"The four species which have become rare are otomops johstonoi from Flores and Alor, neoptenus trostii from Sulawesi, rouseptus linduenst from Lindu Lake in Sulawesi and otomops forrmosus from Java," bat expert from the Center of Biological Research of the Indonesian Institute of Sciences (LIPI), Ibnu Maryanto, said at a press conference on International Southeast Asian Bat Conference at Royal Hotel here on Monday.
Ibnu said the two bat species had been difficult to find since five to 10 years ago.
Among the factors that had reduced the bat population in the country were forest exploitation and mining in limestone areas which are the habitat of bats, he said.
Ibnu said bats play an important role in the eco-system balance and are useful for human life.
He said bats were one of mamals that can fly are a natural predator and pollinator of plants.
Of the 225 bat species in Indonesia, 75 are fruit eaters and pollinators while the remaining 148 are insect eaters that help man fight insects and diseases.
"In an hour a bat could eat 6,000 insects. So imagine if bats are gone we can predict a lot of diseases like malaria will happen," he said.
Ibnu said large colonies of bats in limestone caves are vulnerable to threats. "Changes caused by human beings could affect their livelihood," he said.
He said exploitation of limestone for industries that had destroyed a lot of caves in almost all karsts in Indonesia has been one of the causes for the extinction of certain bat species.
The chief of LIPI, Lukman Hakim, meanwhile said the impact of the loss of the bat`s role as pollinator has already been felt now.
"We used to find "Durian Parung" in Parung, Bogor, in the past but now the fruit is difficult to find there," he said.
Lukman said Indonesia has the world`s largest bat families (11 families) but it has also lost the largest species due to the destruction of their habitats.
The destroyed bat habitats could be found everywhere in the country such as Jakarta, Bogor, Depok and Bekasi as most of the forests and trees there had already gone.
Lukman said as a reserach institute LIPI cares about the environment and has strengthened its cooperation network with bat researchers conducting research activities in Southeast Asia.
"The bat conference activity must be increased in view of the benefit of bats for human life" he said.
He said the results of discussions at the conference would be used for recommendations to the government for the protection of bat habitats.
The bat conference of South, Southeast and East Asia that will last from June 6 to 9 is the second after the first held in Pucket, Thailand in 2007.
A total of 80 researchers from 20 countries namely Indonesia, Malaysia, the Philippines, Brunei Darussalam, Vietnam, Cambodia, Laos, Singapore, India, China, Japan, Taiwan, the US, Canada, Britain, Australia, Pakistan and Vanuatu attended the conference.