Coexistence of Competitors in a Stochastic Environment: The Storage Effect

The pre-reproductive, or juvenile stages of an organism, are often the most precarious. These are the stages in the life cycle that are most subject to the vagaries of the environment, while potentially reproductive adults tend to have both higher average survivorship and more predictable survivorship. It follows that recruitment to the adult population is often much more variable than adult survivorship. This difference in variability is increased in some species by a tendency of adults to reduce reproductive effort when conditions are poor thus increasing their own survivorship or enhancing later reproductive success (Murdoch 1966, Goodman 1974, Nichols et al. 1976, Tyler and Dunn 1976).