ORCID Identifier(s)

0000-0001-7585-7832

Graduation Semester and Year

Summer 2025

Language

English

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Biology

Department

Biology

First Advisor

Luke Frishkoff

Second Advisor

Jeffery Demuth

Third Advisor

Matthew Fujita

Fourth Advisor

Alison Ravenscraft

Fifth Advisor

Matthew Walsh

Abstract

One of the fundamental questions in biology is whether natural conditions lead species and communities toward predictable outcomes. Answering this question requires understanding how traits of individual organisms are connected to species- and community-level patterns. In Chapter 2, I examined how thermal physiology and environmental temperatures interact to determine the distribution patterns of Anolis lizards on the Greater Antilles. I combined lab-measured thermal traits (critical thermal minimum: CTmin, critical thermal maximum: CTmax, thermal preference: Tpref) with occurrence and abundance data from 21 species of Anolis lizards collected from extensive mark-resight surveys of communities across the Caribbean islands of Puerto Rico and Hispaniola. To understand the relationship between physiological limits and distribution limits, I tested how well CTmin and CTmax predict the coldest and warmest climates at which species occur. As expected, both physiological measures were significant predictors of species’ climatic limits, although both relationships had substantial error. Next in my assessment of whether physiological niche breadth (CTmax – CTmin) is predictive of climatic niche breadth, I did not find the expected positive relationship. This finding demonstrates that a species which can tolerate a wide range of temperatures will not necessarily occur over a broad range of climates, suggesting that thermal specialization is scale-dependent. Interestingly, I found that the climatic temperature under which species maximize abundance (Tabmax) was the distribution metric best predicted by anole physiology, although in a counterintuitive manner. Physiological limits were better predictors of Tabmax than Tpref, which suggests that the temperatures that best suit the individual are not indicative of conditions that promote long-term population growth and persistence. In sum, my first chapter shows that physiological responses to temperature are not always linked to distribution patterns in predictable ways, and suggests the influence of other factors in setting range-wide distribution patterns. In Chapter 3, I tested whether adaptive radiations of different organisms exposed to the same ecological opportunity are able to exploit available niche space to the same extent across four islands of different sizes: Puerto Rico, Jamaica, Hispaniola, and Madagascar. I used a combination of terrestrial transects and ground-to-canopy arboreal surveys to compare how amphibians and reptiles use vertical niche space on each island. I found that reptiles consistently fill vertical niche space across islands, whereas amphibians rarely reach the canopy. I also found that near the forest floor, both groups occur in higher densities on smaller islands, but only reptiles follow this same abundance-by-island size relationship in the canopy. My findings ultimately suggest that some axes of ecological opportunity are harder to exploit than others, with differences arising based on unique evolutionary limitations of the clades in question. In Chapter 4, I assessed the relative roles of local conditions and regional processes in predicting species richness and abundance patterns for communities of three taxonomic groups: direct-developing frogs, frogs in general, and lizards. Using a nested study design, I assessed hypotheses about the impacts of regional and historical forces on local diversity patterns across five distinct regional species pools: three islands of the Greater Antilles (Puerto Rico, Jamaica, Hispaniola), southeastern Peru, and Madagascar. I also explored the role that evolutionary convergence plays in dictating community convergence for direct-developing frogs. I found that direct-developing frog communities are broadly convergent in species richness, as local conditions are responsible for more variation than are regional processes. In contrast, abundances are more prone to regional differences across all taxa in this study. Lizards are also convergent in species richness, but only among the islands of the Greater Antilles, indicating that shared evolutionary history can play an important role. I also found very few instances of evolutionary convergence between direct-developing frog species, suggesting that community-level convergence can emerge without widespread convergent evolution among constituent species. My results highlight that at broad biogeographic and evolutionary scales, local conditions are highly predictive of community structure, independent of regional contingencies or convergent evolution.

Keywords

ecology, evolution, adaptive radiation, community ecology, herpetology, thermal biology, thermal physiology, biology

Disciplines

Biodiversity | Evolution | Other Ecology and Evolutionary Biology | Terrestrial and Aquatic Ecology

License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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