From 2008 through 2010, Alberto L. López-Torres, Héctor J. Claudio-Hernández, Carlos A. Rodríguez-Gómez, Ana V. Longo, and Rafael L. Joglar embarked on a study of the green iguana in Puerto Rico. They published their findings in Biological Invasions (2011) in the article “Green Iguanas (Iguana iguana) in Puerto Rico: Is it time for management?” In this article, they conclude that it is indeed time to save Puerto Rico’s biodiversity, native flora, fauna and agriculture from the ravages of yet another member of the invasive species threatening the Caribbean.
They write: “Iguana iguana is native to Central and South America, and was introduced into Puerto Rico in the 1970s as a result of pet trade. In several localities of eastern and northeastern Puerto Rico, this species has become abundant (Joglar 2005), possibly due to increased habitat availability and the absence of natural predators. Iguana iguana adults are mostly herbivorous, but occasional predation on bird eggs, chicks, invertebrates, small mammals and carrion have been reported [. . .]. The invasive biology of this reptile has not been studied in Puerto Rico, where [. . .] we found evidence that I. iguana is threatening native biodiversity and impacting infrastructure, agriculture and human safety. Thus, a management program to control the species must soon be developed to prevent this invasive reptile from becoming more widespread and dominant in other localities around the island.”
After studying the iguana’s reproductive phenology, breeding, and feeding habits, among many other factors, they also confirmed previous studies indicating that the foraging habits of I. iguana have been identified as a source of mortality to black mangrove (Laguncularia racemosa) at the San Juan Bay Estuary; that I. iguana may be attracting non-native predators (dogs, cats, and mongooses) to wildlife refuges and other protected areas; and that the iguanas’ digging habits could destroy leatherback eggs, especially in the Northeastern Ecological Corridor (NEC), where there is an overlap in reproductive season and nesting sites between I. iguana and Dermochelys coriacea (leatherback turtles).
Among their many suggestions, they indicate that: since adult iguanas are easier to remove during the courtship period, males may be separated from females; females may be captured during this period and radio-tracked to find potential nesting sites; and artificial mounds may be created to collect and destroy eggs, thus controlling iguana populations. However, they say, “nesting areas must be carefully searched because destroying nests indiscriminately may risk native species that are also attracted to these sites.”
[Many thanks to Sirena Montalvo Katz for bringing this situation to our attention.]
For a non-academic article and photo of the green iguana, see http://www.dollarman.com/puertorico/greeniguana.html