Invasive alien species are one of the primary threats to native biodiversity on islands worldwide, and their expansion continues due to global trade and travel. Preventing the arrival and establishment of highly successful invasive species through rigorous biosecurity is known to be more economic than the removal of these species once they have established. However, many islands around the world lack biosecurity regulations or practical measures and establishing biosecurity will require social and financial investments.

Invasive species (non-native, harmful organisms) undermine human health and safety, food and water security, and economic development. Consequently, invasive species can have significant socio-economic impacts and warrant attention as a public policy priority. Trade and travel are the primary drivers of biological invasion both into and within the United States and prevention measures have been identified as the most cost-effective means of minimizing the introduction and thus impact of invasive species.

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.

Invasive species are one of the most serious threats to biodiversity. Up-to-date and accurate information on the distribution of invasive species is an important biosecurity risk analysis tool. Several databases are available to determine the distributions of invasive species and native species. However, keeping this information current is a real challenge. Ants are among the most widespread invasive species. Five species of ants are listed in the IUCN list of damaging invasive species, and many other species are also invasive in the Pacific.

St. Helena Island, 122 km2 (47 sq. miles) is a UK Overseas Territory in the South Atlantic. It is a remote volcanic island situated in the sub-tropics 1,127 km (700 miles) from Ascension Island and 2,736 km (1,700 miles) from South Africa. Its resident population of ca. 4,500 is serviced by a single supply ship which visits up to 25 times a year. Isolation has acted historically as a natural barrier to pest arrival and border control has followed the conventional practice of protecting agricultural interests through restrictions on fresh produce, plant materials, livestock and pets.

Pohnpei and their outer islands are very vulnerable to the introduction of Coconut Rhinoceros Beetle (CRB) because the CRB is present in Guam, Palau, Hawaii and South Pacific. Pohnpei is located near Guam, Palau and Hawaii and there is regular traffic by air and sea. For this reason it is very important that Pohnpei has a good Emergency Response Plan (ERP) in place not only for control/eradication but also for prevention and spread to other islands.