Introduction
Various species diversity indices respond differently to different environmental and behavioral factors of biotic communities and therefore, recent investigations have been directed to species diversity indices. Bhadra river is one of the important perennial rivers of the district Shimoga and it connects the river Tunga in Kudli and flows as Tunga Bhadra river. The knowledge of river phytoplankton in India is fragmentary, though a number of contributions are available (Singh and Srivastava, 1988; Misra et al.,1999; Sridhar et al., 2006). In a water body there usually occur a seasonal qualitative fluctuations in planktonic population in tropical and temperate climates (Jhingran, 1980; Tiwari and Chauhan,
2006). In Bhadra river of tropical region, no such study has been reported so far. In the present communication, an attempt was made to study the phytoplankton diversity index in Bhadra river, Karnataka.