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 Type (Animal)
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What is the Database of Island Invasive Species Eradications?
Islands are the epicenter of the current global extinction crisis and invasive vertebrates are a key threat to native plants and animals on islands. Removing invasive vertebrates from islands is an important island restoration tool to protect and restore island ecosystems and prevent extinctions.

The Database of Island Invasive Species Eradications attempts to compile all historical and current invasive vertebrate eradication projects on islands. The vast majority of the dataset is focused on invasive mammals. Data gathered from each project includes island location and characteristics, details about the eradication including focal species, methods and outcome, plus links and or contact details for learning more about the project. Parameter descriptions are described here

Figure 1. Cumulative number of successful invasive mammal eradication projects by year since 1950. Data are restricted to whole island events, excludes reinvasions, and data quality scored as good or satisfactory only.

While we make every effort to maintain the data please note that errors or omissions may still occur. Please read our disclaimer and note we also attempt to score the data quality for each eradication event. Should you become aware of errors, omissions, or have additional information to contribute about eradication events, we encourage you to contact We aim to update the data on an annual basis.

The online Database of Island Invasive Species Eradications was built with the support of The David and Lucille Packard Foundation, the National Fish and Wildlife Foundation, and the Global Environment Facility.

How To Cite?
DIISE, 2015. The Database of Island Invasive Species Eradications, developed by Island Conservation, Coastal Conservation Action Laboratory UCSC, IUCN SSC Invasive Species Specialist Group, University of Auckland and Landcare Research New Zealand.
Species details
Data in the database focuses on invasive terrestrial vertebrate species eradications from islands. Fish eradications are not included. Each species has a unique ID code linked to a common name, scientific name, family, and nominate animal type (e.g., rodent, ungulate, dog, cat, reptile, etc.). Invasive species populations were classified as either feral, domestic, feral and domestic, semi-feral, semi-feral and domestic. We defined semi-feral animals as those that are unfenced but receive food and care (primarily ungulates). We also note the year of introduction to the island where available.

Location details
Each island is allocated a unique identification from the Global Islands Database (GID), produced by the World Conservation Monitoring Centre ( ). We also use the GID to determine island size and identify a centralized location (latitude and longitude). Locations and island sizes are verified using satellite imagery (e.g. Google Earth) and/or literature sources and are corrected where needed. For islands not in the GID we allocated our own ID number and determined location and area in ESRI's ArcGIS. Country/territory are based on International Standards Organization 3166-1 alpha-2 codes ( ). Island names are standardized to be the common use within the larger country / territory and exclude common words for 'island' (e.g. islets, rocks, etc.). Human population sizes are based on ordinal categories of none, 1-10, 11-100, 101-1000, 1001-10000, >10000 or unknown and data sources represent available census data in government reports, websites and other sources.

Eradication details
Each eradication event in the database is an attempt to eradicate (i.e. completely remove) an invasive vertebrate population from an island. Where multiple invasive species are eradicated from an island these are considered separate eradication events, even if the same technique was used.

Since 2014 we assessed all eradication attempts for data quality based on definitions in Table 1. We expect any data summary or analysis to be restricted to only good or satisfactory data quality. We retain events of poor quality in the online database in the hope others can help us further qualify or remove these events. To update an eradication record, please contact us:

Eradication start and end date are reported for years only and represent years of operational activities on the ground where the eradication end date is the year that the eradication operations ceased. This typically coincided with the end of confirmation of eradication for hunting / trapping for ungulates and predators, or the end of toxicant application (or other methods) for rodent projects. Note that confirmation of eradications can occur some years after the end of operations, particularly for rodents which most often occurs two years after the eradication operation has ended.

We document the status of each eradication activity, based on definitions in Table 2. An eradication operation that successfully removed the invasive population is considered a successful eradication. Because reinvasions can follow a successful eradication, for the purposes of this online database, we added the option to view successful eradications within the context of a reinvasion status (See Table 2). We consider an eradication failure to be an operational failure, i.e. the project did not successfully remove the targeted invasive species from the island. This is different from a reinvasion event, which is only considered when the invasive species has re-established on the island, following a successful eradication. While reinvasions can be misdiagnosed as failures and vice versa, we erred on the side of caution and when it was unclear, defaulted to the operation as being failed. In these cases, data quality was considered poor. Note, the database also includes trial or research eradications that were used to inform larger operations.

Island eradication type (Table 3) refers to whether the operation required treatment of the entire island (whole island), or only part of the island (restricted range) to remove the invasive population from the island. Note, incursion responses are also included in the dataset, representing operations to remove a population prior to their establishment across the entire island.

Data on the primary and secondary method of the eradication are collected, including disease, hunting, trapping, toxicant, other, unknown, none (secondary method only). Where toxicant was used, the baiting method was noted as either aerial broadcast, bait station, hand broadcast, bait piles, unknown, other, or not applicable. The toxicant compound was identified where applicable.

References that cite part or all of these eradication events are provided, including a link if this is online.

References that cite part or all of these eradication events are provided. Contact details and organization of expert practitioners working on eradication projects are provided where they have been made available. Note some contact details have been withheld at the request of practitioners. Should you not see any contact details please contact and we are happy to share the knowledge we do have.

