Some of the Earth’s most spectacular limestone formations can be found in Malaysia. For example, the world’s largest natural underground chamber, Gua Nasib Bagus, can be found in the limestone karsts of Gunung Mulu National Park, Sarawak.

Recognised as ‘arks of bio-diversity’, karsts are home to many unique species of birds, bats, insects, snails, fish, mammals and plants. Animals inhabiting karsts provide important ecosystem services such as pollination and pest-control in the surrounding areas.

Unfortunately, many karsts in Malaysia are being quarried for cement and marble, with logging activities and land clearance around it also degrading these bio-diversity havens.

A team of biologists have come up with a scientific basis to identify limestone karsts for protection.

Using data from 43 karsts across Peninsular Malaysia and Sabah, the study discovered that larger karsts, particularly those more than one kilometre square, deserve greater protection as they contain higher numbers of endemic land snails, and potentially other endemic plants and animals.

Larger areas tend to have greater habitat diversity, which enables them so support a higher number of unique species.

The protection of karsts has been mainly ad hoc and they are usually spared from quarrying by virtue of being situated within state and national parks, or if they possess some form of aesthetic or cultural value.

In addition, groups of karsts that have been isolated from other groups by geographical barriers such as mountains and rivers potentially contain significantly distinct species compositions.

Taking Peninsular Malaysia, for example, results now suggest that we should aim to set aside larger karsts on both sides of the Titiwangsa mountain range for protection if we want to maximise the conservation of endemic species.

Protecting large karsts in Pahang, Kelantan and Terengganu is not enough. We have to ensure that the larger karsts in Selangor, Perak, Kedah and Perlis are protected as well.

Concerns were recently highlighted regarding the potential quarrying of Gunung Jebak Puyuh, a pristine karst located in Pahang. This study shows that the concerns over the quarrying of Jebak Puyuh are warranted because its area is more than one kilometre square.

Indeed, the study found seven species of snails restricted to that area, compared to just one species on a much smaller karst measuring 0.06 km2 located further south. It is not surprising that a large number of unique species of plants and animals have been and continue to be recorded from Jebak Puyuh.

Pressure to mine karsts for limestone is likely to increase. A previous study showed that Southeast Asia has the greatest annual average increases in limestone quarrying - 5.7 percent a year.

With these findings, we hope that state governments would reconsider issuing mining concessions for larger karsts as they tend to be more biologically important.

Mining companies should also look towards extracting abundant limestone deposits below ground instead of leveling Earth’s precious biodiversity arks.

The writer is Species Conservation Manager, Peninsular Malaysia Programme,WWF-Malaysia .