Development of a macroinvertebrate-based Nepal Lake Biotic Index (NLBI): an applied method for assessing the ecological quality of lakes and reservoirs in Nepal

Abstract: In Nepal, the impairment status of lakes and reservoirs has generally been measured and classified based on nutrient concentrations and physico-chemical parameters, typically with no direct measurement of biological communities. In response to the recent focus on the bioassessment of lakes and reservoirs, the macroinvertebrate-based Nepal Lake Biotic Index (NLBI) has been developed. Benthic samples were collected from reference and impaired lakes during 2006 and 2009 from two ecological zones: Terai-Siwaliks and Mid-Hills. We used a tolerance score based on a ten-point scoring system ranging from very pollution sensitive to very pollution tolerant taxa to calculate the NLBI. In reference to the transformation scale, the calculated NLBI describes the lake water quality as high, good, fair, poor and bad. Candidate metrics of richness measures and tolerance measures discriminated well between the reference and impaired lakes (Mann-Whitney U test, p < 0.01). The relationships between the biological metrics and the environmental variables were also established with the lake water quality class (LWQC). Further, the validation of the NLBI performance was done by assessing nine lakes/reservoirs from both the zones. Thus, the index presented here provides an effective method to measure the ecological condition of lakes and reservoirs in Nepal.

Keywords: freshwater ecosystem; lakes; reservoir; ecological assessment; lake biotic index; hydrology; Nepal.

Reference to this paper should be made as follows: Shah, R.D.T., Shah, D.N. and Nesemann, H. (2011) ‘Development of a macroinvertebrate-based Nepal Lake Biotic Index (NLBI): an applied method for assessing the ecological quality of lakes and reservoirs in Nepal’, Int. J. Hydrology Science and Technology, Vol. 1, Nos. 1/2, pp.125–146.

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The Unsustainability of Human Activity

by Deep Narayan Shah

 

Rivers, lakes, wetlands, and forests are increasingly beleaguered by human activities. However, unsustainability is not a condition of having too little of something, and therefore it becomes unsustainable the more we use it. Rather, unsustainability is an inherent characteristic of human beings' lacks of care or concern for life itself.
Today’s indulgent generation has chosen a pattern of mechanization, technology, and development that overtaxes our planet’s resources in an effort to maintain a modern way of living. Thus, we have unwittingly planted the seeds of unsustainable development..........................

Published in The Epoch Times, a multi-language international newspaper spanning 33 countries in 17 languages.  Read more..

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