Table 1. Data Quality Definitions

Data Quality Definition
Good We can verify the attempt; we have a copy of the primary reference that details the effort
Satisfactory An expert practitioner has verified the event and/or we have limited information about an eradication, but what we do have came from a verifiable source (e.g. email from a reputable practitioner or cited in a review paper), and we can identify all of the following attributes: the island, end year (if applicable), invasive species type, eradication status, and primary eradication method.
Poor We cannot verify the attempt (conflicting information or unverifiable resource) and/or we lack evidence for at least one of the following parameters: island, end year (if applicable), invasive animal type, eradication status, or primary eradication method.
Unknown Data quality has not been assessed yet

Table 2. Eradication Status Definitions

Eradication Status Definition
Successful The operation to eradicate the invasive was successful and confirmed (i.e. the invasive species is no longer present on the island and to the best of our knowledge at the time of reporting, the invasive species has not reinvaded).
Successful (reinvaded) Operation was successful, but invasive subsequently reinvaded island
Failed The eradication operation was completed (there is an end date) yet it failed to remove the entire invasive population. Operational failure (as opposed to reinvasion). For rodent eradications, if there was uncertainty about why the invasive population remained (failure versus reinvasion), we assumed operational failure and classified data quality as poor.
To be confirmed Eradication operation is complete, but the operation has yet to be "confirmed" as successful or failed. This stage is typical for rodent eradication operations, with confirmation monitoring occurring 1 - 2 years after the eradication operation has ended.
In progress Eradication currently in progress at time of reporting.
Planned Eradication operation is being planned at time of reporting. Operation end year will likely be unknown.
Incomplete Eradication operation was started, but not followed through to completion.
Trial or research only Eradication operation was undertaken for trial or research purposes only with goal of gathering information, not to eradicate invasive species.
Unknown pre-status Eradication operation was undertaken but status of invasive was unclear beforehand. Typically undertaken for precautionary measures for rodent eradications.
Unknown Unknown outcome.

Table 3. Island Eradication Type Definitions

Island Eradication Type Definition
Whole island The whole island was treated to achieve eradication of the invasive species.
Restricted range The invasive only occurred on part of the island, and thus only part of the island was treated to achieve a whole island eradication.
Incursion response A response to an invasion in progress. Note: if an invasion results in a species recolonizing an island this requires a whole island eradication.
Unknown Eradication type unknown. Also use where the cause of the extirpation of the invasive species is unknown.

Version 2015.1: Major updates/revisions to data undertaken.
  1. The data are supplied only for conservation purposes, scientific analysis or research.
  2. The recipient of the data will provide a full and appropriate acknowledgement and citation in any materials or publications derived in part or in whole from the data; relevant citation details will be provided with each dataset. For any publications making substantial use of the data, the DIISE team welcomes the opportunity for co-authorship, collaboration and to comment prior to publication. Expressions of interest can be sent to
  3. Reproduction of the dataset or products derived from it, either whole or in part, for commercial purposes is prohibited without prior written permission from a member of the DIISE partnership. For the purposes of these Terms of Use, "commercial purposes" means a) any use by, on behalf of, or to inform or assist the activities of, a commercial entity (an entity that operates 'for profit') or b) use by any non-profit entity for the purposes of revenue generation. If you require permission please contact
  4. The recipient will not publish the data in their original format, either whole or in part, on a website, FTP site, CD, memory stick or any other media. The recipient should provide a link to the original data source location on the IUCN Invasive Species Specialist Group website where appropriate.
  5. Use of these data does not constitute endorsement by DIISE partners of any derived products, reports or analyses. Any logo from DIISE partners must not be used on any derived products, reports or analyses, or supporting materials, without express permission.
  6. Members of the DIISE partnership reserve the right to comment on the accuracy of representation of the data in material produced by a recipient.
  7. DIISE partners endeavor to maintain accurate and up-to-date data at all times, but can accept no responsibility for the consequences of errors or omissions in the data, for misuse of the data by any organization or individual, or for any damage done to computing systems into which the data are entered (see Disclaimer).
  8. Either an electronic or two paper copies of all products published using data supplied by the DIISE will be sent, free of charge, to the data authors via: Island Conservation, 100 Shaffer Road, Santa Cruz CA USA 95060 or via email to
People, organizations, and agencies that have helped develop the Database of Island Invasive Species Eradications
Island ConservationUniversity of California, Santa Cruz (UCSC)Coastal Conservation Action Lab, UCSC
Center for Integrated Spatial Research (CISR), UCSCThe University of Auckland, New ZealandLandcare Research (Manaaki Whenua), New Zealand
International Union for Conservation of Nature (IUCN)Species Survival Commission (SSC), IUCNInvasive Species Specialist Group, IUCN SSC
The DIISE partnership endeavors to maintain the most accurate and up-to-date data at all times. However, if errors or omissions are identified, the user should notify Island Conservation so that they can be corrected in future releases of the data. Please mark all correspondence: "Database of Islands and Invasive Species Eradications".
The DIISE team make no warranties or representations, express or implied, regarding the use of the material appearing in this dataset with regard to their correctness, reliability, accuracy, or otherwise. Please take note of data quality metrics and definitions. The material and geographic designations in this dataset do not imply the expressions of any opinion whatsoever on the part of the DIISE team concerning the legal status of any country, territory or area, nor concerning the delimitation of its frontiers or boundaries. Neither the DIISE team nor its affiliated or related entities or its content providers shall be responsible or liable to any person, firm or corporation for any loss, damage, injury, claim or liability of any kind or character based on or resulting from any information contained in the dataset. The DIISE team may update or make changes to the data provided at any time without notice; however, makes no commitment to update the information contained therein.