and re-introduce lost native species and ecosystem structure over a longer period of time is the last remaining option to restore and maintain these ecosystems. Communities directly benefit from resilient ecosystems and are an essential part of ecological restoration. Many priority area ecosystems have been restored over the past 3 decades, mostly in New Zealand. The Pacific has had several pilot sites which have had very successful outcomes with increases in threatened endemic birds.