The bizarre creatures live deep within the karst landscape of Hon Chong in southwest Vietnam, a highly biodiverse area of limestone hills and caves that faces severe threat from quarrying by cement companies.
Limestone, a nonrenewable resource, is a key raw material for cement. Vietnam is the largest cement producer in South-East Asia, with 58 integrated cement plants producing 91.4 metric tonnes a year, while Indonesia is a far second, with 15 integrated plants and 63.1 metric tonnes of production capacity. 
“We believe nowhere else on earth is there such a high concentration of species that faces such intense risk.”
Tony Whitten, FFI
However, as Vietnam rides a construction boom into karst regions, environmental impact assessments have rarely taken into account the ecologically unique nature of limestone areas or the profound consequences of extracting limestone with respect to biodiversity. 
Destruction in Hon Chong
In Hon Chong, cement companies have already destroyed an estimated 42 per cent of Hon Chong’s limestone hills, according to Fauna & Flora International (FFI), a conservation organisation founded in 1903 which operates in 40 countries.
“Only 258 hectares remain of what was once a 447-hectare ‘archipelago’ comprising 17 habitat ‘islands’ housing an array of endemic species”, where many of the cave-dwellers have evolved without eyes because these are no longer needed. 
As a result, the remaining limestone peaks of Hon Chong now house “at least 31 threatened species, of which six are critically endangered”, reports the FFI, which played a key role in the establishment of major conservation bodies like the International Union for Conservation of Nature (IUCN) and the World Wildlife Fund for Nature (WWF).
“We believe nowhere else on earth is there such a high concentration of species that faces such intense risk — the scale of the likely extinctions if cement companies continue their activities unchecked is really quite shocking,” says Tony Whitten, FFI Asia-Pacific regional director and a former biodiversity specialist at the World Bank, referring to the findings of the IUCN’s Cave Invertebrate Specialist Group, which he co-chairs.
Whitten explains that the isolated nature and the extreme conditions often found within karst or limestone ecosystems have created the “perfect recipe” for high biodiversity. It is thus not unusual for a single hill or cave to be home to species not found anywhere else. Some cave species have become blind or wingless and cannot survive outside the cave or soil where they have evolved.
In the case of the Hon Chong ghost snail, from the endangered species of Macrochlamys, it is known only from two Hon Chong caves. About half of the snail’s original range has already been lost and the remainder faces potential threats from quarrying.
“Another snail species discovered a year ago on a single hill in the area is probably extinct now because the hill is being quarried,” notes Jaap Vermeulen, a biologist and geologist who led a team of scientists in 2014-2015 to survey plant and invertebrate biodiversity in 25 limestone hills at Hon Chong.
“Another snail species discovered a year ago on a single hill in the area is probably extinct now because the hill is being quarried.”
Vermeulen tells SciDev.Net that one remnant of a hill being quarried includes a sinkhole, an environment not present elsewhere in the area, with probably a rich biodiversity. Another hill harbours a substantial population of the Indochinese silvered langur, an endangered primate species.
More than 30 assessments of Hon Chong’s threatened endemic species have been posted online at the IUCN Red List of Threatened Species, which assesses the conservation status of species worldwide.
Calls for a nature reserve
The cement companies responsible for these threatened extinctions are mostly state-owned but one is a joint venture with Holcim Vietnam, a member of the LafargeHolcim group, one of the world’s largest cement suppliers.
The International Finance Corporation, the World Bank’s private sector arm, provided US$97 million financing to build Holcim Vietnam’s huge cement plant in Hon Chong, despite warnings in 1995 by Louis Deharveng, an entomologist with France’s National Museum of Natural History,that “no comparable ecosystem exists elsewhere in Vietnam”. 
Recent reports indicate Holcim Vietnam is considering pulling out of Vietnam because of cement oversupply in the domestic market. State-owned Vietnam Cement Industry Corporation, which holds 35 per cent stake in Holcim Vietnam, is set to buy it out. However, this arrangement may do little to change the business-as-usual situation at Hon Chong.
While Holcim Vietnam has cooperated with IUCN on some proposals for biodiversity management of its quarries, which include mapping the distribution of threatened plants and wildlife, FFI contends that “few effective actions have been taken to avoid species extinctions.” The local government is considering a nature reserve that would give protection to nine of the 34 hills but only a quarter of the Hon Chong species would benefit.
“To ensure the survival of a considerably larger fraction of the limestone biodiversity, six more hills should be included in the planned conservation area,” Vermeulen stresses. In addition, Whitten tells SciDev.Net, “I'd like all the cement companies there to reach out and explore the options in a consultative manner for avoidance and minimisation, as first steps in the mitigation hierarchy. If extinctions in the wild are unavoidable, the companies should be open about this. They should also ensure that people are given the chance to rescue the threatened species, and for plans to be put in place for captive populations to be maintained.”
He says, this sort of decisions can be made at the companies’ own expense, as has been done in other parts of Asia. He cites the case of cement firm Lafarge in Malaysia, which said it won’t quarry a cave area in their concession where an archaic spider (Liphistius kanthan) and a cave gecko (Cyrtodactylus guakanthanensis) are known to live. Another example is Holcim Indonesia, which agreed to a 200-metre buffer around a cave area inside their concession.
For Whitten, it’s been 21 years now since Hon Chong’s beleaguered hills were first brought to his attention. Time is fast running out on its remarkable communities of limestone-restricted biodiversity, which the IUCN quotes as “probably one of the worst cases on Earth of multi-species extinctions under direct human action”.
Why is it so important to keep these little creatures alive? “I can only give a moral answer,” replies Whitten. “I don’t think it is right to cause the extinction of those which have survived hundreds of millions of years or so. A conscious decision to destroy a species, by continuing with business as usual, is quite a step to take.”
This piece was produced by SciDev.Net’s South-East Asia & Pacific desk.