Study on physico-chemical features of water in Tarahara Fish Farm, Sunsari, Nepal

Tarahara Fish Farm includes 37 large ponds as a fish super zone. Physicochemical parameters viz., air and water temperature, pH, DO, BOD, CO2, Cl-, TA and TH of these ponds were studied for two years (Nov. 2008 to Oct. 2010). The air temperature had positive and significant correlation with water temperature (r=0.893, P<0.01) but inverse and significant correlation with DO (r = - 0.669 P<0.05) and TH (r = - 0.673, P<0.05). Both air and water temperature showed a decreasing trend during the winter months of November to January and again September to October in both years. Similarly, positive and significant correlation showed by pH with DO (r =0.660, P<0.05) and BOD (r =0.846, P<0.05); by free CO2 with DO (r=0.854, P<0.01), chloride (r=0.648, P<0.05) and TA (r=0.616, P<0.05); by DO with TA (r =0.715, P<0.01) and chloride (r =0.625, P<0.05) and by TH with TA (r= 0.592, P<0.05) but inverse and significant correlation showed by pH with water temperature (r =-0.671, P<0.05); by free CO2 with BOD (r=-0.627, P<0.05) and by DO with BOD (r = -0.810, P <0.01). The water quality parameters were within suitable range for the fish growth and breeding with small fluctuations in different months during the first and second years. Physico-chemical parameters significantly (P<0.01; 0.05) differed between different months. However, no mass mortality of fish was recorded from this site. So, the area selected as fish super zone is fruitful to meet the expected production level of fishes and fish seeds in peripheral areas.

Anthropogenic impacts on Keshalia River, Eastern Nepal

The anthropogenic impact on Keshalia river, especially on fish diversity, is very high. Over fishing with unconventional fishing methods, disposal of domestic and industrial effluents, excess use of pesticides, dumping sites of municipalities, dam construction without fish ladder across the river and mining of sands and gravels are major anthropogenic impacts on the river.

Status of noise pollution in urban area of Dharan Sub- Metropolitan City and Inaruwa Municipality of Sunsari District, Nepal

The environmental noise level measurement in Dharan and Inaruwa cities of eastern Nepal were conducted and compared with the ambient noise standards provided by Government of Nepal. The noise pollution assessment was performed in autumn and winter seasons by the indicator average day time sound pressure level (Ld, during 7.00 to 22.00 hrs) and average night time sound pressure level (Ln, during 22.00 to 7.00 hrs). The Ld and Ln values at the commercial, silence and residential zones of Dharan were 78 to 82 and 72 to 73, 65 to 73 and 60 to 70, 65 to 76 and 62 to 64 dB(A) in autumn and 78 to 79 and 72 to 76, 64 to 71 and 58 to 68, 63 to 74 and 60 to 62 dB(A) in winter, respectively whereas for Inaruwa, measurement were 75 to 77 and 73 to 75, 59 and 57, 67 and 60 dB(A) in autumn and 66 to 70 and 63 to 68, 55 and 53, 65 and 58 dB(A) in winter, respectively. The results showed that noise levels exceeded the standard value at most of the sites.

Estimating the population density of the Himalayan Rangeland weed Swertia ciliata (G. Don) Burtt.: An impact of topography and disturbance

Swertia ciliata (G. Don) Burtt. is one of the most problematic weeds in the Himalayan rangelands. The main objective of this work is to assess the magnitude of S. ciliata invasion and analyze the impact of topographic factors and the disturbances on the distribution and population density. The work was conducted during August and September 2012 in the Tinjure-Milke mountain ridge at Gupha Pokhari, Nepal. The rangeland aspects (east, south and west) were considered the first level factor; and slopes (≤45 degree and ≥45 degree inclination) and the disturbance intensity were the second and third factors, respectively. Line transects made up 4 m2, 74 quadrats were laid down randomly to enumerate the weed population. The average population density of the S. ciliata was 127 plants m-2. The population density was found significantly different by the effects of the disturbances as well as aspects whereas the effect of the two slopes was found insignificant to the population density. A space is left for further research by ecological and edaphic factors. The study reveals that the infestation degree of S. ciliata is at a considerable level in the Himalayan rangeland and needs immediate control measures.

Composition and importance value of tree-families in undisturbed and disturbed moist tropical forest of eastern Nepal

Tropical forest disturbances have reduced the tree species diversity and hereby, the ecosystem services provided by them. Present study was carried out to understand the status of tree-families in terms of their dominance in the undisturbed and disturbed stands of moist tropical forest in eastern Nepal. As per the result, the dominant family in both the forest was Dipterocarpaceae, with family importance value of 53.6 and 53.9 in undisturbed and disturbed stands, respectively. The second dominant family in both forest stands was Rubiaceae.

