What are invasive species? | Why focus on islands? |
Invasive species are introduced organisms that can cause harm to the environment, the economy, or human health. They are mostly spread through human activity and include insects, weeds, fungi, bacteria, viruses, fish, mammals, snails and other species. Many of these harmful organisms are already present in Pacific Island Countries and Territories (PICTs) where they are having detrimental impacts on several sectors including food production, tourism and trade as well as ecosystems and biodiversity. More invasive species are in countries neighbouring PICTs.
For further information on invasive species, please click on the following links;
- The International Union for the Conservation of NaturE - Invasive Species Specialist Group (IUCN-ISSG)
- Guidelines for Invasive Species Management in the Pacific
- Global Invasive Species Database
Why focus on islands?[back to top]
- Islands are important ecosystems
Many island ecosystems are unique. They contain landforms and biotic communities (including aquatic and marine systems) that are not found at continental (land-locked) sites. They also contain a disproportionately large percentage of endemic species (those that occur nowhere else). Islands also provide critical breeding habitats for mobile species such as seabirds and turtles.
- Islands are under threat
Island biotas are especially vulnerable to human-induced changes. More species have gone extinct on islands than in comparable continental sites. For example:
(i) 80-90% of all reptile extinctions
(ii) 80-93% of all bird extinctions
(iii) 50-81% of all mammal extinctions
have taken place on islands
Invasive species impacts are escalating rapidly as more new species become established in island ecosystems. There is a pressing need to more effectively manage the threats invaders pose to islands if further extinctions are to be averted and the livelihoods and lifestyles of island people are to be sustained. Active management - including preventing invasions in the first place, eradicating invasives where this is achievable, or controlling them where other approaches are not feasible is urgently required.
- Islands present important management opportunities
Islands present unique opportunities to effectively manage invasives. As they are isolated by water it is difficult for terrestrial invaders to colonise (or re-colonise) them. Also, because of their isolation and their relatively small size, eradicating some invasive species from islands is potentially more achievable than at continental sites. These attributes, coupled with their vulnerability, make islands important places to "take a stand" against invasives. Exciting recent advances have been made in managing a growing array of invasive species on islands, and important social and economic - as well as biodiversity conservation outcomes have been attributed to these successes.
The thrust of the Pacific Invasives Initiative is to build on these successes so that the tide of invasions may be turned back on many more islands around the world.