Vegetation and Phytogeography of the Western Ghats

Abstract

This chapter attempts to present on outline of the characteristic vegetation and phytogeographical peculiarities of the Western Ghats. The general features of the Western Ghats, the geological structure and tectonic history and the climatic characters of the region are discussed in sufficient detail by specialists in earlier chapters of this book. From the stand point of the present chapter, we may appropriately describe the Western Ghats as an important part of the monsoonland, where the vegetation is influenced more by the abundance and distribution of the seasonal rainfall than the atmospheric temperature. The western side of the Western Ghats is on the threshold of southwest monsoon and receives a rainfall of 203–254 cm, and the eastern side lies in the rain-shadow area of the Peninsula. The main types of soils met with in the Western Ghats are red soils, laterites, black soils and humid soils. The red soils are developed on the Archean crystallines and are brown, grey or black, is deficient in organic matter, phosphoric acid and nitrogen. Evergreen forest of Calophyllum, Dipterocarpus, Hopea, Myristica and Xylia are characteristic of red-soil areas. The laterites consist of 90–95% of iron, aluminium, titanium and manganese oxides and are deficient in lime and organic material, an extend up to 1600 m in the Western Ghats. Shorea and Xylia are the dominant species in lateritic soils of Western Ghats. Black soils, formed out of the basaltic Deccan lava, are deficient in organic matter, nitrogen and phosphoric acid, but generally have enough lime and potash.