Riparian Phytodiversity Status of Pristine Bhilangana Valley of Garhwal Himalaya: An Undocumented Retrospective Hitherto

The present study was conducted for quantitative and qualitative characteristics of floristic diversity at the species level along environmental gradients of major and minor streams of the Bhilangana River in the Tehri District of Garhwal Himalaya. The stratified random sampling design was used for the study purpose. A total of 150 nested quadrats each with a size of 20 m×20 m for tree species and within each major plot, 5 m×5 m and 1 m×1 m sub plots were nested for shrubs and herbaceous species respectively. A total of 212 plant species belonging to 158 genera and 87 families were recorded. On the basis of important value index (IVI), Pinus roxburghii, Rhododendron arboreum, Quercus leucotricophora, Quercus semecarpifolia and Lyonia ovalifolia were dominant tree species within the entire basin area along the stream courses. The Shannon index and Simpson index values recorded for trees, shrubs and herbs were 2.64 (0.13), 1.04 (0.87) and 4.25 (0.019) respectively. This study provides comprehensive information on the species diversity of different vegetation life forms in the riparian zone of the Bhilangana valley.