The high altitude, spindle shaped, flat bottomed Kashmir Valley of tectonic origin is a unique natural region, lying within the north-west tip of the oriental stretch with temperate cum sub-mediterranean climate. It is situated in the western Himalayan range between 33° 20’ and 34° 54’N latitudes and 73° 55’ and 75° 35’E longitudes at an average altitude of 1,550 (a.s.l). This beautiful Kashmir Valley is transversed by lone river namely Jhelum (solitary river system of the Kashmir valley and one of the major tributaries of the river Indus). 

The major tributaries of the River Jhelum are Lidder, Sindh, Vishav, Sandran, Erin, Romoush and Rambiara. Among these tributaries, Lidder stream is a major right bank tributary which runs through the beautiful side valley known as “Lidder valley”. Lidder valley, being the great tourist hub in Kashmir and base camp, route to the Amarnath cave is subjected to heavy anthropogenic pressure resulting in the deterioration of entire landscape and streams cape. Lidder stream is at the receiving end of all the wastes produced from the terrestrial land posing great threat to the fragile stream ecosystem. The present work is proposed to study the taxonomical composition of epilithic algae of the stream which can be later taken as base line study to collate it with future studies.

Study area and sites

Lidder stream is about 105 km long having two tributaries- the east Lidder stream and the west Lidder stream. In which the east Lidder stream is formed by snow covered mountain torrents of Panjtarni range and originates from the high altitude glacier fed Sheshnag Lake. On the other side are Kolhoi glaciers flowing from the north towards the northeast and unites with west Lidder tributary at Pahalgam town. The west Lidder stream, originating from Tarsar Lake (glacial fed lake) and other allied glaciers, flows torrentially through Lidderwat and Aru and unites with the east Lidder. After the junction of these torrents, just south of the Pahalgam town, the stream flows in a southwesterly direction on a steep gradient with highest turbulence, finally merges into the River Jhelum at Gur near Khanabal (Anantnag). Thirteen sampling sites (Table 1) were selected on the basis of maximum impact of riparian zone, sediment type, habitat type (riffle, pool and run), impoundment and human habitation on stream system (Figure 1).

Epilithon were collected by scratching 3 to 5 cm² of substratum. The scratched samples were collected in plastic viles containing 30 ml of distal water and later few drops of formalin (4%) or Lugol^’s solution were added to ensure absolute preservation. Then, the samples were transported to laboratory for qualitative and quantitative analysis.

The preserved samples were further diluted with distilled water (1 ml of sample and 9 ml of distilled water). The qualitative and quantitative enumeration of epilithon was done by counting 1 ml of diluted sample in Sedgwick after counting cell (1 ml capacity). The unicellular organisms were counted as unit per centimeter square (unit cm^-2) while in the case of filamentous forms like Chlorophyceae and Cyanophyceae, one filament of specific unit (less than 11 units) was recorded as single cells. A binocular compound microscope was employed for the identification of epilithon with eyepieces of 10 to 40x power. The microscope was calibrated using an ocular micrometer. Epilithon were identified using the standard taxonomic keys of Edmondson (1959), Prescott (1978), Cox (1996) and Biggs (2000).

Diversity of periphyton remained low as compared to lentic systems which might be due to shear stress in the lotic system. In the present study, epilithon component of periphyton makes the major proportion of primary producers. The entire studied stretch of Lidder stream was represented by 144 species of epilithon belonging to Bacillariophyceae, Chlorophyceae, Cyanophyceae, Dinophyceae, Euglenophyceae, Chrysophyceae and Protozoa. Based on the species percentage contribution, Bacillariophyceae was the most dominant class being represented by 104 species (72%), followed by Chlorophyceae with 19 species (13%), Cyanophyceae with 12 species (8%), Euglenophyceae with 4 species (3%) and Phylum Protozoa with 3 species (2%). Classes Chrysophyceae and Dinophyceae of algae contributed 1 species (1%) each (Figure 2). Bacillariophyceae was the most abundant species rich group and represented by some dominant forms like Navicula (Navicula acicularis, Navicula apiculata, Navicula cancelata, Navicula coniformis, Navicula cuspidate, Navicula exilis, Navicula hungarica, Navicula lanceolata, Navicula phylepta, Navicula rhynchocephata, Navicula rostellata, Navicula submrinuscua, Navicula subrhyncocephala, Navicula subtilissima, Navicula sp., Naviculata cinta), Nitzschia (Nitzschia amphibia, Nitzschia angustata, Nitzschia fasciculate, Nitzschia fruslulum, Nitzschia gisela, Nitzschia palea, Nitzschia panduriformis, Nitzschia sigma, Nitzschia uitrea, Nitzschia umbonata, Nitzschia sp.), Cymbella (Cymbella affinis, Cymbella cistula, Cymbella interrupta, Cymbella lanceolata, Cymbella naviculiformis, Cymbella tumida, Cymbella ventricosa, Cymbella vitra, Cymbella sp.) and Gomphonema (Gomphonema fenestrate, Gomphonema germinatum, Gomphonema girdle, Gomphonema natum, Gomphonema subtile, Gomphonema truncatum, Gomphonema sp.). Similarly Amphora, Diatoma, Epithemia and Synedra registered 4 species each while Cocconies, Cyclotella, Fragilaria, Gyrosigma and Surirella listed 3 species each. Achnanthes, Achnanthidium, Ceratonies, Didymosphenia, Eunotia, Hannia, Neidium, Pinnularia, Rhizoclonium, Tabellaria and Liemophora were represented by 2 species each. Cymatopleura, Denticula, Hantzschia, Meriodion, Rhoicosphenia, Stauronies, Enyonema and Placoneis registered only 1 species each and were least represented in the class (Table 2). While in Chlorophyceae, highest number of species was documented by Cosmarium (3 species), Closterium, Euastrum and Ulothrix registered 2 species each. Similarly, taxa like Zygnema, Spirogyra, Hormidium, Hydrodictyon, Microspora, Oedogonium, Pleurotaneium, Chlorohormidium, Cylindrocapsa and Desmidium, were represented by 1 species each. Among blue green algae (Cyanophyceae), genus Spirulina recorded 3 species and Merismopedia registered 2 species while Myxosarcina, Anabaena, Microcystis, Nodularia, Oscillatoria, Rivularia and Nostoc documented only 1 species each.

In the present investigation, high calcium content seems to favor the dominance of Bacillariophyceae (104 species). The presence of indicator diatom species like Navicula, Nitzschia and Cymbella in the study with high calcium concentration clearly indicated that this has been affected by lime quarrying to some extent. Celekli and Kulkoyluoglu (2007) reported that above species could tolerate high calcium concentration in water and they were known as calciphiles or calcium loving organisms. The sub dominance position of green algae in present study might be due to light availability, the most probable reason for the greater proportions of Chlorophyceae may be attributed to the clear water in the studied streams, which provide better light conditions for the growth of group (Allan, 1995), water depth and current velocity (Biggs, 1996; Potapova et al., 2005), light, shading and temperature (Kadhim et al., 2013; Salman et al., 2013), grazing by invertebrate animals (Power, 1990) and sufficient historical time to allow the interactions with these factors to play out. Power (1990) stated that filamentous green algae are natural components of temperate streams and their abundance and seasonal periodicity are influenced by substrate type. Cyanophyceae was dominant during warmer months in Lidder stream as blue-greens has marked tendency to appear in the warm months. Euglenophyceae was sporadic in occurrence at most of the sites while similar pattern was also seen in rest of the groups.

The author(s) have not declared any conflict of interests.