Structure and Composition of Vegetation along an Altitudinal Gradient in Outer Seraj Region of Kullu District of Himachal Pradesh, India

Abstract

Phytosociological characteristics of tree species along an altitudinal gradient in Anni block of Outer Seraj area of Kullu district was documented and analyzed during the period 2022 and 2024. The vegetation composition of plant species in three elevation ranges has been determined using a variety of phytosociological and diversity indices. A total of 101 species (33 trees, 28 shrub species and 40 herb species) belonging to 90 genera and 46 families were recorded in the study area and dominant families were Rosaceae (12 spp.), Fabaceae (11 spp.), Pinaceae and Asteraceae (5 spp. each), Sapindaceae, Lamiaceae and Solanaceae (4 spp. each), Polygonaceae and Urticaceae (3 spp. each). Significant variations in species composition and phytosociological traits were observed among the three elevation zones. As per studied diversity indices, the medium altitudinal zone (Zone II) showed the highest species diversity and richness for shrubs, whereas the lower altitudinal zone (Zone I) showed the highest species richness for trees and shrubs. The value of Shannon diversity index was recorded between 0.70 to 2.80 for trees, 0.66 to 1.90 for shrubs and 0.52 to 1.65 for herbs. The concentration of dominance values recorded for the study site was 0.13-0.65 for trees, 0.17-0.54 for shrubs and 0.21-0.99 for herbs. Species richness ranged from 1.65 to 5.71 for herbs, 1.63 to 7.68 for shrubs and 3.42 to 11.39 for trees. Most of the recorded species exhibited contagious distribution across all zones except one species (Thymus linearis) that exhibited random distribution. This study provides crucial baseline information on phytosociological diversity of plant species in Outer Seraj area of Kullu district and conservation of biodiversity in the Outer Seraj region.