Abstract
The baseline ecological exploratory studies of floristically rich areas like the western Himalaya are very important to determine the diversity variations. Based on research gaps detected in ecological literature of the western Himalayan forests of Sudhan Gali and Ganga summit, the study area is revisited. Plots data was collected during 2016, and advanced multivariate statistical tools were used to analyze it. Some of multivariate tools including permutation test, indicator species analysis and variation partitioning (partial CCA) were used for the first time in the area. The results of hierarchical clustering and permutation test revealed that there were four ecologically meaningful vegetation groups (1. Berberis-Micromeria-Desmodium (BMD), 2. Pinus-Rubus-Persicaria (PRP), 3. Viburnum-Abies-Dryopteris (VAD) and 4. Sibbaldia-Thymus-Bistorta (STB) associations) in the area. A significant (p <= 0.05) pairwise compositional difference of all the detected plant communities was observed. The results of canonical correspondence analysis (net effect) depicted that all the studied environmental variables were significantly important, and explains about 73.1% variations in the species data. The higher (r > 0.9) species-environment pseudo-canonical correlations values for the first four CCA-axes revealed that the selected explanatory variables were determinants of the response (species) data variations, and the high values for the CCA axes 2 to 4 indicated that there was no single dominant environmental gradient in this part of the western Himalaya. The highest beta diversity value of Himalayan alpine scrubland at the Ganga summit depicted that even a minor variation in environment affects the high altitude vegetation more rapidly than the vegetation of low elevation areas. The vegetation of the study area is under continuous deterioration, and this exploratory work can be used as a baseline study for the future management, sustainable use, and conservation programs in the area.