Water quality and biological diversity of Budhoholi Wetland, Jhapa, East Nepal

The present study deals with the physico-chemical parameters and biological diversity of Budhoholi at Sani-Arjun Municipality -7 Jhapa, from July to October, 2015. The physico-chemical properties of water were within the maximum permissible limit with slight variation in some parameters. The biological diversity was found to be rich. Riparian vegetation consisted of 21 herbs 13 shrubs, 11 trees and 4 climbers, 9 aquatic macrophytes and 21 species of fishes. The overall result of the lake indicated that the lake is not disturbed and is not polluted.

Macrophytes of Rajarani-Dhimal Pokhari Wetland, Churia hills, Eastern Nepal

Growth forms, availability and uses of macrophytes found in Rajarani Dhimal Pokhari wetland, Churia hills, eastern Nepal was carried out in 2016. Altogether, 75 species belonging to 64 genera, 30 families, and 7 growth forms were recorded. Growth form classes were: helophytes and hyperhydates (34.7%)> tenagophytes (16%)> pleustophytes (8%) rosulates, epihydates (2.6%)> vittates (1.4%). Nymphea nauchelii, Rorrippa indica; and Cephalanths tetrandra were new aquatic macrophytes to eastern Terai and Nepal, respectively. Aquatic macrophytes useful to local socioeconomy were: feed for livestock (17 sp), edible as pot herbs and wild fruits (5 sp), medicinal (19 sp), green manure/compost (7 sp), fish poison (2 sp), handicrafts as mats/brooms/basketry (8 sp), breeding genetic stock (2 sp) and religious (3 sp). The key species of the wetland Cephalanhus tetrandra is under threat. of Mikania micrantha-an invasive alien species (IAS).

Flowering plants of Sarkuwa VDC, Baglung, Western Nepal

The study was conducted in Sarkuwa VDC of Baglung district, Western Nepal to explore and document the flowering plants. Altogether 127 species of plants belonging to108 genera and 53 families were collected. Dominant families of the study area are Moraceae with 11 species, Asteraceae with 9 species, Fabaceae and Euphorbiaceae with 8 species, Lamiaceae and Verbenaceae with 5 species and Anacardiceae, Meliaceae, Poaceae with 4 species. Among the 127 species, trees are dominant in species composition attaining 39.37 of the whole floristic value, shrub with 27.55%, herb with 25.19%, and climber with 5.15%, under shrub with 1.57% and finally parasite by attaining 0.78%.

Physico-chemical properties of water and soil of Bhimsen Pokhari Wetland, Jhapa District, Eastern Nepal

The functioning of an aquatic ecosystem and its stability support life forms, depend to a great extent on the physico-chemical characteristics of its water and soil. Physico- chemical properties of water and soil were determined in Bhimsen Pokhari wetland of Jhapa districts, eastern Nepal. Soil samples were collected from six sampling sites and analyzed triplicate for each samples. In all sampling site had sandy loam type of soil texture. The proportion of sand showed a marked increase from middle part to corner but clay decrease from middle to corner of the wetland. The acidic nature of soil increased from corner to middle part of the wetland. Soil organic carbon of wetland was higher in the middle part (2.31%) and lower in the North-west corner (1.72%). The result of water analysis showed that the middle part of wetland was slightly acidic than other sampling sites. From the same sampling sites the dissolved oxygen (5.81 mg L-1), total hardness of water (36 ppm) were found higher than other sampling sites. Dissolved oxygen was negatively correlated with the water temperature and pH but positive correlation with the total hardness of water. In conclusion, the middle part of the wetland may be the suitable site for the growth and development of aquatic flora and fauna as well as microbial activities due to having the higher amount of dissolved oxygen and soil organic matter.

Diatoms of Bagmati River, Kathmandu, Nepal

This paper is an outcome of M.Sc. dissertation work carried out by second author during 2014 in Bagmati River, Kathmandu, Nepal. Diatom samples were collected by scraping stones with the toothbrush, squeezing macrophytes and sucking by dropper from three different sites (Mulkharka, Gokarna, Guheshwori-Pashupatinath) along the river during summer, rainy and winter seasons and studied thoroughly in the Phycology Researh Laboratory, Department of Botany, Post Graduate Campus, Biratnagar. A total 48 diatom taxa belonging to 25 genera and 12 families were enumerated. Among them, 20 diatoms were reported first time from Nepal viz., Fragilaria vaucheriae, Achnanthes inflata, Planothidium lanceolatum, Eunotia botuliformis, Gyrosigma scalproides, Stauroneis smithii, Sellaphora capitata, Neidium ampliatum, Navicula escambia, Pinnularia cf divergens, P. grunowii, Gomphonema acidoclinatum, G. gandhii, G. pseudoaugur, G. rhombicum, Cymbella turgidula, Encyonema hustedtii, E. ventricosum, Epithemia adnata, and Surirella angusta. Further extensive studies are essential to understand more about new and interesting diatoms of this river.