STRUCTURAL AND FUNCTIONAL DIVERSITY OF PERIPHYTON COMMUNITY FROM THE WESTERN NAYAR RIVER OF GARHWAL HIMALAYA

The importance of periphyton in aquatic productivity is well accepted by the limnologists all over the world as it provides community structure and primary productivity that support a wide range of aquatic organism. River ecosystem is essential for sustenance of living organisms. Western Nayar River is one of the important sources of drinking water for the rural and urban population of Pauri district (Uttarakhand) as well as it harbors a good spectrum of biodiversity. In view of lacuna in literature, attempt has been taken to study the structural and functional community structure of Periphyton along with the important physio-chemical parameters. Monthly samples were collected from each site on the Western Nayar River for a period of two years (January 2015 to December 2016) for the analysis of various physico-chemical (water temperature, current velocity, conductance, turbidity, pH, dissolved oxygen, total hardness, total alkalinity, nitrate and phosphate) and biological parameters (periphyton). The idea was to understand whole community structure of periphyton and the impact of physio-chemical parameter. A total of 19 periphytic genera belonging to five classes, were found in the Western Nayar River during 2015 and 2016. Periphyton was embodied by five classes, Bacillariophyceae, Chlorophyceae, Cyanophyceae, Ulvophyceae and Zygnematophyceae at all the four investigation sites in the river. During the year 2015, periphyton community of Western Nayar river was represented by 18 genera belonging to five classes, Bacillariophyceae (9 genera), Chlorophyceae (2 genera) Cyanophyceae (3 genera) Ulvophyceae (2 genera) and Zygnematophyceae (2 genera). The mean density varied from 394.5833×103±183.739 at S-1, 674.625×103±293.0523 at S-2, 401.667×103±214.371 at S-3 and 365.042×103±177.343 at S-4. The total density differed significantly (p=0.004) between the four stations during 2015 while it was insignificant (p=0.10) during 2016. Overall it was observed that there was close similarity between winters and lowest in the monsoon in all the station studied during both the year. SIMPER results revealed 20.39% and 14.13% average dissimilarity between the four stations during 2015 and 2016 respectively. Canonical correspondence analysis revealed significant relation between environmental variables and the periphyton taxa. CCA indicated that total alkalinity, DO, water turbidity, nitrate, Current velocity, pH and total hardness were of primary importance and favored the growth and abundance of Cladophora, Spirogyra, Synedra, Phormidium, Spirulina, Stigeocolonium, Amphora and Nitzchia.