The march of the Common Green Iguana (Iguana iguana): early establishment in Singapore and Thailand is facilitated by the pet trade and recreational parks

Abstract

The popularity of the Common Green Iguana (Iguana iguana) as a pet has contributed to its global occurrence as an invasive alien species. Early detection and control of invasive alien I. iguana populations is necessary to prevent the need for large and financially demanding eradication actions. Here, we collated information from digital footage and interviews regarding sightings of free roaming I. iguana specimens in Singapore and Thailand, and present evidence of early-stage invasions and establishment. Using species distribution modeling, we find that large parts of Thailand and neighboring countries have suitable habitat, which could facilitate the expansion of these alien populations if left uncontrolled. Additionally, we report singular I. iguana sightings in Hong Kong and Peninsular Malaysia. We call for awareness of alien I. iguana in the Philippines due to the high number of pet iguanas and reported CITES importations as well as the availability of suitable habitat throughout the archipelago. Further, we identify I. iguana presence to be facilitated by the release of pet-traded specimens and uncontrolled exhibition practices in recreational parks. We provide recommendations for implementing monitoring and eradication efforts and strategy recommendations to halt future spread and release.