Population dynamics of cladocerans in Sunfish Lake, Ontario

Abstract

Investigation of populations of Daphnia rosea, D. retrocurva, and Diaphanosoma leuchtenbergianum in Sunfish Lake, southern Ontario, during 1969 indicated that, in the absence of predation, food supply was the major factor controlling population size and influencing population parameters. Generally with each species, a population peak was preceded by a rise in fecundity, an increase in birth rate, and a fall in death rate. As the carrying capacity of the environment in terms of food was surpassed the population numbers declined, fecundity dropped off, and the death rate rose. A strong negative correlation between fecundity and death rate was observed.