133 Feral Populations of Amphibians and Reptiles in the Ryukyu Archipelago, Japan 1 2 1 3 Hidetoshi OTA , Mitsuhiko TODA , Gen MASUNAGA , Akira KIKUKAWA , 1,4 and Mamoru TODA 1Tropical Biosphere Research Center, University of the Ryukyus, e-mail:
[email protected] 2Japan Wildlife Research Center 3Kanagusuku Junior High School 4Present address: Department of Zoology, Graduate School of Science, Kyoto University Abstract The Ryukyu Archipelago is an assemblage of many continental islands and a few oceanic islands scattered between Kyushu of Japan, and Taiwan. Recent changes in geographic ranges were reviewed for feral amphibian and reptile populations in this archipelago, chiefly on the basis of data and informa- tion becoming available after 1995. Six species of amphibians (Rana catesbeiana, Fejervarya sp., Poly- pedates leucomystax, Microhyla ornata, Bufo gargarizans miyakonis, B. marinus) and 14 reptiles (Chinemys reevesii, Cuora flavomarginata, Mauremys mutica, Trachemys scripta elegans, Pelodiscus sinensis, Hemidactylus frenatus, Hemiphyllodactylus typus typus, Lepidodactylus lugubris, Anolis caro- linensis, Ramphotyphlops braminus, Elaphe quadrivirgata, E. taeniura, Protobothrops elegans, P. mucrosquamatus) are considered to have one or more feral populations in the Ryukyu Archipelago at present. Some biological aspects of these populations are also reviewed. Possible effects of such feral amphibians and reptiles upon the indigenous biota, including a number of endemic and endangered taxa, are briefly discussed. Key words: amphibians, artificial transportation, feral population, Japan, reptiles, Ryukyu Archipelago 1. Introduction east of the Amami Group (Kizaki, 1985). Of these, the Senkaku Group is situated on the eastern margin of The Ryukyu Archipelago is an assemblage of the current continental shelf and thus is considered to approximately 70 inhabited islands and some uninhab- have been connected to the continent during the Late ited islets located in the southwestern part of Japan.