Sahyadri ENews

The Western Ghats is a mountain range of southwest India, considered as one of the 34 Global biodiversity hotspots and also one of the world's eight “Hottest of Biodiversity Hotspots” (Ranjit Daniels, 1992; Anjum Nasreen Rizvi, 2009). This mountain range runs continuously from north to south between 8o0’ to 22o26’N latitude and 72o55’ to 78o11’E, covering 6 states, Gujarat, Maharashtra, Goa, Karnataka, Kerala and Tamilnadu (Fig. 4.1). It covers a distance of 1500 km from Tapti River in the north to Kanyakumari to the south and an area of 1,64,280 sq.km. This continuous mountain range is being interrupted by the 30 km wide Palghat Gap at the latitude around 11̊ N (Ranjit Daniels, 1992; Kasturirangan, 2013).
Altitude of Western Ghats ranges from 0 to 2674 m above sea level with the width ranging from 10km to 200km at the narrowest point to the widest point (Ranjit Daniels, 1992; Kasturirangan, 2013) (Fig. 4.2). The hills of greater height (1000-2000m) are seen between 8-13oN and 18-19oN. The peaks over 2000m are found only in the Nilgiris, Palanis and Anamalais. The Nilgiris and Palanis are spurred from the main hill chain which extends the Western Ghats eastwards to 78oE. A narrow coastal strip separates the Western Ghats from the Arabian Sea. The width of the coastal strip varies from 30 to 60 km (Ranjit Daniels, 1992).

Western Ghats region has an annual average rainfall of 2500 mm. Southwest monsoon brings rainfall in the Western Ghats region in the months of June and October. Hence it is the wettest season in the Western Ghats. Southern latitudes of Western Ghats experience prolonged rainy season due to pre-monsoon and winter showers. Thus the southern Western Ghats has a shortest dry period (2-5 months) and in the northern regions dry period varies from 5 to 8 months. Mean temperature of Western Ghats region ranges between 20 and 24oC. However, it shows fluctuations in according to seasons. In summer, temperature rises beyond 30oC and it falls to 0oC during winter in the higher hills.
The Western Ghats forms an important watershed for the peninsula with a large number of streams and rivers. Due to the prolonged rainy season and steeper hills in the southern region, torrential and perineal hill streams seem to be common. There are 38 east-flowing and 27 west-flowing major rivers originate from the Western Ghats. The west-flowing rivers drain into the Arabian Sea and the east-flowing rivers merge into one of the three major river systems, Cauvery, Krishna, Godavari, and then joins to Bay of Bengal (Dahanukar et al., 2004). These river mouths are acting as a rich habitat for diverse flora and fauna (Mesta et al., 2013).
Western Ghats has been classified into different ecological zones such as wet evergreen forests, dry evergreen climax forests and deciduous climax forests (Ramesh, 2001). It includes different vegetation types like tropical wet evergreen forest, montane stunted evergreen forest (Shola) and grassland, lateritic plateaus, moist and dry deciduous forests, dry thorn forests and grasslands (Raghavan et al., 2012). The vegetation becomes drier from west to east across the hills. Lower elevations on the eastern side contain tropical dry deciduous and thorn forest due to the less availability of rain (<1200m). While tropical moist deciduous forests are more in well-watered areas. With increasing elevation, tropical wet evergreen rainforest appears along the higher slopes and ridges. The western aspect of the hills tends to have mostly tropical moist deciduous and wet evergreen forest types at lower elevations (Champion & Seth, 1968).
Western Ghats is the natural habitat for endemic flora and fauna. 5000 species of flowering plants were reported from the Western Ghats region, among that Artocarpus hirsutus, Artocarpus heterophyllus, Acacia nilotica, Acacia catechu, Pinanga dicksonii, Vateria indica are some of the dominant tree species. 139 mammal species, 508 bird species, 179 amphibians, 290 species of freshwater fishes, 174 species of Odonates, 269 Land snails, and 331 butterfly species have been recorded from the Western Ghats region. Out of which at least 325 globally threatened species occur in this region (Myers et al., 2000).
Western Ghats is not only the abode for some of the world’s unique fauna, flora and fungi, but also has highest human population. It is more than 300 humans per sq.km, which is higher than that of other hotspots, posing serious challenges to conservation endeavour in the Western Ghats (Molur 2009). It includes 2 Biosphere Reserves, 13 National Parks, and several Wildlife Sanctuaries. Nilgiri Biosphere Reserve is spread over 5,500km² covering the evergreen forests of Nagarahole, deciduous forests of Bandipur National Park and Nuguin Karnataka and adjoining regions of Wayanad, Mudumalai National Park and Mukurthi National Park of Kerala and Tamilnadu forming the largest contiguous protected area (Myers et al., 2000).