Phenological Pattern of Tree Regeneration in a Model for Forest Species Diversity

A phenological segregation model of forest tree dynamics is studied, which has previously proposed to explain the observed gradient of species diversity along the length of an unfavorable season (e.g., winter or dry months). The assumptions are: the coexistyence of many species in a tropical rain forest is based on lottery competition. With gap formation occurring throughout the year, a season unfavorable for growth causes a peak regeneration opportunity in the beginning of the growing season. The synchronization of the regeneration opportunity jeopardizes the coexistence of many similar species. The model has the globally stable equilibrium, where the curve of regeneration opportunity is best matches by a weighted average of regeneration ability (or niche) curves calculated using the species composition. If the candidate species have the same niche width and different peak dates, the remaining community includes several distinct groups of species with a similar peak regeneration date. If the candidate species differ also in niche width, the equilibrium community includes broad niche species with the peak in the middle of the growing season and narrow niche species with the peak either in the beginning or in the end of the growing season.