The Faculty of Natural Sciences, Department of Biology, University of Puerto Rico have published an article Called “March of the Green Iguana: Non-native Distribution and Predicted geographic Range of Iguana iguana in the Greater Caribbean Region”.

The Abstract from the article says:

Green Iguanas (Iguana iguana L. 1758) have been introduced outside their native range largely through the pet trade. In many places, exotic populations have invaded and many have become established.

Of special concern is the Greater Caribbean Basin, where several exotic populations of Green Iguanas have had a negative impact, and may threaten the conservation of several native species, including possible native and distinct forms of I. iguana in the Lesser Antilles, and the endangered Lesser Antilles Iguana (I. delicatissima Laurenti 1768).

We assessed the risk of spread and invasion by Green Iguanas in the Greater Caribbean Basin using the maximum entropy niche-modeling algorithm (MaxEnt) to predict the potential distribution of this reptile.

We used a total of 187 location points that represented occurrences from both the native and the invasive range, coupled with environmental data as predictor variables.

Our model had average training and test AUC values of 0.90 and 0.87 respectively, indicating a high predictive ability. The model predicts suitable conditions for I. iguana in south and central Florida (mainly along the coast), and in regions of all the islands in the Caribbean.

Given the known negative impact of Green Iguanas and their dispersal capabilities, governments in the Greater Caribbean Basin should manage non-native populations to prevent further spread, and revise and enact laws that allow management agencies to respond quickly in the case of new Green Iguana incursions.

The whole article can be downloaded here at www.ircf.org/journal/wp…/RA_19.3_150-160_Falcón-etal_print.pdf

Also read this article:

Feral Iguanas in Florida From Green Iguana Society

The Problem: The term “feral” is used to describe animals that used to belong to someone as pets or livestock, but now live on their own as wild animals. Feral iguanas are common in some parts of southern Florida. To be more precise, the wild green iguanas in Florida are a mix of former pets and the offspring of these animals. Green iguanas are generally thought not to be native to the United States. This places wild green iguanas in the category of “invasive” or “exotic” species — non-native species that have been introduced into a new habitat and which often cause damage to the ecosystem. Florida is overrun with invasive species, most of which come from the pet trade. Because of their tropical nature, pet green iguanas that have escaped or have been released by irresponsible owners have thrived in southern Florida, and their populations are growing rapidly in some areas as the iguanas breed successfully. Practices such as giving iguanas away as prizes at carnivals have exacerbated this problem. While some people find wild green iguanas to be a beautiful addition to the Florida ecosystem, the sad fact is that they do not belong there. As a consequence, at this time, they do not have a balanced place in the ecosystem with predators and competitors to keep their populations in check. At this time, very little has been done to study the ecological impact that green iguanas may have in Florida. However, given the negative impacts of many exotic species around the globe, such as the zebra mussel, English sparrow, walking catfish, and plants such as kudzu and purple loose-strife, it is best to assume that green iguanas will have some negative impact on the Florida ecosystem.

Not only may they have harmful ecological impacts, but iguanas are becoming a serious nuisance species in some areas. The Green Iguana Society gets many letters each month from frustrated Florida residents, asking how to remove or repel wild green iguanas from their yards and pools. According to the University of Florida Institute of Food and Agricultural Sciences (UFIFAS) , green iguanas in Florida eat shrubs, trees, landscape plants, orchids, and fruits such as figs, mangos, berries and tomatoes. Ornamental vegetation can be decimated by one large iguana taking up residence in a yard. In addition to destroying landscaping efforts, iguanas also cause problems by digging nesting burrows that can undermine sidewalks, sea wells and foundations. Iguana feces are odiferous, unsightly, and may harbor Salmonella bacteria. Because iguanas often prefer to defecate in or around water, it is not uncommon for an iguana to use a private pool as a defecation area. Large adults may be aggressive towards people and pets if they feel threatened.

Possible Solutions: Several non-lethal ways to repel iguanas from an area have been suggested. The Green Iguana Society would encourage people to try these methods first before moving on to something more drastic. To begin with, try making your yard less iguana-friendly. Do not feed the iguanas that come around. Even if you like them or don’t mind their presence, your neighbors may not feel the same way. Feeding them only encourages them to stay around, so don’t do it. The UFIFAS also suggests removing protective cover such as dense thickets and piles of landscape rocks or wood from your yard. Sheet metal around the base of trees may deter iguanas from climbing them and may encourage them to move on. Plants can be protected by screens or wire cages. Another method used to protect plants and deter iguanas (as well as other unwanted animals) from a yard is to spray plants with a mixture consisting of 3 cloves of garlic and 4 red-hot peppers mixed with a bucket of water. To protect your pool, cover it when it is not in use.

