Plant Succession: Life History and Competition

An approach based on competition among individual plants is presented as an explanation for species replacements during plant succession. Inverse correlations among life history and physiological traits that confer competitive ability under different environmental conditions are shown to be sufficient to produce successional replacements but not sufficient for understanding the complex variety of successional patterns unless they are applied at the individual level rather than at the population level or higher. With models based on competition among individual plants, various combinations of life history and physiological traits can produce the great variety of population dynamics found in natural successions. The classic successional pattern of species replacement results from a particular structure of correlations among life history and physiological characteristics. Atypical patterns of succession result when this correlation structure is altered. Both primary and secondary succession are modeled as nonequilibrium processes, capable of interacting with disturbances to produce steady-state communities whose properties depend on abiotic conditions, such as temperature and resource levels, and on the type and frequency of disturbances.