Physiography and biological diversity of Rajasthan

Abstract

This introductory chapter presents an overview of the physiography, zoogeography and biodiversity of the largest state of India, Rajasthan, popularly known as the desert state. Physiographically speaking, Rajasthan is divided into four major regions, namely, the Western Thar Desert, the Aravalli Range with Vindhyan Mountains, the Eastern Plains and the south-eastern Hadoti Plateau. About 640 km long western desert region, extending over an area of 175,000 km2is covered with stable and shifting sand dunes, barren hills, rocky structural plains, sandy hammocks and low sand streaks. The entire Aravalli Range and hill tracts can be further divided into the north-eastern hill tracts or the Alwar Hills, the central Aravalli Range, the Mewar Hills and the Bhorat Plateau, the Abu Block and the Vindhyan Scarps. The eastern plains of Rajasthan include the lowlands of the Chambal plain, the Banas Plain and the middle Mahi or Chhappan Plain. The Hadoti Plateau forms a part of the Archaean Shield of the Deccan Peninsula and is divided into Vindhyan Scarpments and Deccan lava plateau. Water resources of the state which include Chambal, Banas and Mahi Rivers, their tributaries, the fresh water and salt lakes, have also been emphasised briefly in this chapter. The climatic profile of Rajasthan has been presented as a transition between two major climatic regions of India, the semi-arid east and the arid west. The unique but diverse biotic richness of the state which supports its mesmerising landscape, especially the mysterious desert having its own common, threatened and endemic flora and fauna, reserve areas and wetlands, has been thoroughly described in the chapter.