In addition, the Green Iguana Society wondered if placing bird-of-prey decoys around the yard would deter iguanas. Young iguanas fall prey to predatory birds, and even adult iguanas react visibly to a large bird (or plane) flying overhead. We thought that owl decoys, which are designed to deter smaller birds, may offer some protection. Bird-of-prey wind socks may work better yet. However, we have heard from several site visitors that this doesn’t work to deter iguanas.

Trapping iguanas is possible, but it is illegal to relocate iguanas because, as a non-native species, they cannot be released into the wild – even if they were caught in the wild to begin with. According to the Florida Fish and Wildlife Conservation Commission, Florida rules do not allow the release of any non-native species without a permit. Therefore, if captured, iguanas must be destroyed humanely. Obviously, the Green Iguana Society is uncomfortable with the idea of trapping and destroying green iguanas. It saddens us to realize that iguanas will be the ones who must pay the price for something they had no hand in – the irresponsibility of pet owners who couldn’t or didn’t keep their iguanas safely in captivity. However, we understand that iguanas can cause problems for people and in some cases must be removed. On private property, iguanas can be trapped at any time without a permit. Information about the types of traps and snares that can be used and how to use them properly is available at the UFIFAS web site. If you decide to trap iguanas on your property, please do so in a humane manner. Use appropriate traps and check them often. Turn the iguanas over to the appropriate authorities for humane euthanasia. Please do not attempt cruel methods of disposal. Be aware that iguanas are protected by anti-cruelty laws. Contact the local humane society or animal shelter for information on who to bring a captured animal to. Turning live animals over to pet stores or private citizens for pets may be possible, but feral iguanas, particularly older ones, are difficult to tame and make poor pets. Check out all the possibilities available to you first before you capture any animals.

Some individuals offer their services as iguana trappers for hire. These individuals have the appropriate connections to dispose of captured animals appropriately and humanely. They also know how to properly use various types of traps. If you have a problem iguana on your property, have tried the non-lethal methods of deterring it, and have decided that it must be removed but you don’t want to have to deal with it yourself, contacting an iguana trapper may be an option. One such service is provided by David Johnson, owner and author of IguanaTrapper.com. Please understand that The Green Iguana Society is not encouraging people to use lethal control methods on feral iguanas, nor are we vouching for the services of this or any other iguana trapping service. We are simply providing as much information as we can to help people who are struggling with a feral iguana problem. It is important to understand that when one iguana is removed from an area, another will move in to replace it. For this reason, trapping and removing iguanas is probably best reserved for particularly aggressive or destructive individuals and should not be seen as a permanent solution to the problem.

We have recently become aware of a product called Quack’s Iguana Repellent. This product claims to be an all-natural repellent that uses scents and bad tastes to keep iguanas out of yards. None of us here at the Green Iguana Society has yet tried this product, but we have heard from some of our Floridian site visitors that this does not work. One site visitor wrote in with his own recipe for repelling iguanas: spraying the plants each day with a combination of RealLemon and Oust(TM) lemon-scented spray. According to this visitor, this is expensive but worth it if you have a few plants you really want to protect. Again, nobody at the Green Iguana Society has tried this, but we thought we’d pass on ideas as they come in.

Here To Stay – It is important that everyone works together to help educate people about the dangers of releasing or allowing escape of pets into the wild. Urge iguana owners to spay or neuter their pets so that if they do get loose, they won’t contribute to the feral iguana population. Responsible pet ownership is the first step toward preventing problems such as feral iguanas. Speaking out against giving iguanas and other animals away as prizes to unprepared carnival and fair visitors can also help. If you see such a practice going on, contact the local sponser of the carnival.

Taking the steps above can help, but the fact of the matter is that green iguanas are now a permanent part of the south Florida ecosystem. In fact, there is some evidence that iguanas may actually be native to the Florida Keys. In the November 2009 issue of Reptiles magazine (Vol. 17, Number 11), noted reptile vet Douglas Mader stated the following: “I have done a lot of research on the origins of the iguanas in the Keys. There are accounts of wild green iguanas living here from the 1950s. That’s long before these animals were ever popular as pets and long before people could have released them back into the wild…my investigations so far point to the fact that green iguanas may have a native origin (in the Keys).” Regardless of their origin in the Keys or in the rest of their range in Florida, the population of green iguanas has grown so fast that eradicating them at this point is not an option. While we understand the frustration iguanas cause when they damage property and become a nuisance, we encourage people to try to find non-lethal ways of tolerating iguanas in their area. Learning how to co-exist with feral iguanas is something that citizens of southern Florida must do. If you know of other ways to deter iguanas from a yard and plants or pool, please let us know by sending us an email at anything(at)greenigsociety(dot)org.

For more on this story go to:

http://www.greenigsociety.org/feraligs.htm