Plant Succession: Life History and Competition

Michael Huston, Thomas Smith
1987 American Naturalist  
The continuing generation of hypotheses concerning plant succession suggests that this phenomenon is still not fully understood. Recent work has clarified the great variety of patterns and mechanisms involved in succession (Drury and Nisbet 1973; Connell and Slatyer 1977; MacMahon 1981; McIntosh 1981) but has not produced a general theory based on underlying processes common to all successions (see Peet and Christensen 1980; Van Hulst 1980; Finegan 1984) . We propose to demonstrate why a
more » ... strate why a variety of models can reproduce the superficial patterns of succession but fail to explain the complex dynamics of plant interactions. Our approach is to review a series of succession models, beginning with an oversimplified example and ending with a process-oriented model based on interactions among individual plants. We argue that an individual-based model can explain the complex variety of successional dynamics that population-based models fail to explain. Individual-based models using a combination of life history and physiological traits offer the possibility of an integrated population, community, and ecosystem approach to understanding natural systems. One of the major implications of this approach is that the structure of correlations among life history and physiological traits constrains the successional patterns commonly found in nature to a small subset of the possible patterns. By succession, we mean a sequential change in the relative abundances of the dominant species in a community (dominance based on biomass). Sequential implies that a once-dominant species or group of species will not become dominant again unless a disturbance or other environmental change intervenes. Thus, we focus on the intervals between disturbances rather than on the effects of the disturbances themselves (see Connell 1978; Huston 1979; P. White 1979) . The changes that interest us occur within a time period of the same order of magnitude as the life span of the longest-lived organisms in the successional sequence. This time scale allows us to avoid non-successional changes resulting from longterm climatic shifts as well as the long-term accumulated influence of physical processes on soil development. Shorter-term microclimatic and soil changes induced by vegetation are inherent features of both primary and secondary succession and may playa critical role in causing succession. These and other changes associated with succession form the focus of the ecosystem-level study of succes-
doi:10.1086/284704 fatcat:62wmops3fveljmtxkk6daxpbwi