Introduction

Three watersheds  viz., Mandhala, Moolbari and Me Gad representing lower, middle and upper Himalayas respectively in the state of Himachal Pradesh were chosen by the Ministry of Science and Technology, Government of India for implementing a coordinated, multi disciplinary and multi institutional program “Bio-geo database and ecological modeling for Western Himalayas”.  The Himalayas are rich in natural resources; however over the years, Himalayan environment is increasingly being threatened due to various unplanned human activities with excessive exploitation of natural resources. It is imperative to develop strategies for sustainable management to commensurate with the increasing human pressure on the natural resources.

Himachal Pradesh is an important part of Western Himalaya covering about 11% of total Himalayan land mass. Mountain ranges in the state include Shivaliks and Trans–Himalayas with altitudes ranging from about 350–7000 m above mean sea level. Winter (December–February), pre-monsoon (March–June), monsoon (July–September) and post-monsoon (October–Novermber) are major seasons in the region. Precipitation varies from snowfall to rainfall that ranges from 1000-2500 mm. Temperature varies from sub-zero ranges of -30° to -40°C (in winter) at higher altitudes, whereas in the plains it ranges between 8° to 40°C. Many rivers like Beas, Sutlej, Chenab, Ravi and Yamuna originate from this region.  The climate is distinguished in three axes: (i) a vertical axis determined by the effect of altitude on temperature; (ii) a transverse axis determined by topography along which rain shadow effects cause decreasing precipitation and increasingly extreme (continental) temperature fluctuations from SW to NE across the main ranges; (iii) a longitudinal axis determined by a geographical trend of decreasing monsoon precipitation (June September) and increasing winter snowfall (December-April) from SW to NW along all the ranges. The third axis is important in determining major ecological trends over the entire length of the Himalayan chain, but it is less important than the other two axes in determining the ecology of localities within Western Himalaya (Gaston et al.,1983).

The vegetation of Himachal Pradesh can be broadly classified into (i) tropical-below 1000 m, (ii) sub-tropical- between 1800-2000 m, (iii) temperate- between 1800- 3500 m, (iv) subalpine- between 3500-4000 m, and (v) alpine- above 4000 m. However, these may overlap depending upon the location, topography and climatic conditions. The enormous variations in the altitude, latitude and longitude of the Himalayas have added to the multiplicity of habitats and provide diverse microclimates and ecological niches for all the living beings. Also, the Western Himalayan flora is species deficient whereas, the eastern Himalayan flora is species rich (Chowdhery, 1999). The Western Himalayan region which includes Jammu and Kashmir, Himachal Pradesh and hilly regions of Uttar Pradesh receives very less rain compared to its eastern counterpart, the Eastern Himalaya. As a result the Western Himalayan flora in due course of time has evolved and established itself as drought resistant and cold loving while the Eastern Himalayan flora has developed into moist evergreen type. The focus of the current communication is to assess the diversity and distribution of flora and fauna in select watersheds of Western Himalaya.

Objectives
The major objectives of this study are to assess: