A study to understand and assess the impact of altitudinal gradients on the floristic diversity in Shingan valley falling in Rakchham-Chitkul Wildlife Sanctuary district Kinnaur, Himachal Pradesh was carried out during the year 2008. The altitudinal gradient in the present case varied from 2800m to 4300m above msl. Total number of plant species as recorded was 118 belonging to 46 families and 87 genera. The dominant families registered were Rosaceae, Asteraceae, Lamiaceae, Ranunculaceae and Ploygonaceae. The number of tree species was 11 and 4 with the dominance of Pinus wallichiana and Betula utilis at 2800-3300m and 3300-3800m elevation respectively. The number of shrub species was 15, 13 and 6 with the dominance of Salix fragilis, Juniperus indica and Rhododendron anthopogon at the elevation of 2800-3300m, 3300-3800m and 3800-4300m. The number of herbs species was 63, 55 and 40 at 2800-3300m, 3300-3800m and 3800-4300m elevation respectively. Caltha palustris, Anaphalis triplinervis and Thymus linearis were the dominant shrub at these elevations respectively. The distribution pattern of species was mostly contiguous in all the altitude ranges. Index of diversity for herb species in different elevations ranges was 3.75, 3.66 and 3.44 for 2800-3300m 3300-3800m and 3800-4300m elevation respectively. Out of the 58 medicinal plant species as recorded from the valley, 14 species like Dactylorhiza hatagirea, Angelica glauca, Betula utilis, Podophyllum hexandrum, Picrorhiza kurrooa, Rheum australe, Taxus wallichiana, Heracleum lanatum, Polygonatum verticillatum, Rheum webbianum , Rhodiola heterodonta, Rhododendron anthopogon, Rhododendron campanulatum, Rhododendron lepidotum etc. fall in the category of threatened plants as per IUCN categorization.
