species diversity and abundance of odonata in sishaghat of tanahun district, nepal

Odonata are one of the most ancient, well studied and fascinating insect orders considered as bio-indicators of aquatic ecosystems. studies on odonata have been carried out in many parts of nepal, but no specific study has been performed in tanahun. hence, a study was conducted to determine the species diversity and abundance of odonata in the sishaghat of tanahun district, nepal from june to august 2020. a transect survey method was used for data collection. a total of six transects (three in each habitat type: agricultural lands and forest streams), each with a length of 200 m were laid out randomly and each transect was surveyed three times. data were pooled and analyzed with spss. a total of 629 individuals of 26 odonata species from 20 genera and 7 families were recorded. the overall shannon-wiener diversity index was h= 2.25, shannon equitability was e= 0.69 and margalefs’ richness index was r= 3.88. sub-order anisoptera was more diverse (h= 1.94) and more abundant (n= 545) than zygoptera (h= 1.31, n= 84). however, species richness was higher and evenness lower in zygoptera (r= 2.26, e= 0.55) than anisoptera (r= 2.22, e= 0.72). anisoptera comprised 15 species within 10 genera from two families and zygoptera comprised 11 species within seven genera from five families. the family libellulidae represented the highest species richness (r= 1.75). neurothemis fulvia and orthetrum pruinosum were the most abundant species (ra= 23.21 and 21.78 respectively). of the recorded odonata, 25 species are included under the least concern and one under the vulnerable category of the iucn. a higher number of species was found in agricultural lands (nine species); hence, the water bodies around this habitat should be preserved to conserve the odonata.