Theory predicts that when prey can reach a size refuge from predation, prey vulnerability to predation is a function of hatchling size, growth rate, and the handling limitations of its predator, which collectively influence the amount of time prey spend vulnerable. I examined the mechanistic role of prey size for the predator-prey interaction between predatory crayfish (Procambarus fallax) and apple snail prey (Pomacea paludosa and P. maculata) and found that crayfish feeding rates decreased with snail size, such that smaller hatchling P. maculata were more than twenty times more vulnerable than hatchling P. paludosa. Experimental manipulations of productivity increased apple snail growth rates, reducing the effects of predatory crayfish on P. maculata survivorship, but not P. paludosa survivorship. My results indicate that when prey can reach a size refuge from predation, increased system productivity decreases predator limitation of that prey. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

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The Florida manatee (Trichechus manatus latirostris) is native to Florida and the Indian River Lagoon. Harbor Branch Oceanographic Institute (HBOI) is located in Indian River Lagoon and is frequently visited by manatees. The Manatee Project was created in 2009 to document and photograph the manatees visiting HBOI. Analyzing photographs of 146 manatee that visited HBOI showed that a majority of the injuries sustained were caused by boats. 97% of the manatee had at least one propeller injury and 31% of the manatee had at least one skeg injury. Other non-boat related injuries seen in the images included cold stress and entanglement injuries. This study looked at the prevalence of scar by anatomical region, the cause of injury, and compared injury locations between male and female manatees. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

The extant literature on school leadership is bifurcated around the question: Are leaders important, or, is leadership important? Many who think leaders are important, do so because they believe the school’s tone, values, and aspirations start with “a” leader, the principal. However, there are those who believe leadership is not really about a single leader, but about a collective practice among people who work together, with a focus on accomplishing a shared goal. While leadership teams have been studied in a variety of contexts, little research is available on the cumulative effect of a school team’s ability to think collectively to raise student performance. Noteworthy however, is that this study makes the assumption that the sum total of individual agility as measure by instruments designed to assess individual agility equates to an accurate measure of team agility. This study was designed to better understand the relationship between a school leadership team’s cognitive and behavioral agility, school climate, and student achievement in a population of middle schools in Broward County, Florida. Theoretically, the study provides a model in support of the collective leadership approach in moving schools toward improved student achievement. A non-experimental, quantitative research design was utilized and The Strategic Thinking Questionnaire (STQ) and Strategic Leadership Questionnaire (SLQ) were used to assess cognitive and behavioral agility, respectively. Climate data, analyzed as a mediator, was extracted from the schools’ Annual Customer Survey. Student achievement was measured as overall school performance on standardized assessments as part of the State of Florida school accountability system. The STQ and SLQ were administered by way of a survey and descriptive statistics, correlation and mediation analysis were used to analyze data. The research did not point to any statistically significant correlations between school leadership teams’ cognitive and behavior agility as they relate to predicting student achievement; even with school climate acting as a mediator. This may be due in part to the assumption that agility data captured is an accurate reflection of team functioning. The study provides opportunities for additional research on the efficacy of leadership teams in K-12 education. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Shallow water availability coupled with anthropogenic degradation of seagrass beds limits wading bird food resources in dynamic coastal ecosystems. Identifying prey species critical to wading bird reproductive success and the environmental drivers of key prey species abundance is important for understanding how environmental stressors influence prey and change the quality of foraging patches. Little Blue Herons (Egretta caerulea) are reportedly generalists eating insects, crustaceans, and fish; however, the proportions of prey items in the diet may shift spatially and temporally from freshwater to marine systems during breeding and non-breeding periods. I investigated prey selection by Little Blue Herons in Florida at the Great White Heron National Wildlife Refuge and the western Florida Bay, during 2016 and 2017 breeding seasons by investigating prey availability at low-tide locations along mudflats compared to stomach regurgitate samples collected from Little Blue Heron chicks 1 to 4 weeks old. Little Blue Herons selected Gulf toadfish (Opsanus beta) and prawns (Farfantepenaeus spp.) from the estuarine environment, but also consumed terrestrial prey (e.g. tree crabs) suggesting Little Blue Heron foraging habitat is not restricted to tidal flats. Additionally, these results support the characterization of Little Blue Herons as a generalist. After identifying important prey species, I modeled the associations of selected prey species with submerged aquatic vegetation density and abiotic variables to better understand habitat preferences and important habitat characteristics that drive prey density. Models support total seagrass density and algal density as having the greatest effect on prey selected by Little Blue Herons. Prawn density has a strong positive association with seagrass density. Gulf toadfish (Opsanus beta) and prawns (Farfantepenaeus spp.) had strong positive association with algae while pipefish (Syngnathidae) had a strong negative association with algae suggesting algae density in seagrass meadows should be considered when assessing the quality of seagrass meadows for Little Blue Heron prey and habitat suitability. My results varied from previous studies where prawns and gulf toadfish were associated with specific seagrass species. Therefore, some Little Blue Heron prey species in south Florida may not be affected by changes in submerged aquatic vegetation community composition if submerged aquatic vegetation densities remain constant. Studies are needed that clarify the complex interactions between prey and specific habitat metrics to validate the strength of landscape scale drivers of wading bird prey densities in dynamic coastal ecosystems and to determine how these communities will respond to anthropogenic environmental change. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Benthic algal species receive elevated nitrogen (N) and phosphorus (P) availability as anthropogenic activities increase the loading of nutrients into coastal waters. Pelagic species could also be responding to this nutrient enrichment. This study compared the tissue nutrient content and productivity of three benthic and two pelagic species of Sargassum. We hypothesized that the benthic species would have a higher tissue nutrient content and productivity than the pelagic species and the pelagic species would have a higher tissue nutrient content and productivity than historic data. The tissue nutrient content and net productivity of the benthic and pelagic species were not significantly different indicating that the pelagic species are receiving high levels of nutrient availability comparable to that of the benthic species. Pelagic species in the current study exhibited significantly higher N:P ratios and net productivity than the historic data, suggesting a shift from N to P limitation and increased productivity. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Miami Dade College (MDC) is predominantly an associate degree granting institution also authorized to confer baccalaureates. As “democracy’s college”, MDC is the nation’s largest, most diverse community college. In 2011, a comprehensive redesign effort was launched to increase degree completion. This sequential mixed model design study queried teacher education student voices to explore their perceived impact of three high-impact practices (i.e., mandatory orientations, assigned advisors, and Individualized Educational Plans). A survey (n=218) was administered during an initial quantitative phase, confirming that a) students perceived the interventions as the institution intended and b) ethnicity influenced perception. Focus groups (n=27) were conducted during a subsequent qualitative phase, unveiling three overarching findings about how and why perceptions of operational, affective, and academic aspects of the interventions were useful, not useful, or could be enhanced to help them navigate/ “survive” college, make adequate progress, and anticipate graduating, transferring, or entering a career. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection