Lhonak Valley

Country/territory: India

IBA criteria met: A1, A2, A3 (2004)
For more information about IBA criteria, please click here

Area: 50,000 ha

Bombay Natural History Society
IBA conservation status
Year of assessment (most recent) State (condition) Pressure (threat) Response (action)
2003 not assessed medium not assessed
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Site description (2004 baseline)
Lhonak Valley is a Trans-Himalayan grassland in the exposed river valley of Goma Chu in northwest Sikkim, with boggy marshes, glacial lakes, barren scree slopes and glaciers. It is accessible from Thangu via the high 5,900 m pass, the Lungnak La. Snowfall makes the Valley inaccessible in winter. Goma Chu originates in North and South Lhonak glaciers and runs across the Valley to join Zema Chu. Zemu glacier is at the southern end of the Valley, as is the Green Lake. This Valley is the only known breeding area in the Eastern Himalayas of the Black-necked Crane Grus nigricollis (Ganguli-Lachungpa 1998). Lakes and marshes here are used as stopover sites for migratory waterbirds (Ganguli-Lachungpa 2002) and support populations of the Sikkim Snow Toad Scutiger sp. Vegetation is typical cold desert, with xerophytic species such as Ephedra gerardiana, herbs, grasses and sedges, aquatic weeds and many medicinal and commercially valuable plants such as Picrorhiza kurrooa and Meconopsis horridula.

Key biodiversity

AVIFAUNA: Lhonak Valley is the famed flyway of migratory waterfowl (Ali 1962). Many Vulnerable and Biome-5 restricted species breed here such as the Tibetan Snowcock Tetraogallus tibetanus, Blacknecked Crane (unsuccessful nesting attempt at Tebleh Tso, Muguthang), the Tibetan Sandgrouse Syrrhaptes tibetanus, the Güldenstädt’s Redstart Phoenicurus erythrogaster, the Hume’s Groundpecker Pseudopodoces humilis. Lesser Kestrel Falco naumanni has been infrequently recorded from this valley during the course of the Alpine Grassland Ecology Project of BNHS from 2000-2003 (U. Lachungpa pers. comm. 2003).

OTHER KEY FAUNA: Mammalian fauna includes Snow Leopard Uncia uncia, Blue Sheep Pseudois nayaur, Tibetan Wolf Canis lupus chanco, Tibetan Fox Vulpes vulpes, Siberian Weasel Mustela sibirica, Woolly Hare Lepus oiostolus and Himalayan Marmot Marmota himalayana.

Sikkim Snow Toad Scutiger sp., perhaps the highest altitude amphibian, is found in almost all lakes and waterbodies of the Goma Chu Valley.

Key contributor: Usha Lachungpa.

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Lhonak Valley. Downloaded from on 04/12/2023.