Abundant snails show Bhutan’s environment is healthy

Research: A team of three researchers discovered a new mollusc species and recorded a total of 150 species in the country.

The team is looking for possible literature on several other samples, which the team believes are new.

National Biodiversity Centre (NBC) researcher Pema Leda said, “It’s a lengthy process.  We could complete only one so far.”

The research team began collecting species of snails from across the country from 2012.

The team consisted of one researcher each from the NBC, Ugyen Wangchuck Institute for Conservation and Environment, and Naturalis,  the National Biodiversity Centre of the Netherlands.

The lead researcher and a professor with Naturalis, Dr Edmund Gittenberger, said that snails act as hosts for parasites that are important for human health, agriculture, and livestock. They serve as ‘indicator species’ to determine the health of the natural environment.

“In a week, we could collect about 650 samples. It is that abundant,” Dr Edmund Gittenberger said. “Given the size of your country and the density, I’d say the environment is very healthy.”

However, the prevalence of species in fresh water is harmful to human health as they carry trematodes or flatworms that cause fatal liver disease called fascioliasis. Two snail species were found in Bhutan’s streams in the south.

“People in the south shouldn’t drink unboiled water as most waters were found with snails that carry the trematodes,” Dr Edmund Gittenberger said.

NBC’s programme director and a veterinarian, Dr Tashi Yangzome Dorji, said that the majority of the Bhutanese cattle have problems with liver fluke.

“In winter, cattle are fed with straw where snails are common. So the infection could be coming through them,” Dr Tashi Yangzome Dorji said.

The newly discovered snail species from Pemagatshel

The newly discovered snail species from Pemagatshel

The disease-carrying giant African land snail (GALS) was found inhabiting only in the areas close to the settlements in Gyalpoizhing, Mongar.

GALS was first spotted in 2008 near Gyalpoizhing school area, feeding on a wide range of vegetation such as crops, trees and also calcareous substances, such as concrete.

Professor Edmund Gittenberger said that conventional quarantine method of killing them might not be enough.

“We need to know why the snail, which is native of Africa, is not an issue there. Perhaps the answer lies in knowing more about it,” he said.

The research found a close bio-geographical connection between Bhutan and the Khasi hills in northern India.

NBC officials said that data on local molluscan faunas have never been published. The research team will publish a series of papers on snails to provide a general overview of the Bhutanese molluscan fauna.

NBC’s principal biodiversity officer, Sangay Dema, said that nothing is known about the molluscan fauna of the country.

“All records of molluscs of Bhutan turned out to be incorrect by modern standards,” she added.

While several localities in Sikkim, India, for instance, were reported from western Bhutan, both in old collections and in the old literature.

“As far as known now, only a single molluscan species, Phaedusa (P.) bhutanensis (Clausiliidae), was ever described from the country by Nordsieck in 1974,” Professor Edmund Gittenberger said.

Bhutan Trust Fund for Environment Conservation funded the project.

Tshering Palden

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