Lhonak Valley

Site description (2004 baseline):

Site location and context
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.

Pressure/threats to key biodiversity
MAIN THREATS: Accumulation of non-biodegradeable garbage; Stray dogs around army camps; Spread of disease to wildlife; Collection of wild medicinal plants; Poaching/snaring of wildlife.

Overuse of Tchopta-Lungnak La- Muguthang trail and habitat by pack animals (horses, yaks) of Assam Rifles has been reported during the Sikkim Biodiversity Strategy and Action Plan exercise of the State Forest Department. Besides large numbers of horses on the trail to ferry rations across the La (La = Pass), the attendant hazards of harvesting/collection of commercially valuable medicinal plants such Picrorhiza kurrooa, Nardostachys grandiflora and poaching of Blue Sheep and Himalayan Marmot by the travellers have been reported (Anon. 2003) The military has a permanent station here with many outposts, as there have been incidents of Tibetan refugees coming in over the passes. As a result of past airdrops, till date, one can see broken jerry cans and sacks of coir padding littering the landscape. The valley is home to seven families of nomadic Tibetan graziers or Dokpas who graze yak in a rotational system governed by traditional laws. Perhaps due to the outside sheep brought into the Valley for food for the military, a disease has killed off the entire local sheep population, and according to the local Animal Husbandry authorities, the disease may still persist in wild snails found in the marshes and wetlands of the region. Hence, there is every possibility of the disease spreading to the wild ungulates in this IBA (U. Lachungpa pers. comm. 2003.). On finishing their duration, usually over a year or two, in this difficult region, the military personnel leave their pet dogs behind. These ‘pet’ dogs survive by scavenging kitchen and mess wastes. They have multiplied over the years and have now taken to roaming in packs on the plateau in Tso Lhamo, Lhonak and Lashar, hanging around army camps during mealtimes, preying upon wildlife and have even been seen swimming in the glacial lakes after Brahminy Shelduck chicks. Of late, they have taken to preying upon domestic livestock of the Dokpas. In order to protect the wildlife of this site, these free-roaming ‘pet’ dogs need to be eliminated without further delay.

Key contributor: Usha Lachungpa.

Recommended citation
BirdLife International (2023) Important Bird Area factsheet: Lhonak Valley. Downloaded from on 22/09/2023.