The idea of Biosphere Reserves (BR) was initiated by UNESCO in 1973-74 with the intention of considering in-situ representative systems under natural conditions and in suitable sizes so as to ensure unaided perpetuation and unhindered evolution of living resources. BRs are a set of unique ecosystems identified on the basis of their biodiversity, undisturbed flora & fauna effectiveness as a conservation unit With a total area of 328 million hectares, India is one of the 12 mega-diversity countries. There are about 45,000 species of plants and 81,000 species of animals (NFAP, 1999). To maintain the rich biological diversity, 11 BRs, with a geographical area of 4.76 m ha (1.45% of the geographical area of the country), have been created during the period 1986 to 1999

Collection, synthesis and dissemination of various types of information of the BRs is very important from conservation and management point of view. Forest cover is one of the most important parameters of BR that needs monitoring at regular interval to check the results of the conservation efforts. One of the quickest and most accurate techniques for assessing forest cover is satellite based remote sensing.

A comprehensive study of the six BRs, whose area and boundaries are available has been made by FSI, through visual interpretation of satellite imagery on 1:250,000 scale. To assess the changes in the vegetation cover of the biosphere reserves the satellite data of two different periods 1991 and 1999 have been used.

The changes that have occurred in different categorizes of forest cover between 1991 and 1999 is given in the following tables.