XVI International Botanical Congess

Froelichia floridana (Amaranthaceae) is an annual herb native to sandy soils in the central and southeastern United States. A disjunct population occurs in the mid-Ohio River valley in southeastern Ohio where it is designated as a state endangered species. Demographic parameters of this population, including soil seed bank, plant survival, and reproductive output, were monitored over a period of two years and used to construct a stage-based transition matrix model. Projections made with this model suggest a steady decline in population size over the next twenty years except in areas where competition from other annual species was reduced. Elasticity analysis indicates the importance of a persistent seed bank to long-term population survival.