The Green Anole (Anolis carolinensis) is a lizard native to the Southeastern United States. It is famous for its bright, emerald-green coloration, which it can rapidly shift to a dull brown or olive shade depending on temperature, mood, or environment. Males are easily recognized by the pinkish-red dewlap, a flap of skin beneath the throat that they extend during courtship displays and territorial warnings. Often called the “American Chameleon” due to its color-changing ability, the Green Anole is not a true chameleon.
The Official Conservation Status
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species classifies Anolis carolinensis as a species of “Least Concern” (LC). This designation applies to species that are widespread and abundant, indicating the Green Anole does not currently face an elevated risk of global extinction. The species maintains a large population size across its extensive native range, contributing significantly to this stable classification.
This designation means the species’ overall survival is not in jeopardy, even if localized population declines occur. Green Anoles are considered habitat generalists and can persist in various environments, including suburban parks and gardens. Their robust numbers across a wide territory provide a buffer against localized stresses.
Primary Threats to Anole Populations
Despite the global “Least Concern” status, Green Anole populations face pressure in the southern portion of their range from an invasive competitor. The arrival of the Brown Anole (Anolis sagrei) from the Caribbean has created an intense interspecies dynamic. The Brown Anole outcompetes the native Green Anole through direct aggression and resource competition.
The Brown Anole is generally more robust and assertive, frequently dominating interactions and displacing the Green Anole from preferred lower perches. This ecological shift forces the native species higher into the tree canopy, changing its primary habitat from the trunk and ground to smaller, smoother branches above. Researchers have observed that this displacement has driven rapid evolutionary change, with Green Anoles evolving larger toe pads over 20 generations to better grip the thinner perches.
Habitat loss and fragmentation due to rapid urbanization pose a compounding threat. As natural forested areas are converted to developed land, available habitat shrinks, concentrating populations. This habitat reduction, combined with pressure from the invasive Brown Anole, results in noticeable declines in native Green Anole numbers in many urbanized areas, particularly in Florida and along the Gulf Coast.
Geographic Range and Population Resilience
The Green Anole’s broad native distribution is the main factor underpinning its overall population resilience. The species is found throughout the Southeastern United States, ranging from the Florida Keys north to southern Virginia and west through Texas and Oklahoma. This vast geographic territory means that localized population declines, such as those observed in areas heavily invaded by the Brown Anole, do not jeopardize the species’ survival across its entire range.
Populations in the northern and western parts of the range, where the invasive Brown Anole has not yet established itself, remain stable and abundant. The Green Anole has demonstrated a capacity for local adaptation, with northern populations showing genetic adaptations for faster development in cooler temperatures. This ability to adapt to a wide range of thermal habitats contributes to the species’ robustness and ability to persist across diverse climates.
Conservation Actions and Citizen Science
Since the Green Anole is not a federally protected species, conservation efforts focus on monitoring, research, and understanding the invasive species dynamic. Citizen science is an invaluable tool for tracking population shifts and gathering data across the species’ expansive range. Projects like iNaturalist allow the public to submit reptile sightings, providing researchers with massive datasets on the distribution and relative abundance of both Green and Brown Anoles.
Local monitoring programs, such as “Lizards on the Loose,” engage communities in conducting standardized visual surveys to track the displacement patterns of the native species. This collective data helps scientists test hypotheses about niche partitioning and observe the behavioral and evolutionary responses of the Green Anole to its competitor. Maintaining native habitat corridors through local land management is also important, ensuring the Green Anole has access to the high-canopy environments it now frequently occupies.