DIVERSITY AND DOMINANCE IN PLANKTONIC ROTIFERS

The diversity of planktonic species in a body of water can be estimated in two ways: momentary diversity and long term diversity. The former represents the number capable of coexisting at any one time, and the latter includes a seasonal or other temporal component. The relationship between the two varies mainly with salinity. Dominance is generally inversely related to diversity. In considering the total possible range of dominance for a given number of species the mean values are surprisingly restricted. An abnormally high dominance for a number of species can be an indication of pollution or some other form of environmental stress.