Anamalai Rain-forest Expedition along Western Ghats

Western Ghats

Along the west coast of India, from the River Tapti to the southern tip of the Indian peninsula, near Kanyakumari, runs the 1,600-km-long chain of hills called the Western Ghats. From the dawn of the Tertiary era at least, some 65 million years ago, the great scarp of the Western Ghats has been a characteristic feature of the Indian peninsula, then a triangular wedge of land moving towards its great collision with the Asian landmass resulting in the genesis of the Himalaya. Undoubtedly, the environment and the plant and animal species found on the land were different then. Prior to the Western Ghats great Cretaceous–Tertiary extinction, the land contained dinosaurs, forms peculiar to India as well as those similar to the dinosaurs of Madagascar and South America. There were similarities with the present-day too: rainforest trees such as Bischofia, Canarium, Elaeocarpus, and Persea, typical of the wet evergreen rainforests of today, occurred then as now, as evidenced from fossil pollen records.

The Western Ghats has attained recognition as one of the biologically unique areas for conservation in the world. Biologists have included it among the 34 hotspots of biological diversity in the world because of the large number of plant and animal species it contains, including hundreds that are not found elsewhere in the world. In fact, along with Sri Lanka, the Western Ghats is placed among the eight ‘hottest’ of the hotspots. The Western Ghats has also been recognized as one among the 200 globally most-valuable Eco regions for the conservation of the diversity of life on Earth.

Over 4,000 species of plants and nearly 1,000 species of terrestrial vertebrates (amphibians, reptiles, birds, and mammals) are known from the Western Ghats. The diversity of species can be largely attributed to the pronounced variation in environment as one goes from south to north, west to east (windward to rain shadow), and low to high elevations (foothills to 2,600 m). Although the Western Ghats receives precipitation from two monsoons, the southwest or summer monsoon (June to September) and the northeast or winter monsoon (October to January), the rainfall is distributed unevenly. The northern reaches do not receive rainfall from the northeast monsoon and have a long dry season of 5 – 8 months duration. The southern Western Ghats region, south of the Palghat Gap, has a shorter dry season, receiving precipitation from both monsoons. This region is also biologically and topographically more diverse than the northern Ghats.

Like many other regions of the world that are biologically rich and crucial for conservation, the Western Ghats today faces increasing degradation and loss of habitats, and a number of other threats to the survival of wild species. This is not surprising as, among the global hotspots, this is the hotspot with the highest human population density. Biologists have estimated that, of the original extent of 182,500 km² of natural or primary vegetation that existed in the Western Ghats and Sri Lanka, only 12,450 km² or 6.8% remains. The pace of loss of forest cover intensified during the pre-Independence period under British rule as forests were exploited for timber and converted to extensive plantations of timber, tea, coffee, cardamom, rubber, and pepper. Forest loss continued after Independence due to the continuation of such changes as well as due to agriculture, development, and the creation of large dams and reservoirs for hydroelectric power and irrigation. Between 1920 and 1990, forest cover declined by 40% with a four-fold increase in the number of fragments.

Few areas remain in the Western Ghats with large unbroken stretches of natural tropical rain-forest vegetation; most areas are highly human-altered landscapes dominated by plantations and developed areas with only fragments of forests remaining such as this Valparai region.

Anamalai Hills

The Anamalai (which in Tamil means the elephant hills) ranges is a major conservation area in the southern Western Ghats. The ranges occur just south of the Palghat gap and are linked with the Nelliampathy hills towards the west, the Palni hills toward the southeast, and the Eravikulam, High Wavy and other ranges towards the south. A number of Protected Areas span this region, including the Anamalai Tiger Reserve (987 km²) in the Anamalai hills, Eravikulam WLS (97 km²), Chinnar WLS (90 km²), Parambikulam WLS (274 km²), reserved forests, and the new Kodaikanal WLS in the Palni hills. Thus the Anamalai hills, covers a large forested region of great significance for conservation in the Western Ghats.

The Anamalai Tiger Reserve earlier known as the Anamalai Wildlife Sanctuary (987 km²) lies almost centrally amidst the above-mentioned Protected Areas in the Anamalai hills. The altitude within the sanctuary ranges from 220 m in the foothills along the northern fringes to 2,513 m atop Thanakkanmalai in the Grass Hills at the southern portion of the reserve. The region is drained by perennial rivers such as the Konalar, Varagaliar, Karuneerar, Chinnar, and Amaravathi. A number of reservoirs (Aliyar, Upper Aliyar, Kadamparai, Upper and Lower Nirar, Thirumurthy, and Parambikulam drain at least partly into the Anamalai Tiger Reserve.

Map of the Anamalai Hills

Although a large area of tropical rain-forest occurs within the sanctuary, much of it occurs as fragments on private lands on the Valparai plateau. The Valparai plateau containing plantations, estates, and fragments lies centrally amidst the conservation areas mentioned earlier. The topography on the plateau is undulating, occasionally rising into minor peaks, and ranging in altitude from 900 m to 1,500 m. At least 40 rain forest fragments, including 34 on private lands occupying a total of over 750 ha have been identified so far in and around this area. The plantations and fragments are surrounded on all sides by Protected Areas that contain significant wildlife populations. Many species move through this fragmented landscape between conservation areas, including large mammals such as Asian elephant, tiger, leopard, and dhole, and birds such as Great Horn-bills.

