The Japanese weasel (Mustela itatsi) was introduced to the Ryukyu Islands, and has had a negative impact on native terrestrial vertebrates. Researchers evaluated the population status of three species of lizards living on Shimoji Island and Irabu Island. These three endangered lizards are the Kishinoue's giant skink (Plestiodon kishinouyei), the Miyako grass lizard (Takydromus toyamai), and the littoral whiptail-skink (Emoia atrocostata). Route censuses for the three species took place in 2022 from July 30th to August 4th and October 8th to October 13th at various locations on both islands. We recorded the Kishinoue’s giant skink in only 4 of 101 survey routes, the Miyako grass lizard in only 6 of 76 survey routes, and the littoral whiptail-skink in only 2 of 39 survey routes.

The Kishinoue’s giant lizard and the littoral whiptail-skink show a very limited distribution with the former found only in the northwestern part of Shimoji Island, and the latter found only in the southwestern part. Neither species was found on Irabu Island. The Miyako grass lizards were confirmed on both Shimoji Island and Irabu Island, however less frequently on Irabu Island suggesting a possible decline in population on Irabu Island. This study provides basic data on the population status of these three species of lizard.

This data will be an important resource for evaluating the recovery of lizard populations after a project to eradicate the invasive Japanese weasel has taken place.

Author

Hitomi Asato, Takahide Sasai, Takumi Yamamoto, Mamoru Toda

Title

Population status of three endangered lizards on Shimojijima Island and Irabujima Island, Ryukyu Archipelago, Japan

Journal

Current Herpetology

Link

https://doi.org/10.5358/hsj.43.159