National / Science & Health

Endangered bat, believed to be extinct locally, discovered in former U.S. training area in Okinawa

by Alex Martin

Staff Writer

A former U.S. military training site in Okinawa Prefecture provided a precious refuge for a critically endangered bat unseen on the prefecture’s main island for 22 years. The Yanbaru whiskered bat (Myotis yanbarensis) was captured by a research team two months ago, Kyoto University revealed Monday.

Jason Preble, a doctoral student at the university, first ensnared one of the tree-dwelling bats on the night of Feb. 20. The discovery took place during a survey of a large forested area in the northern part of the island that was returned to Japan by U.S. forces in December 2016.

Preble released the 4.9-gram male after fitting a tracker to it to follow its movements. He subsequently caught two more in the former U.S. military Northern Training Area using synthesized bat calls as an acoustic lure. All three bats were released back into the wild.

The Island Bat Research Group at Kyoto University, of which Preble is a part of, was one of the very first teams to be granted access to the site, which is part of Yanbaru, the subtropical forested area in northern Okinawa.

The tree-dwelling bat was first discovered in the area in 1996, when two specimens were collected. The species was later observed on a few occasions on Tokunoshima and Amami-Oshima islands but wasn’t seen again and was feared to be locally extinct. It has been declared critically endangered by both the Ministry of Environment and the International Union for the Conservation of Nature.

The presence of the bat in a zone that was off-limits for over half a century appears to indicate that the area may have served as a sanctuary for sensitive wildlife, according to assistant professor Christian Vincenot, who leads the research unit.

He said the discovery revives hopes regarding the conservation of the rare species, but also suggests that it may be range-restricted to a very small part of Yanbaru forest and may still be at risk of local extinction.

Vincenot urged extreme caution in the management of the area, which is currently a candidate for UNESCO World Heritage status.

Bats have been shown to be very sensitive to infrastructure development. A new airport runway opened in 2013 on Ishigaki Island was constructed overtop of bat caves, resulting in an alarming population decline.