Faunal Diversity and Water Quality of the Beeshazar Lake, Chitwan, Nepal

Abstract

A survey of the Beeshazar Lake was conducted for the abundance and distribution of macro-invertebrates and their relationship between physico-chemical factors at three different sites (Outlet, Clear and Inlet channel). A total of 11 faunal species represented by five groups were recorded during the investigation viz, Oligochaetes, Hirudins, Insects, Gastropods and Bivalves. The overall macroinvertebrates recorded in the study area are comprising dominant groups such as Oligochaetes (34%), Insects (26%), Gastropods (24%), Bivalves (13%) and Hirudins (3%). The faunal density (ind.m 2 ) ranged from 63 to 106, 56 to 76 and 66 to 100 at sites 1-3 respectively, with highest value in June at S 1 .The Shannon diversity and dominance index was ranged from 1.178-1.487 and 0.241-0.336. The species diversity and density were significant positive correlation with temperature, pH, free Co 2 , and hardness but significant negative correlation with dissolved oxygen and alkalinity. The result showed that the variations in physico- chemical factors affects the distribution of the macroinvertebrates.