Conserving Anguilla’s Lesser Antillean Iguanas by Establishing a Sanctuary Free from Invasive Alien Species
Blueprint
ASSESS
Lesser Antillean Iguanas, once widespread throughout the Lesser Antilles, are now restricted to 14 subpopulations with only eight of these being free of invasive Common Green Iguanas. This species was recently elevated to Critically Endangered (2018) on the IUCN Red List of Threatened Species, where full details of distribution and declines are documented.
In 1998, the Anguilla National Trust (ANT) and Fauna & Flora International (FFI) published the report: Conservation Assessment of the Lesser Antillean Iguana, Iguana delicatissima, on Anguilla. Surveys indicated that Anguilla’s native iguana population was declining and threatened with local extirpation. A recommended project to eradicate the Common Green Iguana was cancelled after a few weeks due to insufficient funding.
With renewed interest, increased national capacity, and international funding, in 2015 the ANT relaunched its Lesser Antillean Iguana conservation initiative, supported by local government departments, FFI, and Durrell Wildlife Conservation Trust. Population assessments of both iguana species were conducted, with only 19 Lesser Antillean Iguanas recorded.
PLAN
Based on the number of iguanas encountered within the search area, and an approximation of the remaining habitat available, it was estimated that the total Lesser Antillean Iguana population could be as high as 250. The low encounter rate and presence of both Common Green Iguanas and hybrid offspring observed within the same locations as Lesser Antillean Iguanas suggests this estimate was likely far too high. With similar threats emerging in many Lesser Antillean Iguana range states, representatives with an increased interest in a collaborative approach to species conservation from Anguilla, Dominica, Guadeloupe, St. Barthélemy, St. Eustatius, and St. Martin met in Anguilla for a Lesser Antillean Iguana Sub-Regional Action Planning Workshop from 5–9 March 2018. The process for developing the plan largely followed the IUCN SSC Guidelines for Species Conservation Planning (2017), which included the development of a problem analysis for each population before developing solution analyses and defining a goal and objectives. This highly participatory process was facilitated by reptile conservation specialists from FFI and Durrell. The plan acknowledged the value and importance of coordinated approaches to iguana conservation and threat mitigation, and established the framework for long-term cross-territory collaboration.
ACT
The main purpose of the conservation strategy and action plan was to assist Anguilla, St. Barthélemy, and St. Eustatius in ensuring the long-term survival of the Lesser Antillean Iguana. Recognising the difficulty of protecting the species on the Anguilla mainland while invasive Common Green Iguanas were still present, conservation actions focused first on establishing an iguana sanctuary on offshore, privately-owned Prickly Pear East. Approximately 8 km from the mainland, this 31-hectare forested islet likely once held a population of native iguanas. Confirmed free of invasive iguanas and with the landowners’ permission, 22 Lesser Antillean Iguanas were moved from the Anguilla mainland to Prickly Pear East between 2016 and 2021 (9 male, 13 female). All of the iguanas were first genetically screened to confirm their purebred status.
Concurrently with the translocation, invasive Brown Rats (Rattus norvegicus) were successfully eradicated from Prickly Pear East in 2018. The island is routinely monitored for any sign of (re)invasion by rats and Common Green Iguanas, which can swim between islands or spread as stowaways on boats.
Bolstering genetic diversity of the Prickly Pear East founder population was identified as a key priority within the sub-regional conservation action plan. With few individuals remaining on the Anguilla mainland, the Government of Dominica was approached to donate Lesser Antillean Iguanas to supplement the relatively small founder population. Dominica graciously obliged, and in February 2021 ANT staff travelled to Dominica to assist with capturing iguanas, aided in Common Green Iguana control efforts, and trained Dominican counterparts in iguana husbandry. Following the month-long exchange, 10 Dominican delicatissima were translocated to Prickly Pear East in March 2021.
Prior to these actions, a holding facility was constructed to allow for proper care after capture, DNA testing was conducted to confirm species, an integrated management plan for the Prickly Pear Marine Park and islets (East and West) was developed, and a comprehensive, multimedia education campaign was launched to raise awareness about Anguilla’s Lesser Antillean Iguanas.
Results
Following six years of intensive conservation action, a population of Lesser Antillean Iguanas has been successfully reintroduced on Prickly Pear East. With the additional iguanas from Dominica, the population’s genetic diversity is expected to increase. Through ongoing monitoring of the islet and radio-tracking the founder iguanas upon release, ANT recorded 11 second-generation young Lesser Antillean Iguanas in 2021 — evidence of successful breeding by the founder population.
Collaborative relationships first established by developing the sub-regional conservation action plan have also been strengthened. Colleagues from St. Barthélemy have assisted Anguilla with biodiversity assessments, while ANT staff have assisted with iguana population assessments on St. Barthélemy. Colleagues based in and conducting work on St. Eustatius have helped with the interpretation of iguana genetic test results, and a stronger relationship has been forged with the Government of Dominica, the island’s Forestry, Wildlife and Parks Division, and its conservation NGO, WildDominique.
Visual & Audio References
© Farah Mukhida
Collaborations
Major
Partners
Government of Anguilla
Fauna & Flora International
Durrell Wildlife Conservation Trust
Agence Territoriale de l’Environnement (St. Barthélemy)
St. Eustatius National Parks Foundation
Forestry, Wildlife and Parks Division, Government of Dominica
Additional
Contributors
Prickly Pear East landowners; WildDominique (Dominica); Ardops Environnement (Guadeloupe); Les Fruits de Mers (St Martin); University of Roehampton (UK); Wildlife Management International Ltd (New Zealand); Syngenta; IUCN SSC Iguana Specialist Group
Donors
UK Department of Food and Rural Affairs (Darwin Plus); European Commission (Voluntary Scheme for Biodiversity and Ecosystem Services in Territories of European Overseas); Disney Conservation Fund; Fauna & Flora International (Species Fund); Rufford Small Grant for Nature; International Iguana Foundation; Mohammed bin Zayed Species Conservation Fund
Content Updated as of 8/7/2021