Ecology, Environment and Conservation Paper

ABUNDANCE AND ECOLOGY OF NET AND PHYTOPLANKTON OF A SUBTROPICAL RESERVOIR OF MEGHALAYA (N.E. INDIA)

B.K. Sharma and R.M. Lyngdoh

Abstract

Limnological studies undertaken (November, 1996 - October, 1998) at four sampling stations (1-1V) in Urniam reservoir, Meghalaya indicated 45-71 species of net plankton and low mean abundance (216-267 n/1). Phytoplankton depicted low richness, wider variations in community similarities, mean density between 134-182 n/land comprised between 58.2 - 70.8% of net plankton.The Chlorophyta formed the dominant qualitative and quantitative component, Cyanophyta and Bacillariophyta represented subdominant groups while Dinophyta, Euglenophyta and Chrysophyta recorded poor densities.ANOVA depicted significant variations in net- and phytoplankton abundance at all stations and between months. Phytoplankton registered moderate species diversity, high evenness and low dominance; species diversity and dominance recorded significant variations (vide ANOVA) between months. Multiple regression indicated higher comulative influence of abiotic factors on plankton communities at different sampling stations and the step-wise regression recorded differential impact.