SHIFTING ECOLOGY >>> Green Iguanas: Uninvited Settlers 

 

Originally native to Central and South America, green iguanas (Iguana iguana) began appearing in Ishigaki and the surrounding Sakishima Islands in the mid-1990s—likely the result of escaped or abandoned exotic pets. Like peacocks and other introduced species, they are recent unwelcome guests on the island.

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Since around 1994, they have established themselves across Ishigaki, especially in coastal zones and areas with access to freshwater. Growing up to 1.7 meters long, with distinctive tails and throat dewlaps, they are often seen basking or slipping silently into water. Their presence may appear benign, but their ecological footprint is not.

Green iguanas feed heavily on native vegetation, cultivated gardens, and crops, disrupting local flora and agricultural practices. Their burrowing further destabilizes soil, leading to erosion and damage to infrastructure. These behaviors pose growing challenges to both biodiversity and land use.

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Recognizing the threat, the Ministry of the Environment has listed the species as high-risk within Iriomote-Ishigaki National Park. Efforts are now underway to monitor populations, support humane removal, and raise awareness—part of a broader commitment to protect island ecosystems from escalating biological disturbance.