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Invasive Species

Most protected areas in the world are affected to some degree by invasive species.  The spread of plants and animals across the world has been occurring since humans began travelling across the oceans and the continents bringing with them species they like and unknowingly transporting other species.  Modern globalisation has made the spread of species easier.  Controlling/eradicating invasive species is a continuous aspect of protected area management, a line item in the budget.  Although the challenge of invasive species can be daunting, there are success stories on Pacific Islands.  Recovery: The Miracle on Palmyra atoll tells the story of rodent eradication by the application of the rodenticide, brodifacoum, and the subsequent recovery of plants and animals.

What are invasive species?

Invasive species are introduced species that become destructive to the environment or human interests on Pacific Island terrestrial and marine protected areas.  Invasive species can also include some native species that proliferate and become destructive following environmental changes caused by human activities.  Native species are plants, animals and other organisms that occur naturally on an island or offshore in a marine environment, having either evolved there or arrived there without human intervention. 

What's so harmful about invasive species?

Environmental harm by invasive species refers to a biologically substantial decrease in environmental quality as indicated by a variety of potential factors, including declines in native species populations or communities, degraded habitat quality or long-term habitat loss, and/or altered ecological processes. Environmental harm may be a result of direct effects of pests on native species, including preying and feeding on them; causing or vectoring diseases; preventing them from reproducing; outcompeting them for food, nutrients, light, nest sites, or other vital resources; or hybridizing with them so frequently that within a few generations, few if any truly native individuals remain.  Environmental harm also can be the result of an indirect effect of pest species. For example, decreased water bird use of a wetland may result from pest plant infestations reducing the availability and/or abundance of native wetland plants that provide forage or nesting for water birds.

Guidelines for Invasive Species in the Pacific (Directives relatives à la gestion des espèces envahissantes dans le Pacifique)

This document lists the essential components of a comprehensive and effective invasive species management programme. It has been compiled in consultation with Pacific island countries and territories, to support them in developing their invasive species work, and to guide regional and international agencies in providing assistance to them.

In general, invasive species control involves using methods based upon effectiveness, cost, and minimal ecological disruption, which considers minimum potential effects to non-target species and the protected area environment. Pesticides may be used where physical, cultural, and biological methods or combinations thereof are impractical or incapable of providing adequate control, eradication, or containment. If a pesticide will be needed, the most specific (selective) chemical available for the target species should be used unless considerations of persistence or other environmental and/or biotic hazards will preclude it. Pesticide usage may be further restricted in order to comply with any nation’s or territory’s environmental laws.  

Throughout the life of a protected area’s management plan, most proposed pesticide uses should be evaluated for potential effects to biological resources and environmental quality. Pesticide uses with appropriate and practical best management practices for habitat management as well as facilities maintenance should be approved for use where there likely will be only minor, temporary, and localized effects to species and environmental quality based upon non- exceedance of threshold values in chemical profiles. However, pesticides may be used in a protected area where substantial effects to species and the environment are possible (exceed threshold values) in order to protect human health and safety (e.g., mosquito-borne disease).

Major invasive species initiatives are underway in the Pacific.  Pay attention to information in the following networks and projects.  These web sites will be greatly expanded in the near future.

Pacific Invasives Battler Resource Base - This resource is to assist Pacific island invasive species practitioners in their battle against invasive species.  t includes the “Guidelines for Invasive Species Management in the Pacific” which outlines a set of themes and objectives to assist in forming a comprehensive invasive species programme. It includes the Pacific Invasive Species Battler Series on common Pacific topical issues and an option to see what new resources have been added lately. You can also search for documents, case-studies, reports and other media by selecting the appropriate “Guidelines” theme or objective, or use the general search function by selecting tags related to the resources.

