Doctor of Philosophy (PhD)
Earth Systems Science
First Advisor's Name
Dr. Hong Liu
First Advisor's Committee Title
Second Advisor's Name
Dr. Suzanne Koptur
Second Advisor's Committee Title
Third Advisor's Name
Dr. Joel T. Heinen
Third Advisor's Committee Title
Fourth Advisor's Name
Dr. James D. Ackerman
Fourth Advisor's Committee Title
Fifth Advisor's Name
Dr. Michael Ross
Fifth Advisor's Committee Title
Cuba, Epiphyte, Everglades, Florida, Microhabitat, Host tree, Melanogromyza miamensis, Markov chain, matrix models, stochastic elasticity, logging
Date of Defense
Population ecology studies are central to species conservation. My dissertation focused on the Florida state-listed endangered orchid, Trichocentrum undulatum at its northern-most range in the Everglades National Park (ENP), Florida and multiple populations throughout its core range in Cuba. Through surveying populations of T. undulatum across this range from 2013-2021, I made a new reporting on the occurrence of a specialized insect herbivore, Melanagromyza miamensis in Cuba (Chapter 1). This flower-crippling herbivore was previously known only in the ENP. With this discovery I assess the intensity and impacts of this herbivore, as well as others on T. undulatum across the populations (Chapter 3). During the orchid population surveys in Cuba, I determined the orchid’s host tree diversity and preference throughout my study sites (Chapter 2). I ranked a list of host trees with two levels of host preference, including a compilation of host diameters and orchid heights. The information provides management recommendations for the species in Florida and can guide the site selection of future species restoration plans. Finally, I conducted repeated demographic censuses documenting individually marked plant survival, growth, and seedling recruitment. These data allowed me to conduct deterministic and stochastic population modeling (Chapter 3). The finite population and stochastic growth rates (λ and λs) show that the ENP population is declining, although experiencing rare and high episodic recruitment. Populations in Cuba experience more stability, which LTREs show is linked to higher rates of adult survival. Alongside the documented herbivory from both M. miamensis and unidentified scale insects, the category 3 storm Hurricane Irma caused increased mortality at the ENP in 2017. Following the hurricane, the ENP site exhibited a surge in short-term survival and growth in the transient analysis that is possibly linked to forest canopy gaps and increased sunlight. Interestingly, herbivory and the hurricane are not the primary reason for long-term population decline at the ENP. The population at ENP is under threat from sea-level rise and the complexities of combating this threat leads to my recommendation of using existing species information to guide restoration activities that are essential for the species survival in the northern- periphery range.
Previously Published In
Chapter 1: Borrero, H., Alvarez, J.C., Prieto, R.O., Coffey, E.D., & Liu, H. (2018). Specialized herbivore on inflorescence stalks of Trichocentrum undulatum (Orchidaceae) by Melanagromyza sp. (Diptera: Agromyzidae) in Cuba. Lankesteriana 18 (3): 189-192.
Chapter 2: Borrero, H., Alvarez, J.C., Prieto, R.O., & Liu, H. (2022) Comparisons of habitat types and host tree species across a threatened Caribbean orchid’s core and edge distribution. Journal of Tropical Ecology.
borrero, haydee, "Population Ecology of a Caribbean Epiphyte Trichocentrum undulatum (orchidaceae): Defining Habitat and the Effects of Herbivory and Hurricanes at Its Peripheral and Core Range" (2022). FIU Electronic Theses and Dissertations. 4933.
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