Iguanas are considered an invasive species in Florida, representing a significant challenge to the state’s environment and infrastructure. An invasive species is defined as a non-native organism that causes or is likely to cause economic or environmental harm, or harm to human health. The two most prominent species causing issues are the Green Iguana (Iguana iguana) and the Black Spiny-tailed Iguana (Ctenosaura similis). These reptiles, originally from Central and South America, have successfully established breeding populations in Florida’s warm subtropical climate. Their presence is a direct result of human activity, leading to extensive management efforts due to their rapid population growth and destructive habits.
Defining the Non-Native Presence
Iguanas are classified as non-native reptiles in Florida, meaning they did not historically occur in the region. The primary way these species arrived was through the exotic pet trade, with many individuals escaping or being intentionally released by pet owners. This introduction of nonnative species is a major source of the state’s current reptile problem. The Green Iguana was first reported in Florida in the 1960s.
The two main species of concern, the Green Iguana and the Black Spiny-tailed Iguana, are now well-established. Green Iguanas are the largest and most widely recognized. While primarily concentrated in South and Central Florida, including the Florida Keys, their range is expanding northward. Florida’s mild winters and abundant vegetation provide an ideal environment for these prolific breeders to thrive.
Specific Damage Caused by Iguanas
The negative impacts of iguanas are categorized into both ecological and structural harm, which is the basis for their invasive classification. Ecologically, iguanas are primarily herbivores that damage native plant species. They consume a wide variety of vegetation, including flowers, fruits, and ornamental landscaping plants such as hibiscus and orchids. This feeding behavior can defoliate native flora and has been linked to the decline of species like the endangered Miami blue butterfly, which relies on the gray nickerbean plant that iguanas consume.
Iguanas also compete directly with native wildlife for resources and habitat. They displace indigenous species by occupying burrows and nesting sites, which affects vulnerable animals like the Florida burrowing owl and gopher tortoises. Furthermore, they have been documented opportunistically eating the eggs of native birds, disrupting local ecosystems.
Structurally, the burrowing habits of iguanas create significant damage to human infrastructure. Female iguanas dig extensive underground tunnel systems for nesting, which can be up to 80 feet long. These burrows undermine sidewalks, foundations, and seawalls, leading to erosion and the collapse of canal banks and levees. Beyond the physical destruction, the volume of their droppings creates a sanitation nuisance in residential areas, including pools, and poses a risk of transmitting Salmonella bacteria.
Control and Legal Status in Florida
The Florida Fish and Wildlife Conservation Commission (FWC) has determined that iguanas are a prohibited and invasive species due to the high risk they pose to the state’s environment and economy. Because of this classification, iguanas are not protected in Florida, except by anti-cruelty laws, and their removal is actively encouraged. The FWC permits property owners to remove or humanely dispatch iguanas on their own private land without a license or permit.
The law requires that any removal must be done humanely, and the use of poisons is strictly prohibited for all reptiles. Acceptable methods of control include live-trapping for later destruction, or direct methods of humane destruction. Once captured, iguanas cannot be relocated or released at other locations within Florida. If a captured iguana is not immediately destroyed, a permit is required to possess the animal, which prevents their re-entry into the pet trade.
Property owners who are unable to safely remove iguanas are advised to seek assistance from professional nuisance wildlife trappers. The FWC provides guidelines for deterring iguanas, such as modifying habitat by removing attractive plants or filling in burrows to prevent nesting.