Pacific Invasives Learning Network (for invasive species teams, information and much more)

Pacific Invasives Partnership

GEF-PAS Invasive Alien Species Project


Ants: AntWiki

AntWiki: a wealth of information on the world's ants

ANTS - Pacific Invasive Ant Key

Pacific Invasive Ant Key (PIAkey) - an illustrated identification guide to invasive ant species commonly encountered in the Pacific island region.

Asia-Pacific Forest Invasive Species Network

Battling Invasive Species in the Pacific : outcomes of the regional GEF-PAS IAS project

The GEF-PAS funded project "Prevention, control and management of invasive alien species in the Pacific islands' was implemented from late 2011 until September 2016.  The project which involved the nine participating countries of Cook Islands, Federated States of Micronesia, Kiribati, Nue, Palau, Marshall Islands, Samoa, Tonga and Vanuatu, was designed to assist in implementing the regional framework "Guidelines for Managing Invasive Species in the Pacific.

Campaign to Battle Invasive Species in the Pacific

Campaign to Battle Invasive Species in the Pacific

The largest cause of extinction of single country endemic species in the Pacific is the impact of invasive species. Invasives also severely impact our economies, ability to trade, sustainable development, health, ecosystem services, and the resilience of our ecosystems to respond to natural disasters. 

Crown of Thorns: Lime Juice and Vinegar Injections as a Cheap and Natural Alternative to Control COTS Outbreaks

Crown of Thorns Starfish Control

Crown-of Thorns-Starfish Life Cycle

Economics of Invasive Species Management

Economics of Invasive Species Management By Dr. Larry Clark, NWRC Director, USDA Wildlife Services

Posted on February 18, 2016



A project designed to reduce the environmental, economic, and human health impacts of invasive alien species in both terrestrial and marine habitats in the Pacific region. 

Global Biodiversity Outlook 4: A mid-term assessment of progress towards the implementation of the Strategic Plan for Biodiversity 2011-2020

Global Invasive Species Database (GISD)

The Global Invasive Species Database is a free, online searchable source of information about alien and invasive species that negatively impact biodiversity. The GISD aims to increase public awareness about invasive species and to facilitate effective prevention and management activities by disseminating specialist’s knowledge and experience to a broad global audience. It focuses on invasive alien species that threaten native biodiversity and natural areas and covers all taxonomic groups from micro-organisms to animals and plants.The Global Invasive Species Database (GISD) is managed by the Invasive Species Specialist Group (ISSG) of the IUCN Species Survival Commission.

Global threats from invasive alien species in the twenty-first century and national response capacities

Guidelines for Invasive Species Management in the Pacific

Tye, A. (compiler).  2009.  Guidelines for invasive species management in the Pacific:  a Pacific strategy for managing pests, weeds and other invasive species.  SPREP, Apia, Samoa.  

This document lists the essential components of a comprehensive and effective invasive species manage- ment programme. It has been compiled in consultation with Pacific island countries and territories, to support them in developing their invasive species work, and to guide regional and international agencies in providing assistance to them.

IBIS (Island Biodiversity and Invasive Species)

Impact of anthropogenic disturbances on a diverse riverine fish assemblage in Fiji predicted by functional traits

Anthropogenic disturbances particularly affect biodiversity in sensitive freshwater ecosystems by causing species loss. Thus, measuring the response of species to multiple disturbances is a key issue for conservation and environmental management. 2. As it is not practical to assess the response of every species in a community, we compared the performance of trait and taxonomic-based groupings of species for their abilities to predict species loss in a threatened freshwater fish assemblage. Specifically, we examined responses of a Fijian freshwater fish assemblage to deforestation, placement of anthropogenic barriers (overhanging culverts) and the presence of introduced cichlids. 3. Species grouped by traits showed more consistent responses to disturbances than taxonomic groups.

Invasive alien species in aquatic environments. Practical information and management insights

A new 2015 publication “ Invasive alien species in aquatic environments. Practical information and management insights” is now available in English. The first volume presents the current situation concerning IAS management in French freshwater (scientific knowledge, legislation, stakeholders, management).

