A network of citizens' groups opposing the construction of an airport on Ishigaki Island, Okinawa Prefecture, have acquired a plot of land where the airport is slated to be built, members of the network said Tuesday.

Toru Ikushima of the Association to Protect Shiraho Coral Reef said the groups obtained the 780-sq.-meter plot in a bid to halt construction that would ravage internationally significant coral reefs and threaten at least 115 rare and endemic species.

The plot lies roughly adjacent to where the runway or the apron of the new airport will go, Ikushima said during a news conference at the Environment Ministry press club.

The land is currently owned by 24 people, and the groups said they hope to get 1,000 people to register as land owners, asking them to pay 5,000 yen each to join the movement.

"The biggest threat to the environment (on Ishigaki Island) is the runoff of red soil that would damage the coral and ecosystem as a whole," Ikushima said, adding that the World Conservation Union has twice surveyed and twice called for preservation of the Shiraho coral reefs.

Construction of the airport is scheduled to begin in 2004 and finish around 2011.