Nilgiri Tahr:  (Nilgiritragus hylocrius)

The only mountain goat that is known to naturally occur in tropics rather than in temperate regions, the Nilgiri Tahr makes it home in the unique, high elevation, grassy peaks of the shola-grassland ecosystems above 1500 m in the Western Ghats.

Lion-tailed Macaque : (Macaca silenus)

The flagship primate of the rainforests of the Western Ghats, the Lion-tailed Macaque is a critically endangered, endemic species. They are usually seen in small troops in the canopy feeding on fruits and foraging for insects.

Indian Giant Squirrel : (Ratufa indica)

An Indian Giant Squirrel, the largest tree squirrel in Asia, looks out of its arboreal home. These squirrels feed on fruits, seeds and leaves and uses leafy branches as well as strips of bark as nesting material. They are common all across the Western Ghats.

Brown Palm Civet: (Paradoxurus jerdoni)

An endemic civet of the Western Ghats, the Brown Palm Civet is predominantly a fruit-eater and an important seed dispersing agent in the tropical rainforests. They are highly arboreal and nocturnal in habit.

Nilgiri Langur: (Trachypithecus johnii)

An endangered and endemic primate, the Nilgiri Langur makes its only home in the moist forests of the Western Ghats. Although wiped out from many areas by people, the Nilgiri Langur is making a slow and steady comeback with increased protection.

Maiden-hair Fern: (Adiantum sp.)

These are a group of diverse herbaceous plants that typify and indicate the health of wet tropical forests... The fruiting bodies or sori form interesting patterns and help in their identification.

Impatiens Flowers: (Impatiens sp.) rock balsam plant

Impatiens derives its name from the plant’s seed pods. When the seed pods mature, they explode when touched (as if they were “impatient” to open), dispersing the seeds several meters away. Most of these Impatiens species are endemic to the Western Ghats.

Malabar Whistling Thrush: (Myophonus horsfieldii)

Also known as the whistling schoolboy, this thrush is found to favor steams and riverine vegetation in the wet tropical forests. People often wake up to the lovely songs of this bird.

Large-scaled Pit Viper: (Trimeresurus macrolepis)

Large-scaled Pit Vipers are one of the smallest venomous snakes in the Western Ghats. These pit vipers wait by the streams and with their heat sensing pits in front of their eyes, catch prey whenever they pass-by.

As the Western Ghats are at their widest in this region, there is considerable variation in climate from west to east. The western windward slopes and upper reaches receive around 3,500 mm (up to around 5,000 mm) of rain annually and typically contain tropical wet evergreen forests. The extreme eastern parts have tropical dry deciduous forests, giving way to tropical dry thorn as the hills meet the plains—these areas may receive as little as 500 mm of rain annually.

During colonial times, the Anamalai hills was an important timber-extraction area. Extraction began around the 1830s and continued intensively until it declined around 1862. Reservation of the forest tracts began from 1883. Logging continued in the northern part of the sanctuary area until 1976. Tea and coffee estates burgeoned in the hills around the Valparai area from the mid 1800s. A coffee estate at Poonachi was recorded as existing as early as 1858. The Waterfall and Waverley estates were the earliest to be established on the Valparai plateau in 1864. By 1900, the area under coffee, tea, and cardamom was 1,155 acres, 545 acres, and 843 acres, respectively. Over a dozen estates had been established by 1930. The process continued even after independence. At the present day, the reserve contains 18,032 ha of tea, coffee, and cardamom estates and 3,717 ha of cinchona (half of which has been converted to tea.

The condition of the forests around 1897 can be judged from the following quote from Congreve (1942): “There were miles and miles of evergreen forest, with a few main paths running through it made by the huge herds of elephants which roamed there in the dry weather…The only inhabitants were a few Kaders living here and there in small communities, collecting minor forest produce, and making small clearings of hill rice, maize, and ragi, on which they largely lived. The only method of leaving the district was to walk to the foot of the hills, and then proceed by bullock cart to Coimbatore.” Today, the situation is radically different. The Valparai plateau has only fragments of rainforest that are virtually islands surrounded by plantations of tea, coffee, and Eucalyptus. This area has a small town (Valparai) and a human population of about 100,000 people, including estate labourers, businessmen, government staff, and dependents, scattered across the town and the 54 estates around it. Indigenous tribal people, belonging to six main tribal communities (Kadars, Malasars, Malamalasars, Eravalars, Pulaiyars, and Muduvars) live within the area, scattered in many settlements . A good network of roads connects the settlements, factories, and estates. The main road from Pollachi to Chalakudi, busy with traffic, passes through many fragments on the Valparai plateau. A large number of people depend on the rain-forests for fuel-wood and many fragments have become noticeably degraded due to the chronic extraction. Removal of trees from fragments and conversion of shade-coffee estates to tea plantations are other forces of change inimical to conservation in the region.