Gonsiska, Philip A. .
Heteroblasty, Growth, and Mortality in the Bromeliad Catopsis berteroniana (Schult f.) Mez.
Catopsis berteroniana is an epiphytic, tank-forming bromeliad that exhibits heteroblasty. The life cycle of C. berteroniana can be divided into five stages-seeds, atmospheric seedlings, transitional juveniles, tanks, and reproductive tanks. The atmospheric habit exhibited by seedlings of this and many other tillandsioid tank bromeliads is characterized by a low surface area to volume ratio and narrow, linear leaves with non-imbricate bases. This morphology is considered to be an adaptation for drought tolerance. On the other hand, tank-forming, mature individuals possess strap-shaped leaves and overlapping leaf bases that capture water and debris. Unlike many other tank bromeliads, which are typically shade-adapted, C. berteroniana is a high-light plant and generally occurs in the upper canopy of mangrove swamps and coastal and hardwood hammocks. This study compares the growth and mortality in the non-seed life history stages of C. berteroniana in Florida and the Bahamas. In March of 2004, I tagged individuals of C. berteroniana at one site in Florida and four sites on Andros Island in the Bahamas. Plant size (measured from the rosette base to the tip of the longest leaf) and morphological category (atmospheric seedling, transitional juvenile, tank, reproductive tank) were recorded. I revisited these plants in November of 2004 and recorded plant size, morphological category, and mortality. At this time, I also took hemispherical canopy photos, which were used to determine percent canopy openness, at each of the Bahamian sites. Both morphological class and site had a significant effect on change in plant size (both p < 0.001). Morphological class had a significant effect on survivorship (p < 0.001). The implications of these findings will be discussed.
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1 - Florida International University, Department of Biological Sciences, 11200 Sw 8Th Street, Oe167, Miami, Florida, 33199, USA
Presentation Type: Oral Paper
Location: Salon A - Gov Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 4:00 PM