One of India’s rarest and least-known amphibians, the Dehradun Stream Frog, may have gone locally extinct, according a new study published in the Journal of Threatened Taxa. Researchers have been studying this species—Amolops chakrataensis—for the last several years, and specifically since 2023.

Their field work to find the frog featured visual and aural surveys during the day and night, over 39 days between 2023 and 2024, across multiple stream systems and seasons in the Chakrata, Uttarakhand, landscape. The researchers say they found no trace of the frog despite extensive efforts.

Lead author Vishal Kumar Prasad tells Hot Rock that they observed severe pollution in the streams where the frog lives. “A lot of people are dumping garbage in the streams and there are incidences of agricultural runoff as well, which contaminate the stream water,” Vishal Prasad says.

Plastic waste, untreated wastewater, agricultural runoff, and increasing human disturbance were observed in streams that once provided habitat for the frogs, as per their observations. “Species like Dehradun Stream frog cannot survive in that contaminated water. They cannot like breathe in water that is so polluted.” The researchers presume that pollution in the streams drove them to extirpation.

“We need to study further to say this,” he says.

It was Pranjanlendu Ray of the Zoological Survey of India who collected this frog species from a stream along the Tuni road, approximately 14 km from Chakrata Town, in 1985. It was formally described in 1992.

Vishal Prasad says Amolops chakrataensis remains one of India’s most poorly known amphibians. Holding out hope that it might just be somewhere other than its known locality, researchers say the absence of recent records does not confirm its disappearance, but “underscores the need for targeted surveys using both conventional field methods and emerging approaches such as environmental DNA (eDNA) to determine its current distribution.”

That means surveying suitable habitats other than Chakrata. Vishal Prasad says they need to sample places out of Chakrata to see whether the suitable habitat of the species has changed and whether, because of it, the species has moved to some other location.

“Our findings highlight the importance of expanding field surveys beyond the historical locality and strengthening conservation efforts for this unique Himalayan amphibian,” said Vishal Prasad.

Co-author Prof. Amaël Borzée, Co-Chair of the IUCN SSC Amphibian Specialist Group, says the study calls for the need “to strengthen conservation efforts for Himalayan amphibians through coordinated research and habitat protection.”

The researchers’ recommendations include: Targeted surveys across suitable habitats in the western Himalaya; using environmental DNA (eDNA) alongside conventional surveys to improve detection of rare species; restoring mountain stream habitats affected by pollution and habitat degradation; establishing long-term monitoring programmes; and updating conservation assessments as and when new information comes along.

So, how do local extinctions affect local biodiversity? Vishal Prasad says when a species disappears from an area, it’s not just the loss of that one species, but it also disrupts the entire ecosystem. It affects the food webs, prey-predator relationship, nutrient cycle, and the health of freshwater and forests.

This is why continuous biodiversity surveys are essential in the typical locality of the frog as well as outside in and around the area it inhabits. And habitat conservation in general across the Himalayas.

Can local extinctions become a global problem? Global extinction actually begins with local extinction. As more populations disappear across a species range, the species eventually has nowhere left to go or has no chance of surviving. The disappearance of a frog or an ant doesn’t really matter. Or does it?

“Local extinctions are early warning signs. They tell us about ecosystems that are under stress. If we act when a species disappears locally, we still have a chance to protect it elsewhere,” Vishal Prasad tells Hot Rock. 

Ignoring the warning signs risks losing that species permanently. The situation is grim for amphibians globally. According to a 2023 paper published in the journal Nature, the authors say that amphibians are the most threatened vertebrate class—40.7 per cent of species are globally threatened. 

The updated Red List Index shows that the status of amphibians is deteriorating globally, particularly for salamanders, and in the Neotropics. According to the IUCN Red List of Threatened Species, two in every five amphibian species are threatened with extinction, making them the most threatened vertebrate group.

As for what is driving these deteriorations, the Nature paper says disease and habitat loss drove 91 per cent of status deteriorations between 1980 and 2004.

Ongoing and projected climate change effects are now of increasing concern, driving 39 per cent of status deteriorations since 2004, followed by habitat loss—37 per cent. All this shows an urgent need for conservation effort to stem the tide of extinction.