The purpose of this Position Statement is to highlight the pest status that non-native iguanas can attain when introduced to tropical and sub-tropical regions outside their native range, and to emphasize the devastating environmental and economic impacts they can cause.

Common Green Iguanas (Iguana iguana) and, more recently, Spiny-tailed Iguanas (Ctenosaura similis and C. pectinata) (Fig. 1) have been moved around the world, primarily for the pet trade. The intentional and unintentional release of iguanas has led to the establishment of uncontrolled invasive populations in more than 19 countries, with subtropical and tropical islands being most vulnerable (Table 1). To date, no country has been able to eradicate these species once a breeding population has become established.

Invasive iguanas can exhibit explosive population growth and reach staggering densities. On the small island of Grand Cayman, Green Iguanas have increased from a few individuals to hundreds- of-thousands within a decade. Invasive iguanas are causing multimillion-dollar impacts on infrastructure, agriculture, tourism, long-term food security, and biodiversity. For example, invasive Green Iguanas are a known airport safety hazard in Florida, Puerto Rico, and The Bahamas. They are also known to short-circuit power lines in cities, and their burrows have caused road collapses and coastal erosion (Fig. 2). Invasive iguanas can cause severe agricultural damage and defoliate native and ornamental plants (Fig. 3). Spiny-tailed Iguanas are a proven nuisance in Gasparilla Island, Florida, defoliating native plants and causing thousands of dollars in damages to homes and landscaping. In places where native and non-native iguanas co-occur, the survival of the natives is threatened through competition for food and space. In addition, hybridization with Green Iguanas is now the main threat to the survival of Lesser Antillean Iguanas (Iguana delicatissima) (Fig. 4).

We thus make the following tiered recommendations, which apply to all countries with tropical or sub-tropical regions, and especially islands:

For countries where non-native iguanas are not present: Develop and enforce country-specific regulations to ban importation and prevent the accidental introduction of non-native iguanas.

For countries where non-native iguanas are present in captivity, but have not been detected in the wild: Implement education programs focused on responsible pet ownership, encourage pet sterilization, ban the release of iguanas into the wild, and provide a sanctioned repository for unwanted captive iguanas.

For countries where non-native iguanas have been recently detected in the wild, but have yet to establish breeding populations: Immediately implement well-coordinated and resourced action plans to humanely remove all non-native iguanas before eradication becomes unfeasible (see AVMA guidelines: https://www.avma.org/KB/Policies/Pages/Euthanasia-Guidelines.aspx)

For countries with established breeding populations of non-native invasive iguanas in the wild:

Humanely eradicate existing populations where possible; if eradication is unsuccessful, implement continual management actions to control population growth and prevent further expansion. 

While translating the Dutch version of "de Amfibieen en Reptielen van Aruba, Curaçao en Bonaire" into English, I was forced to go through the entire text one more time, line by line. Thus it was inevitable that I ended up editing the text somewhat and adding to it as well. Since an English manuscript was now available, several people who had not been consulted previously could now give their comments, which have been incorporated in the English version. Thus the English translation is not a literal transcription of the Dutch version, although the differences between both versions are relatively minor. The islands of Aruba, Curaçao and Bonaire form part of a larger archipelago of islands along the Venezuelan coast. This archipelago includes all the islands from Los Monjes in the West to La Blanquilla in the East. The herpetofauna of the islands of Aruba, Curaçao and Bonaire should be viewed from this somewhat larger perspective. For this reason there are many references to the Venezuelan islands. Faunistic zones often transcend national borders. In this respect I have followed wagenaar hummelinck who in 1940 published the first general treatise of the herperofauna of this archipelago. My field guide is in large part based on this early work of wagenaar hummelinck (†).

This field guide is certainly not intended as a taxonomic work. Most guide books use slightly different classifications, sometimes all these differences can be quite exasperating. The latest classification is not necessarily the best, and some of the newer ideas have not gained general acceptance. In this English version the sub-species Leptodeira annulata bakeri and Crotalus durissus unicolor from the Dutch edition have been upgraded to full species status, in accordance with the prevailing taxonomic trends. I have simply tried to follow what seemed "the roads most traveled" and in many cases have indicated that other classifications also exist. In doing this I have certainly developed my own preferences, often siding with the "lumpers'', sometimes with the "splitters". I fully realize however that I do not have the expertise to make these kinds of taxonomic judgments, which are better left to others. It is however important to convey to the general public the idea that taxonomy has a subjective element and that taxonomy is not a static structure, but something that can change on the basis of new evidence or new interpretations. The field guide is also intended as a review summarizing available information on the herpetofauna of these islands. Local information on customs, beliefs and origins of local names has been included. The list of literature, cites many general works but is also intended to serve as a bibliography of the herpetofauna of the islands of Aruba, Curaçao and Bonaire. The sea turtles have not been included. In 1995 I published "De Schildpadden van Curaçao en Bonaire" (The turtles of Curaçao and Bonaire). This book was primarily intended for local use, one of its primary aims was to generate support for sea turtle protection. Since many books on sea turtles in the region already exist, there is no special need to translate this book into English.

Author's note, November 2017: This guide is somewhat outdated; some scientific names have changed, new invasive species have established themselves, at least on Curaçao, and of course new literature has appeared. Actually, a new edition is needed.

Curaçao and Bonaire form part of the Netherlands Antilles, while Aruba has a “status aparte” within the Kingdom of the Netherlands. All three islands are relatively arid compared to a typical Caribbean island, with mean annual rainfall of 409-553 mm, and experience several periods of drought lasting two or more years each century. A short history of the islands is given, and protected areas are described. The laws and regulations protecting amphibians and reptiles are complex, with general laws originating from the Kingdom of the Netherlands participation in international conventions (such as CITES) together with supplemental laws of the Netherlands Antilles and individual islands. Sea turtles are generally well protected, although their nesting beaches would be vulnerable to a rise in sea level. Among the terrestrial herpetofauna, only the Aruba Island rattlesnake (Crotalus unicolor) is on the IUCN Red List, being Critically Endangered. The status of this species and others of particular interest is described. The Curaçao Island snake (Liophis triscalis) should probably be included as Vulnerable or even Endangered, though there is insufficient information at present. Iguana iguana populations on the different islands, and the Curaçao whiptail (Cnemidophorus murinus murinus) on Klein Curaçao, are distinctive and significant for conservation. An overview is given of introduced amphibians and reptiles and their possible effects on the native fauna. The arid climate of the islands may hinder the establishment of invasive species, which are often not able to survive in the bush and thus reduces their impact on native species.