Study on Algal Diversity and Physico-Chemical Parameters in Two Streams of Rohru Region in Shimla District, Himachal Pradesh, India

The present study investigates the algal diversity and physico-chemical parameters in Shikdi Stream and Dogda Stream in the Rohru region of Shimla District, Himachal Pradesh, India. Algal samples were collected during three seasons: post-monsoon, winter, and spring, and a total of 21 algal genera were identified across Bacillariophyceae, Chlorophyceae, and Cyanophyceae. Bacillariophyceae exhibited the highest seasonal stability, indicating broad ecological tolerance, whereas Chlorophyceae and Cyanophyceae displayed notable seasonal variability. Physico-chemical analyses revealed seasonal patterns: water temperature dropped in winter and peaked in spring; pH remained slightly alkaline throughout; and both total dissolved solids (TDS) and electrical conductivity (EC) were highest post-monsoon and decreased in spring, particularly in Dogda stream. Shikdi stream consistently recorded higher TDS, EC, hardness, and alkalinity, suggesting greater mineral input, possibly due to geological or anthropogenic factors. The correlation between environmental parameters and algal distribution underscores the influence of temperature, nutrient availability, and water chemistry on stream algal communities. These findings enhance the understanding of freshwater algal ecology and may inform stream monitoring, conservation, and watershed management strategies in the region.