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Site description (2004 baseline)
Avalanche, a part of the Nilgiri Hills, lies in the extreme northwest of Tamil Nadu, on the interstate boundaries with Karnataka and Kerala. Avalanche Reserve Forest encompasses an area of 7,846 ha. The terrain is undulating with a few remnant patches of grassland and sholas, the latter confined to the folds of hills and depressions. There are numerous streams draining into the reservoirs of the Canada and Emerald Dams that have submerged a considerable area. The climate is generally cool throughout the year, with frost formation mainly during November and December. This site forms one of the key areas for the conservation of many endemics and threatened bird species of the Western Ghats, such as the Rufous-breasted or Nilgiri Laughingthrush Garrulax cachinnans. Increasing anthropogenic pressure from the nearby settlements is a cause of concern for this IBA. The vegetation cover mainly constitutes monoculture plantations of exotics Wattle Acacia mearnsii, Blue Gum Eucalyptus globulus and Pine Pinus patula. The vegetation can be classified into three major types namely, Southern Montane Wet Temperate Forest (Shola), grasslands and exotic plantations. Details of the flora are included in the authoritative works of Gamble (1915-25) and Fyson (1915-20). Southern Montane Wet Forests classified by Champion and Seth (1968), generally found above 1,800 m, are common in Avalanche and consist of medium sized evergreen trees upto 20 m. Such forest patches usually occur as a rule at the heads of streams in the folds of converging slopes and include species of both tropical and temperate regions. Several genera of distinctly Himalayan origin, such as Rhododendron, Hypericum, Rubus, Lonicera, Gaultheria and Pittosporum are common. Over the past hundred years, sholas have been converted to monoculture plantations or tea estates and this continued up to the late 1970s. Now, fortunately this has been stopped and the remnant sholas have been protected. Grasslands in Avalanche Reserve Forest were the worst affected by plantations, as a result of which hardly any undisturbed grassland remains. Fragments of grassland are seen between the mosaic of plantations and shola patches. During monsoon, the natural grasslands harbour many species of Balsam and Orchids, some rare and endemic. Systematic plantation of exotic species began in 1953, coverning about 70% of this IBA; largely Wattle, Eucalyptus, Pine and Tea were planted. Plantation is proportionally the largest vegetation type in Avalanche. Thickets of Wattle and stands of Pine are seen everywhere. Tea plantations are mainly found in the area from Murlimunth towards Emerald village.

Key biodiversity

AVIFAUNA: This is one of the most important bird areas in the Nilgiris. The shola in this IBA harbours several endemic and habitat-specialist bird species such as the Nilgiri Laughingthrush, White-bellied Shortwing Brachypteryx major and Nilgiri Wood -Pigeon Columba elphinstonii. Grassland species of conservation interest include the Nilgiri Pipit Anthus nilghiriensis, which is a common species in suitable habitats in the IBA. The remnant grasslands also provide foraging ground to many raptors such as the Common Buzzard Buteo buteo, White-eyed Buzzard Butastur teesa, Common Kestrel Falco tinnunculus, and Black-shouldered Kite Elanus caeruleus, to name a few. The Common Kestrel breeds in this IBA. The plantations in this IBA are the least important habitat type, and support mainly generalist species such as the Grey Tit Parus major, White-eye Zosterops palpebrosus and warblers in winter (Zarri et al. 2002). The wattle plantation in Avalanche also supports a small wintering population of the Kashmir Flycatcher Ficedula subrubra. During a recent survey of this species in the Nilgiris Upper Plateau, 12 of the 16 individuals birds sighted altogether were recorded from this IBA (Zarri and Rahmani, in press). The Woodcock Scolopax rusticola, which was once a prized game bird, has severely declined over the last few decades in most parts of its range in India. It is still found in Avalanche, but is an extremely rare winter visitor. The water reservoir in this IBA is devoid of vegetation, and supports no significant bird species except a few Common Sandpipers Actitis hypoleucos and Large Cormorants Phalacrocorax carbo. Fish fauna is limited to two species, one of them the highly prized game fish, Rainbow Trout Salmo gairdneri, which was successfully introduced here in 1911 to the detriment of many endemic species. The site lies in the Western Ghats Endemic Bird Area (EBA), where Stattersfield et al. (1998) have listed 16 restricted range species. Eight of them are found in this IBA. All the five restricted range species associated with Wet Temperate sholas and Subtropical Broadleaf Hill Forest (Stattersfield et al. 1998) are found, which proves that some shola habitat is still available despite extensive plantation in the past. The occurrence of such species also necessitates further protection of the site. Avalanche is located in Biome-10 (Indian Peninsula Tropical Moist Forests). Fifteen species represent this biome. Only two species, the White-cheeked Barbet Pomatorhinus horsfieldii and Indian Scimitar Babbler Pomatorhinus horsfieldii have been recorded to date. The Indian Scimitar Babbler is much widely distributed, so it may not be the best example of this biome. The site is an important wintering area for many birds that are listed in other biomes such as Tickell’s Leaf Warbler Phylloscopus affinis, Large-billed Leaf Warbler Phylloscopus magnirostris, Brownbreasted Flycatcher Muscicapa muttui, Blue-headed Rock-thrush Monticola cinclorhynchus and Indian Blue Robin Luscinia brunnea.

OTHER KEY FAUNA: Troops of Nilgiri Langur Trachypithecus johni are frequently seen all through this IBA, while Bonnet Macaque Macaca radiata is occasionally present near the settlements. Among the large cats, Tiger Panthera tigris and Leopard P. pardus are sighted, the leopard being more frequent. Several other small mammals, such as Jungle Cat Felis chaus, Brown Palm Civet Paradoxurus jerdoni, Striped-necked Mongoose Herpestes vitticollis, and Common Mongoose Herpestes edwardsii have also been recorded. Packs of Wild Dog Cuon alpinus, and Golden Jackal Canis aureus are also to be seen. Nilgiri Marten Martes gwatkinsi is rarely seen, perhaps because of its elusive behaviour. Among the herbivores, Sambar Cervus unicolor and Barking Deer Muntiacus muntjak are fairly common, while Nilgiri Tahr Hemitragus hylocrius can also be sighted near cliffs.

Acknowledgements
Key contributor: Ashfaq Ahmed Zarri.

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Recommended citation
BirdLife International (2024) Important Bird Area factsheet: Avalanche (Nilgiri) (India). Downloaded from https://datazone.birdlife.org/site/factsheet/avalanche-(nilgiri)-iba-india on 26/11/2024.