Effect of Overgrazing on the Phytosociology of Grassland Ecosystem of Aravalli Hills, Rajasthan

Abstract

Overgrazing in the plain and hillock areas of grasslands of Aravallis results in slow but inexorable deleterious change in botanical compoSition. It triggers off succession, and invariably the degenerated stage consists of inferior, less palatable annual and perennial grasses such as Tragus biflorus, Eragrostie bifaria, Eragrostis ten ella, Aristida funiclllata, Melanocencllris jacquemontii, Tripogon roxbllrghii and Bothriochloa pertusa. The Frequency Index Community Coefficient and Similarity Index is comparatively higher on hillocks rather than on plains of both protected and grazed sites. Protected site of grassland is less vulnerable to environmental vagaries due to higher value of Species Diversity Index. In plain and hillock areas of protected sites, maximum IVI was shown by Aristida funiculata and Sehima nerVOSllm, respectively, whereas, in plain and hillock areas of grazed sites, maximum pil was shown by Brachiaria ramosa and Aristida fiwiculata, respectively.