Geometry, heterogeneity and competition in variable environments

The effects of environmental fluctuations on coexistence of competing species can be understood by a new geometric analysis, which shows how a species of low density gains an average growth rate advantage when the environment fluctuates and all species have growth rates of the particular geometric form called subadditive. This low density advantage opposes competitive exclusion. Additive growth rates confer no such low density advantage, while superadditive growth rates promote competitive exclusion. Total population growth is divided into different components, such as may be contributed by different life-history stages, phenotypes, or subpopulations in different microhabitats. A three-factor model aids the conceptual division of population growth into suitable components. There is a discussion by P.J.Grubb. -from Author