Assam cascade frog test for Himachal stream water flow impact

Study on Assam cascade frog in Western Himalayan streams reveals correlation between water flow and species abundance.

GUWAHATI

A frog with an Assam connection has helped scientists from the Wildlife Institute of India (WII) gain insights into how water flow impacts the presence and abundance of the species in Western Himalayan streams.

Saurav Chaudhary and Salvador Lyngdoh of the WII’s Department of Landscape-Level Planning and Management published their findings in a study titled ‘Spatially Explicit Capture-Recapture-based Assessment of Population and Density of an Endemic Himalayan Stream Frog’.

The duo studied the Amolops formosus, commonly known as the Assam cascade or hill stream frog, in two streams – the Chauras and the Kanda – in the Chauras and Chhogtali beats of the Churdhar Wildlife Sanctuary in Himachal Pradesh’s Sirmour district to acquire information about the correlation of different water parameters with the abundance and density of the population of a species.

Cascade or torrent frogs of the genus Amolops comprise 72 distinct species distributed throughout the hilly regions with fast-flowing streams in southern and Southeast Asia. Amolops are highly adapted to fast-flowing hill streams because they have adhesive disks on the tips of their digits with circum-marginal grooves that help them stick to rocks and other substrates.

The Assam cascade frogs, 51 individuals of which the researchers found at elevations of 1,000 to 2,508 metres above sea level, are unusual amphibians distributed across the Himalayan belt in India and found in high-flowing and gradient streams of northern Bangladesh, Bhutan and Nepal. This species can be used as an indicator for the long-term monitoring of the condition of hilly streams.

“Our study provides the first baseline information about the population status through robust methods of this rare and endemic hill frog from the Himalayas. We used a non-physical, least stressful approach for studying the population of the species,” the paper read.