The Western Ghats (Kannada ಸಹ್ಯಾದ್ರಿ, Marathi / Konkani- सह्याद्री Sahyadri, Malayalam സഹ്യപര്വ്വതം, Tamil மேற்கு தொடர்ச்சி மலை) also known as the Sahyadri mountains, is a mountain range along the western side of India. It runs north to south along the western edge of the Deccan Plateau, and separates the plateau from a narrow coastal plain along the Arabian Sea. The range starts near the border of Gujarat and Maharashtra, south of the River Tapti, and runs approximately 1600 km through the states of Maharashtra, Goa, Karnataka, Tamil Nadu and Kerala ending at Kanyakumari, at the southern tip of India. About sixty percent of the Western Ghats are located in the state of Karnataka.
These hills cover 60,000 km² and form the catchment area for a complex of river systems that drain almost 40% of India. The average elevation is around 1,200 meters. The area is one of the world’s ten "Hottest biodiversity hotspots" and has over 5000 species of flowering plants, 139 mammal species, 508 bird species and 179 amphibian species. At least 325 globally threatened species occur in the Western Ghats.
Smaller ranges, including the Cardamom Hills and the Nilgiri Hills, are in northwestern Tamil Nadu. Nilgiri Hills is home to the hill station Ootacamund. In the southern part of the range in the Anaimalai Hills, in western Tamil Nadu and Kerala, Ana Mudi is the highest peak in India, south of the Himalayas. Chembra Peak , Banasura Peak , Vellarimala and Agasthya mala are also in Kerala. Doddabetta is . Mullayanagiri is the highest peak in Karnataka . The Western Ghats in Kerala is home to many tea and coffee plantations. The major gaps in the range are the Goa Gap, between the Maharashtra and Karnataka sections, and the Palghat Gap on the Tamil Nadu/Kerala border between the Nilgiri Hills and the Anaimalai Hills.
The northern portion of the narrow coastal plain between the Western Ghats and the Arabian Sea is known as the Konkan Coast or simply Konkan,the central portion is called Kanara and the southern portion is called Malabar region or the Malabar Coast. The foothill region east of the Ghats in Maharashtra is known as Desh, while the eastern foothills of central Karnataka state is known as the Malnad region. The largest city within the mountains is the city of Pune (Poona), in the Desh region on the eastern edge of the range. The Biligirirangan Hills lies at the confluence of the Western and Eastern Ghats.
The mountains intercept the rain-bearing westerly monsoon winds, and are consequently an area of high rainfall, particularly on their western side. The dense forests also contribute to the precipitation of the area by acting as a substrate for condensation of moist rising orographic winds from the sea, and releasing much of the moisture back into the air via transpiration, allowing it to later condense and fall again as rain.
The majority of streams draining the Western Ghats and joining the Rivers Krishna and Cauvery carry water during monsoon months only and have been dammed for hydroelectric and irrigation purposes. The major reservoirs are: Lonavla and Walwahn in Maharashtra; V.V. Sagar, K.R. Sagar and Tungabhadra in the Malnad area of Karnataka; Mettur, Upper Bhawani, Mukurti, Parson's Valley, Porthumund, Avalanche, Emarold, Pykara, Sandynulla and Glenmorgan in Tamil Nadu; and Kundallay and Maddupatty in the High Range of Kerala. Of these the Lonavla, Walwahn, Upper Bhawani, Mukurti, Parson's Valley, Porthumund, Avalanche, Emarold, Pykara, Sandynulla, Glenmorgan, Kundally and Madupatty are important for their commercial and sport fisheries for trout, mahseer and common carp.
The Western Ghats form one of the three watershed of India, feeding the perennial rivers of India. Important rivers include the Tambaraparani River, Godavari, Krishna, and Kaveri. These rivers flow to the east and drain out into the Bay of Bengal. The west flowing rivers, that drain into the Arabian Sea, are fast-moving, owing to the short distance travelled and steeper gradient. Important rivers include the Mandovi and Zuari. Many of these rivers feed the backwaters of Kerala and Maharashtra. Rivers that flow eastwards of the Ghats drain into the Bay of Bengal. These are comparatively slower moving and eventually merge into larger rivers such as the Kaveri and Krishna. Smaller rivers include the Chittar River, Bhima River, Malaprabha River, Manimuthar River, Kabini River, Kallayi River, Kundali River, Pachaiyar River,Pennar River,Periyar,Kallayi River
Fast running rivers and steep slopes have provided sites for many large hydro-electric projects. There are about major 50 dams along the length of the Western Ghats with the earliest project up in 1900 near Khopoli in Maharashtra. Most notable of these projects are the Koyna Dam in Maharashtra, the Parambikulam Dam in Kerala, and the Linganmakki Dam in Karnataka. The reservoir behind the Koyna Dam, the Shivajisagar Lake, is one of the largest reservoirs in India with a length of and depth of .
During the monsoon season, numerous streams fed by incessant rain drain off the mountain sides leading to numerous and often spectacular waterfalls. Among the most well known is the Jog Falls, Kunchikal Falls, Sivasamudram Falls, and Unchalli Falls. The Jog Falls is the highest natural waterfall in South Asia and is listed among the 1001 natural wonders of the world. Talakaveri wildlife sanctuary is a critical watershed and the source of the river Kaveri. This region has dense evergreen and semi-evergreen vegetation, with shola-grassland in areas of higher elevation. The steep terrain of the area has resulted in scenic waterfalls along its many mountain streams. Sharavathi and Someshvara Wildlife sanctuaries in Shimoga district are the source of the Tungabhadra River system.
