Exploiting limestone, Silvered langurs lose their “home”: a response

Several recent newspaper articles, including one published in the December 12, 2011 edition of Tuoi Tre, draw attention to the status of the Silvered langur (Trachypithecus germaini) populations on the karst hills of Kien Luong District, Kien Giang Province. As the Tuoi Tre article states, this species is assessed as Endangered by IUCN, the International Union of Conservation of Nature, because it is believed to have undergone a decline exceeding 50% over the past 36 years (three generations, given a generation length of 12 years) due to a combination of habitat loss and hunting pressure (http://www.iucnredlist.org/apps/redlist/details/39874/0). The Tuoi Tre article also correctly acknowledges the unique biodiversity of the Kien Luong karst hills.

Indochinese silvered langur in Hon Chong

Since 2008, Holcim Vietnam Limited (HVL) and IUCN have cooperated to mitigate the environmental impacts of HVL’s quarrying operations at its Hon Chong site in Kien Luong. This has included funding to the Center of Biodiversity and Development (CBD), which is part of the Institute of Tropical Biology (ITB), to survey the area’s Silvered langur populations and to propose measures to conserve them given current and planned quarrying by HVL and several state-owned cement companies. CBD’s surveys provide a detailed understanding of the distribution of these langur populations and measures that would ensure their survival.
While addressing an issue of high conservation importance, some the Tuoi Tre article’s statements are incomplete and potentially misleading. To provide readers with a better understanding of the issues, we would like to draw attention to the following points.

First, while HVL quarried the west side of Bai Voi between 2006 and 2010, this did not directly affect the 28 langurs living in the northern part of the karst hill (known as Mo So). In 2010, HVL started quarrying vertically on the west side of Bai Voi. This quarrying is not believed to be having an serious impact on the langurs.

Second, in response to CBD’s survey results, HVL has slowed down quarrying the northern part of Khoe La, which is home to 48 langurs. The southern part of Khoe La, which supports 30 langurs, however, is being quarried by the Ha Tien II cement company. This threatens to cut the connection between the northern part of Khoe La and the mangrove belt along which the langurs could migrate to Ba Tai to the south. In 2010, CBD reported this risk to Kien Giang DONRE but no action has been taken.

Third, to assist the potential migration of the langurs to Ba Tai, HVL is supporting mangrove replanting in the mangrove belt. However, the cutting of shrimp ponds in the mangroves, which are under DARD management, threatens this connectivity. Near Khoe La, the mangrove belt is only 30 meters wide and is composed of young trees. This habitat may be too poor for the langurs to use.

Finally, as the article states, the Kien Giang PPC has assigned DONRE to establish a nature reserve to protect Kien Luong’s remaining karst hills. Since 2009, CBD has provided DONRE with extensive data and information on the area’s biodiversity to support the preparation of a feasibility study and investment plan for the nature reserve. Despite this assistance, the area is not yet legally protected. Once the nature reserve is established, HVL, recognizing that its quarrying operations have unavoidable environmental impacts, is prepared to support management of the nature reserve and its langurs. But the responsibility for creating the reserve lies with the provincial government, not with HVL or CBD.

We would also like to bring to the attention of your readers that in addition to helping to protect the Silvered langurs, HVL supports work by the International Crane Foundation (ICF) to protect the Sarus crane in the Phu My grasslands. The Sarus crane (Grus antigone) is assessed as Vulnerable by IUCN. A nature reserve has been proposed to safeguard the Phu My grasslands against further encroachment, but no decision has yet been taken. As with the karst hills, responsibility to establish a nature reserve lies with the provincial government.

The key message is that conserving Kien Luong’s unique biodiversity is a collective responsibility involving all cement companies, international and state-owned, provincial government, scientific organizations, NGOs, and local communities. A great deal is known about the area’s langurs, cranes, and other globally threatened biodiversity. But effectively protecting them requires a commitment by the provincial government to, first, work with the state-owned cement companies to adjust their quarrying plans to take into account potential langur migration routes and, second, to establish nature reserves to protect the karst hills and grasslands.

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