The second volume is a collection of management experiments carried out in France and Europe. More than 60 managers have contributed and 26 species and 52 management experiments are described (objectives, protocols, results, costs, etc.). 


Invasive Alien Species - Pacific

Invasive Alien Species - Pacific is Birdlife International's major thrust to save Pacific island birds.  

Invasive Species Are Not Always Invading

Invasive Species Are Not Always Invading

This article in the New York Times referencing scholarly works discusses that not all invasives are bad, but underscores that is not necessarily the case in island ecosystems, so many of which are imperiled by invasives.

Invasive Species in the Pacific: a technical review and draft regional strategy

Invasive Species Research in the Pacific by the U.S. Geological Survey

Invasive Species Schools Resource Kit Factsheet 02

Invasive Species Specialist Group

Little Fire Ants in French Polynesia: synthesis report

Managing the Impacts of the Little Fire Ant (Wasmannia auropunctata) in French Polynesia

National Invasive Species Council

The National Invasive Species Council (NISC) was established by Executive Order (EO) 13112 to ensure that Federal programs and activities to prevent and control invasive species are coordinated, effective and efficient.

National Invasive Species Strategic Action Plan - PALAU

National Invasive Species Strategy and Action Plan - VANUATU

Pacific Invasives Initiative

Pacific Invasives Initiative is a leading provider of technical support and capacity development for invasive species management in the Pacific

Pacific Invasives Learning Network

Pacific Invasives Learning Network  empowers effective invasive species management through a participant-driven network that meets priority needs, rapidly shares skills and resources, provides links to technical expertise, increases information exchange, and accelerates on-the-ground action.  PILN serves teams of Pacific Island agencies responsible for invasives management, including agencies responsible for agriculture and natural resource management, international trade and border control, as well as environment and conservation.

Pacific Invasives Partnership

Pacific Invasives Partnership is the umbrella regional coordinating body for agencies working on invasive species (pests, weeds and diseases introduced from other places) in more than one country of the Pacific. 

Pacific Invasive Species Battler Series

Battle Invasive Species that Threaten Marine Managed Areas

Marine invasive species—including marine algae, fish, invertebrates, and pathogens—are widely recognised as a major cause of marine biodiversity loss worldwide (Molnar et al. 2008). Marine invasive species are spread throughout the Pacific along a number of pathways, including commercial cargo, fishing and cruise ships, recreational boats and gear, and marine debris. 

The Battler Series includes many other titles related to invasive species

Pacific Islands Ecosystems at Risk

Pacific Islands Ecosystems at Risk


Here you will find listings and descriptions of plant species that threaten ecosytems of the Pacific islands.  Also listed are many other invasive and potentially invasive plant species present in and around the Pacific region.


Pig Management Plan - Niue

The Wildlife Society Position Statement on Invasive Plants and Animals

The Wildlife Society Position Statement on Invasive Plants and Animals

An invasive species is defined by the multi-agency National Invasive Species Council1 as one that is “1) non-native (or alien) to the ecosystem under consideration and 2) whose introduction causes or is likely to cause economic or environmental harm or harm to human health.” This position statement uses invasive species as an umbrella term referring to alien, exotic, nonindigenous, and non-native species.

U.S. Department of Agriculture

U.S. Department of Agriculture (USDA) provides links to resources in the Pacific Islands with an interest in the prevention, control, or eradication of invasive species.

U.S. Framework for Early Detection of Invasive Species and Rapid Response

Safeguarding America’s Lands and Waters from Invasive Species A National Framework for Early Detection and Rapid Response

On February 18, 2016, the U.S. Department of the Interior released an interdepartmental frameowrk for the early detection and rapid response (EDRR) of invasive species--a coordinated set of actions to find and eradicate potential invasive species before they spread and cause harm..  The bedrock of the report is that the earlier you see the invasive and the quicker you respond then better the chances of eliminating the invasive species.