Title

The effects of Hurricane Andrew on the population dynamics and mating system of the tropical understory shrub Ardisia escallonioides (Myrsinaceae)

Date of Award

1995

Availability

Article

Degree Name

Doctor of Philosophy (Ph.D.)

Department

Biology

First Committee Member

Carol C. Horvitz, Committee Chair

Abstract

The effects of Hurricane Andrew (August 24, 1992) on the tropical understory shrub Ardisia escallonioides (Myrsinaceae) were studied using comparisons of four populations in south Florida along a gradient of hurricane disturbance. Understory light availability in both 1993 and 1994 was very high in three damaged forests and resulted in increased growth and reproduction, but no increase in seed germination and seedling growth. The life-history strategy combines elements typical of both pioneer and shade-tolerant shrubs. Reproductive success was influenced by both increased flowering and hurricane effects on plant-animal interactions. Hurricane disturbance had minimal or positive effects on pollinator assemblage and abundance. Pollination was by generalist halictid bees. There was significant temporal and spatial escape from a specialized seed predating moth, Periploca sp.A matrix model of population dynamics including habitat variation (megamatrix) was constructed. Habitat variation was caused by hurricane disturbance. Frequency of hurricane disturbance was simulated including the historical frequency of hurricanes in south Florida. Matrix models found that population growth rates were greater than 1 for all hurricane frequencies and that population growth rates increased with higher disturbance rates. Elasticity analysis revealed that demographic events in post-hurricane habitats, although rare, contribute the most to long-term population growth at all hurricane frequencies. Stage-specific elasticities for given habitats differ strongly between the habitat-specific models and the megamatrix model.Hand pollination studies revealed that Ardisia escallonioides is self-compatible, autogamous, but not apomictic. Electrophoretic analysis of the mating system of Ardisia escallonioides indicated a mixed-mating system with variable levels of outcrossing among four populations.

Keywords

Biology, Botany; Biology, Ecology

Link to Full Text

http://access.library.miami.edu/login?url=http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9611595