2015 Anguilla Population Assessment

Establishing baseline population and distribution data to inform population recovery of Iguana delicatissima on Anguilla, British West Indies

Report submitted by Farah Mukhida, Anguilla National Trust

Iguana delicatissima
Lesser Antillean Iguana from St. Eustatius. Photo by Thijs van den Burg.

The Anguilla National Trust (ANT) received project funds from the International Iguana Foundation in June 2015. Prior to receiving these funds, we began our work in earnest in February 2015. This project projected three major outcomes:

  1. Increased understanding of current population levels and distributions of the Lesser Antillean Iguana (Iguana delicatissima) and the Common Green Iguana (Iguana iguana).
  2. Potential for the establishment of an Iguana delicatissima satellite population on Dog Island.
  3. Increased awareness of the value of Iguana delicatissima and Dog Island as a biodiversity haven.

Population Assessments.  We completed 312 household surveys to establish the general range of I. iguana and I. delicatissima between February and March 2015. We mapped this distribution based on survey results. To follow, we then conducted in-field population assessments of I. iguana and I. delicatissima in May and June 2015. Herpetologist Mr. Rob Williams trained five ANT staff and Dr. Louise Soanes (University of Roehampton) in iguana population assessment techniques including: visual identification, quadrat and transect survey methodologies, capture methods, measurements, and data collection.

71 hours were spent in the field and 15 I. delicatissima were captured, beaded, and tagged. While we initially planned to release individuals after tagging/beading, after consultation with Anguilla’s Department of Environment, it was agreed that any suspected I. delicatissima should be held until genetic testing has been completed. This would avoid needing to recapture the individual should results indicate that the individual is in fact pure I. delicatissima and not I. iguana x I. delicatissima hybrids. Genetic samples were taken of 16 suspected pure I. delicatissima (based on morphology) and 21 I. iguana. Genetic testing to confirm species is currently being completed by Dr. Keiran Pounder, a geneticist at the University of Liverpool (United Kingdom) and we are awaiting results. As individuals were not released after capture, tracking work has not been possible. Instead, we aim to trial the use of IGOTU loggers on I. iguana in November–December 2015.

With funding provided by the Department of Environment and with support from the Department of Agriculture, an enclosure large enough to hold 11 iguanas was constructed. Two other cages constructed by the Department of Agriculture were donated for use for this project. Currently, 13 suspected pure I. delicatissima are being held on the grounds of the Department of Agriculture. Mr. Williams, Mr. Dan Lay (Department of Herpetology Supervisor), and Mr. Matt Goetz (Herpetology Department Head, Durrell Wildlife Conservation Trust) provided (and continue to provide) training and assistance with animal husbandry. I. delicatissima that are currently being housed at the Department of Agriculture will be released onto Prickly Pear East offshore cay (see description below).

Common Green Iguana from Curaçao. Note the large cheek scale that the Lesser Antillean Iguana does not have, regardless of size for either iguana. Photo by Bruce Sellmeijer.
Iguana delicatissima
Lesser Antillean Iguana on Dominica. Photo by Tandora Grant.

Based on field surveys and encounter rates, we estimate the I. delicatissima population on the Anguilla mainland to be 242 individuals (0.84 per acre), although this estimate should be treated with caution as iguanas are unlikely to be using all available habitat uniformly. This density estimate, however, is comparable to the I. delicatissima population on neighboring St. Eustatius, where the density has been reported to be 0.53 iguanas/acre in its preferred habitats. In contrast, surveys of I. iguana found localized densities equating to 31.94 individuals/acre. Surveys also suggest (with results reported for the first time) that I. iguana are not only present within the range of I. delicatissima, but are also occurring alongside them within well-known I. delicatissima locations. The threat of hybridization between the two species is high. Individuals were captured with morphological features intermediate between the two species, suggesting hybridization may already be occurring.

Results of fieldwork conducted between May and June 2015 are compiled/presented within the report below. This report will also be adapted to make it suitable for submission to a scientific journal in November/December 2015

Williams, R., D. Carter, T. Fleming, G. Hughes, L. Soanes, F. Mukhida. 2015. Conservation Plan for Anguilla’s Lesser Antillean Iguana (I. delicatissima): Report on Initial Field Research of May–June 2015. Anguilla National Trust, British West Indies. Unpublished report.

Iguana delicatissima
Photo from Wikipedia.

Re-Introduction Feasibility Study.  In June 2015, ANT staff, Dr. Soanes, and Mr. Williams, assisted local botanist Mr. Oliver Hodge, in assessing the feasibility of a reintroduction of I. delicatissima onto three of Anguilla’s offshore cays: Dog Island, Prickly Pear East, and Prickly Pear West. The cays’ topography, vegetative cover, vegetation structure, and potential natural and anthropogenic threats were assessed. Results of the study indicate that both Dog Island and Prickly Pear East could support a population of the native iguana. The study found that there was a high level of support from the owners of the Prickly Pear cays for a reintroduction while the Dog Island landowner is not as enthusiastic. The ANT and project partners are therefore working towards a reintroduction onto Prickly Pear East.

The results of the study are compiled/presented within the report:

Mukhida, F., L.M. Soanes, and R. Williams. 2015. Conservation Plan for Anguilla’s Lesser Antillean Iguana (Iguana delicatissima) Feasibility and Operational Plan for the Translocation of Iguana delicatissima to Anguilla’s Offshore Cays. Anguilla National Trust, British West Indies.

Public Awareness. We conducted a multi-media public awareness campaign to raise the profile of Anguilla’s I. delicatissima population.

  • Two press releases (15 January 2015; 13 May 2015).
  • Two radio shows on the ANT’s weekly radio program: Protecting Anguilla’s Natural Environment, on KoolFM 103.3 (19 May 2015; 1 September 2015).
  • Regular posts and updates on the ANT Facebook page (facebook.com/axanationaltrust), Twitter account (@axatrust), and Instagram account (axatrust).
  • Training in iguana identification and survey methodologies within our ANT Environment. Research. Action. Program (an afterschool environmental program for high school students).
  • Summer camp (“Where The Wild Things Are” – a week-long summer camp for three- to seven-year-olds) field trip the Department of Agriculture grounds to learn about iguana husbandry.

Due to our public outreach, individuals now regularly contact the ANT to report sightings of iguanas, as well as to request removal of iguanas from their properties. The Cuisinart Resort, Golf Course, and Spa is currently working with us to control the I. iguana population on their golf course.

Future activities planned:

  • Tracking of iguana using IGOTU technology (November 2015).
  • Iguana Fest Day (end of November/beginning of December).
  • Project update radio program (mid-November 2015).
  • End of project press release and radio program (December 2015).