A Tropical Triumph: Saving the Jamaican Iguana

The Jamaican Iguana has a dramatic boom-and-bust history. Described as abundant by renowned 17^th century Irish aristocrat-cum-naturalist Sir Hans Sloane, only 250 years later it would be all but gone. Endemic to Jamaica, it was declared extinct in 1948, having not been seen alive for eight years. The introduction of the small Indian mongoose was its downfall: brought onto the island to control rats and snakes, the mongoose soon established wild populations and predated the native fauna indiscriminately, including juvenile iguanas.

Then in 1990, half a century later, a hog hunter by the name of Edwin Duffus was walking through the Hellshire Hills of southern Jamaica when he noticed his dog chased and caught an unusual creature. Upon further investigation, it was none other than the Jamaican Iguana. It had been severely wounded and shortly died, but Edwin was able to take it to the aptly-named Hope Zoo in Kingston and tell the staff there were he had found it.

His discovery resulted in a flurry of activity. Efforts were launched to find further iguanas in the remote and rugged dry forest where the first one had been found. Six iguanas were discovered, along with evidence of nesting, leading researchers to estimate a remnant population of 50 individuals. Such a tiny population earned the species the precarious title of ‘rarest lizard in the world’ – but a better status than extinct, in any case.

Tactical Reintroduction

“When the existence of the Jamaican Iguana was reconfirmed in 1990, many folks in the scientific, conservation, and US zoo communities became interested in helping to recover the remnant population,” says Tandora Grant. She works at the San Diego Zoo Institute for Conservation Research and helps coordinate the Jamaican Iguana recovery program. In the early nineties, Tandora was studying populations of the related Cuban Iguana at the infamous Guantanamo Bay when she heard about the rediscovery of the Jamaican Iguana.

Tandora was interested in testing ‘headstarting’, a reintroduction tactic that involves raising individuals to maturity in captivity, before releasing them into their natural range. Given that the iguanas are most vulnerable when juvenile, this seemed a promising approach, and very applicable to Jamaican Iguanas. “The remnant population of iguanas was found to be all older adults,” says Tandora. “We suspected, and now know that almost all hatchling and juvenile iguanas are eaten by introduced non-native predators: mongoose, domestic cats and pigs.” The hypothesis was that the headstarting approach could circumvent this by only releasing the iguanas once they are large enough to be safe from predation. This strategy was hugely effective and has made the Jamaican Iguana an icon of reintroduction success among the conservation community. Hundreds of headstart releases have greatly bolstered the wild population, and the pace of progress is only gathering momentum.

Repairing the Ecosystem

But why are these iguanas so important? “Jamaican Iguanas play a very important role in the dry forest ecosystem in which they thrive,” explains Dr Stesha Pasachnik, Co-Chair of the IUCN Iguana Specialist Group. “The iguanas promote forest health by dispersing seeds and encouraging germination of native plants.” Not only that, their distinctive appearance makes them easily recognisable, and so elevates their status as a flagship species – an animal that can be used to figurehead conservation fundraising, to protect the iguanas and by extension the other species that share their habitat.

Along with a committed international team, a range of pioneering techniques is paving the way to success: radio tracking iguanas (and their predators) is helping the program to better understand animals’ movements and has the potential to identify further nesting sites, so protection efforts can be better focused. Edwin Duffus himself would also change professions following his discovery, from hunter to official iguana guardian. His input has been integral to assisting with the captive breeding programme and reintroduction efforts and guiding conservationists through the Hellshire Hills.

Looking to the Future

The Goat Islands, just offshore from the Hellshire Hills, are a promising place to establish a viable population. Although they are currently inhabited by mongoose, cats and rats, getting rid of these invasive predators would be a much simpler task on these small coral islands than on the mainland – and could benefit a whole entourage of at-risk species. “Once these non-natives are eradicated, iguanas, Jamaican Coney, Jamaican Boa, and Blue-Tailed Galliwasp can be reintroduced,” says Tandora. “Many species of endemic and migrating birds will also benefit from the restoration of the Goat Islands. It is the Recovery Group’s intent to create a ranger station and visitor centre experience as part of this restoration.” The resultant iguana population could also act as a ‘wild headstart program’, that could be used to supplement the Hellshire population.

Changing the hearts and minds of the nation is crucial for successful reintroduction efforts. Historically, iguanas have been feared and loathed by Jamaicans, but now that iguanas are so rare, lack of awareness is more of a barrier. “When I’m out showcasing the endemic and endangered species of our country, it surprises me that not many Jamaicans know about these animals,” says Jodi-Ann Blissett, who helps lead captive breeding and outreach efforts at Hope Zoo. “I think the more people know about these animals, the more they will try to protect them.” Much of the accelerating rate of progress in reintroduction efforts is due to more and more enthusiastic people getting involved.  “We have a lot of work still to do, but these iguanas bring people together just as they hold the forest together,” says Stesha. “Things have come a long way since the rediscovery, and I am excited to see what the future holds.”

Contributing Organisations

The rediscovery and reintroduction of the Jamaican Iguana involved a number of organisations. Some of them are listed below:

• San Diego Zoo Institute for Conservation Research, California
• Fort Worth Zoo, Texas
• Hope Zoo, Kingston
• International Iguana Foundation
• Jamaican Iguana Recovery Group (formerly Jamaican Iguana Research and Conservation Group)
• United Nations Development Programme
• Jamaica Environment Trust
• National Environment and Planning Agency, Jamaica
• Urban Development Corporation, Jamaica

References

• Richardson, J. 2018. The Jamaican iguana, an international success story in conservation. Loop Jamaica.
• Grant TD & Wilson BS. 2013. Cyclura collei. IUCN SSC Iguana Specialist Group
• Wilson, B., & Grant, T. D. (2016). The Jamaican iguana (cyclura collei): A report on 25 years of conservation effort. Herpetological Conservation and Biology,11(6), 237-254.