Current Status of the Introduced Common House Gecko, Hemidactylus frenatus (Squamata: Gekkonidae), on Amamioshima Island of the Ryukyu Archipelago, Japan

Abstract: I surveyed distribution and abundance of a recently established population of Hemidactylus frenatus on Amamioshima Island of the Ryukyu Archipelago, Japan. I also attempted to evaluate the risk of further range expansion of this species within the island. In the first record of H. frenatus from the island in 2000, its range was restricted to one building in the urban area of Naze. In my survey in 2012, however, the gecko was already widespread, being the most abundant gekkonid species in the area. Hemidactylus frenatus was also found in many sites of the island outside Naze, most of which were located in the eastern part of the island. Based on the species distribution model, this eastern biased range expansion seems to reflect the greater abundance of suitable habitats in the eastern part. Two of the three western sites of H. frenatus were isolated from its major, contiguous range in the central-eastern parts by areas with apparently unsuitable habitats and scattered favorable habitats occupied...