How Invasive Iguanas Threaten Florida's Native Species

Florida's native ecosystems evolved without large herbivorous lizards. When green iguanas (Iguana iguana) and spiny-tailed iguanas (Ctenosaura similis) established breeding populations in the state, they introduced new competitive pressures that native species were not equipped to handle. Today, invasive iguanas are contributing to the decline of several vulnerable and endangered species across South Florida.

The Miami Blue Butterfly

The Miami blue butterfly (Cyclargus thomasi bethunebakeri) is one of the most endangered insects in the United States. Once found throughout coastal South Florida, its populations have collapsed — and iguanas are part of the reason.

• Habitat destruction: Iguanas consume the native nickerbean (Caesalpinia bonduc) plants that Miami blue larvae depend on for food and shelter.
• Range overlap: The butterfly's remaining habitat in the Florida Keys directly overlaps with established iguana populations.
• Compounding threats: Combined with habitat loss from development and hurricanes, iguana herbivory adds another pressure that this critically endangered species cannot absorb.

Burrowing Owls

Florida's burrowing owl (Athene cunicularia floridana) is a state-listed Threatened species that depends on open, sandy ground for nesting — the same habitat preferred by iguanas for burrowing.

• Burrow competition: Iguanas take over existing burrowing owl burrows and can physically displace nesting pairs. Owl burrows that take weeks to construct can be claimed by iguanas overnight.
• Nest disturbance: Iguana digging near active owl burrows causes collapse and abandonment of nests with eggs or chicks.
• Habitat degradation: Intensive iguana burrowing degrades the soil structure that owls need for stable nest chambers.

Gopher Tortoises

The gopher tortoise (Gopherus polyphemus) is a state-listed Threatened species and a keystone species — its burrows provide shelter for over 350 other species. Invasive iguanas threaten this critical ecological role.

• Food competition: Both species are herbivores that consume many of the same native plants, including prickly pear cactus and various grasses.
• Burrow invasion: Iguanas have been documented entering gopher tortoise burrows, potentially disrupting nesting and displacing the tortoises.
• Population pressure: In areas where both species coexist, iguana populations grow far faster (20-70 eggs per year vs. 5-9 for gopher tortoises), creating an accelerating competitive imbalance.

Native Plant Communities

Beyond direct wildlife impacts, iguanas alter entire plant communities that native species depend on:

• Native orchids: Florida's native orchid species, already under pressure from habitat loss, face additional grazing pressure from iguanas that consume flowers and stems.
• Pollinator plants: Native flowering plants that support butterflies, bees, and hummingbirds are consumed by iguanas, reducing food availability throughout the food web.
• Coastal vegetation: Mangrove seedlings and sea grape in coastal areas are browsed by iguanas, potentially affecting shoreline stability and nesting habitat for sea turtles.
• Seed dispersal disruption: By consuming fruits and seeds, iguanas can alter the natural seed dispersal patterns of native plants, changing the composition of plant communities over time.

How Iguana Removal Supports Conservation

When you remove iguanas from your property, you're not just protecting your landscaping and structures — you're directly contributing to the preservation of Florida's native ecosystems.

1. Reduces competition: Every iguana removed means less pressure on native species for food, shelter, and nesting sites.
2. Protects habitat: Preventing iguana herbivory allows native plant communities to recover, supporting the entire food web.
3. Slows population growth: Active removal programs prevent exponential population growth (iguanas have no natural predators in Florida).
4. Supports keystone species: Protecting gopher tortoise burrows benefits the 350+ species that depend on them for shelter.
5. Legal and encouraged: The FWC actively encourages humane iguana removal as part of Florida's invasive species management strategy.

For more information about Florida's invasive iguana species and their behavior, visit our comprehensive guide on iguanas in Florida. To understand the full scope of property damage, see our property damage guide.