Climate in the Western Ghats varies with altitudinal gradation and distance from the equator. The climate is humid and tropical in the lower reaches tempered by the proximity to the sea. Elevations of and above in the north and and above in the south have a more temperate climate. Average annual temperature here are around 15 °C (60 °F). In some parts frost is common, and temperatures touch the freezing point during the winter months. Mean temperature range from 20 °C (68 °F) in the south to 24 °C (75 °F) in the north. It has also been observed that the coldest periods coincide with the wettest.
During the monsoon season between June and September, the unbroken Western Ghats chain acts as a barrier to the moisture laden clouds. The heavy, eastward-moving rain-bearing clouds are forced to rise and in the process deposit most of their rain on the windward side. Rainfall in this region averages 3,000–4,000 mm (120–160 in) with localised extremes touching 9,000 mm (350 in). The eastern region of the Western Ghats which lie in the rain shadow, receive far less rainfall averaging about 1,000 mm (40 in) bringing the average rainfall figure to 2,500 mm (150 in). Data from rainfall figures reveal that there is no relationship between the total amount of rain received and the spread of the area. Areas to the north in Maharashtra receive the heaviest rainfall, but are followed by long dry spells, while regions closer to the equator receive less annual rainfall, with rain spells lasting almost the entire year.
The Western Ghats are home to four tropical and subtropical moist broadleaf forest ecoregions – the North Western Ghats moist deciduous forests, North Western Ghats montane rain forests, South Western Ghats moist deciduous forests, and South Western Ghats montane rain forests.
The northern portion of the range is generally drier than the southern portion, and at lower elevations makes up the North Western Ghats moist deciduous forests ecoregion, with mostly deciduous forests made up predominantly of teak. Above 1,000 meters elevation are the cooler and wetter North Western Ghats montane rain forests, whose evergreen forests are characterized by trees of family Lauraceae.
The evergreen Wayanad forests of Kerala mark the transition zone between the northern and southern ecoregions of the Western Ghats. The southern ecoregions are generally wetter and more species-rich. At lower elevations are the South Western Ghats moist deciduous forests, with Cullenia the characteristic tree genus, accompanied by teak, dipterocarps, and other trees. The moist forests transition to the drier South Deccan Plateau dry deciduous forests, which lie in its rain shadow to the east.
Above 1,000 meters are the South Western Ghats montane rain forests, also cooler and wetter than the surrounding lowland forests, and dominated by evergreen trees, although some montane grasslands and stunted forests can be found at the highest elevations. The South Western Ghats montane rain forests are the most species-rich ecoregion in peninsular India; eighty percent of the flowering plant species of the entire Western Ghats range are found in this ecoregion.
The area is ecologically sensitive to development and was declared an ecological hotspot in 1988 through the efforts of ecologist Norman Myers. Though this area covers barely five percent of India's land, 27% of all species of higher plants in India (4,000 of 15,000 species) are found here. Almost 1,800 of these are endemic to the region. The range is home to at least 84 amphibian species, 16 bird species, seven mammals, and 1,600 flowering plants which are not found elsewhere in the world.
The Government of India established many protected areas including 2 biosphere reserves, 13 National parks to restrict human access, several wildlife sanctuaries to protect specific endangered species and many Reserve Forests, which are all managed by the forest departments of their respective state to preserve some of the ecoregions still undeveloped. Many National Parks were initially Wildlife Sanctuaries. The Nilgiri Biosphere Reserve comprising 5500 km² of the evergreen forests of Nagarahole, deciduous forests of Bandipur National Park and Nugu in Karnataka and adjoining regions of Wayanad and Mudumalai National Park in the states of Kerala and Tamil Nadu forms the largest contiguous protected area in the Western Ghats. The Western Ghats in Kerala is home to numerous serene hill stations like Munnar, Ponmudi and Waynad. The Silent Valley National Park in Kerala is among the last tracts of virgin tropical evergreen forest in India.
These hill ranges serve as important wildlife corridors, allowing seasonal migration of endangered Asian Elephants. The Nilgiri Bio-sphere is home to the largest population of Asian Elephants and forms an important Project Elephant and Project Tiger reserve. Brahmagiri and Pushpagiri wildlife sanctuaries are important elephant habitats. Karnataka's Ghat areas hold over six thousand elephants (as of 2004) and ten percent of India's critically endangered tiger population.
The largest population of India's Tigers outside the Sundarbans is in the unbroken forests bordering Karnataka, Tamil Nadu and Kerala. The largest numbers and herds of vulnerable Gaur are found here with the Bandipur National Park and Nagarahole together holding over five thousand Gaur. To the west the forests of Kodagu hold sizeable populations of the endangered Nilgiri Langur. Bhadra Wildlife Sanctuary and project tiger reserve in Chikmagalur has large populations of Indian muntjac. Many Asian Elephant, Gaur, Sambar, vulnerable Sloth Bears, Leopard, tiger and Wild Boars dwell in the forests of Kerala.
Bannerghatta National Park and Annekal reserve forest is an important elephant corridor connecting the forests of Tamil Nadu with those of Karnataka. Dandeli and Anshi national parks in Uttara Kannada district are home to the Black Panther and normal variety of leopards and significant populations of Great Indian Hornbill. Bhimgad in Belgaum district is a proposed wildlife sanctuary and is home to the endemic critically endangered Wroughton's freetailed bat. the Krishnapur caves close by are one of only three places in the country where the little-known Theobald's tomb bat is found. Large Lesser False Vampire bats are found in the Talevadi caves.
* Trek the Sahyadris Harish Kapadia