Subspecific taxonomic designations solely based on morphological characters can often lead to erroneous assumptions about the evolutionary history of populations. This study sought to investigate evolutionary questions and conservation implications associated with morphological subspecific designations of island populations. To this end, I focused my attention on the Lower Keys of Florida, a unique chain of islands with well-known geologic history and rich in endemic, endangered subspecies. I employed genetic analyses to evaluate historical variation and contemporary restriction of gene flow between the endangered Lower Keys marsh rabbit (Sylvilagus palustris hefneri) and its sister mainland taxa. A Bayesian phylogeny using 1063 base pairs of the mitochondrial cytochrome b gene did not recover reciprocal monophyly of the three named subspecies, and a 95% statistical parsimony haplotype network showed haplotypes being shared among subspecies. Furthermore, clustering analyses using 10 microsatellite loci identified a break within the Lower Keys, separating the western Lower Keys from the island of Big Pine Key. Surprisingly, Big Pine Key grouped with mainland populations and exhibits higher genetic diversity than the western Lower Keys islands. These unexpected findings suggest either a stepping-stone colonization pattern or recent gene flow between the mainland and Big Pine Key via natural dispersal or undocumented man-mediated transfers. Although these results suggest that subspecies designations within S. palustris are unwarranted, this study supports the designation western Lower Keys population as a discrete unit of conservation with regard to both DPS and ESU criteria. The importance of using several lines of evidence to uncover the evolutionary history of populations and implications for the conservation of island populations are discussed.

Genetic variation was examined in bluehead wrasse, Thalassoma bifasciatum, populations along the Florida Keys. Interpretion of mean heterozygosity (H), percent polymorphic loci per population (P), genetic similarity, and F and G statistics demonstrated a clear division of wrasse populations into "northern" and "southern" groups. Correlation and cluster analyses indicated the six reefs can be grouped in a similar fashion based on genetic and environmental data. The conclusion from this analysis of wrasse populations in the Florida Keys is that substantial population subdivision occurs in response to differing selective pressures created by heterogeneous environments.

Understanding the effect of food abundance on feeding behavior can benefit conservation efforts in many ways, such as to determine whether impacted environments need food supplementation, whether different locations of threatened species contain different food abundances, or whether reintroduction sites are missing key components of a species’ diet. I studied the relationship between feeding behavior and food abundance in the Lower Keys marsh rabbit (Sylvilagus palustris hefneri), an endangered subspecies endemic to the lower Florida Keys. Specifically, my study set out to measure the relative abundance of the primary plants within the natural habitat of the Lower Keys marsh rabbit and estimate the proportion of each of these plants within the rabbit’s diet. With this information, I tested the following hypotheses: first, the Lower Keys marsh rabbit selectively feeds on specific plants; second, that diet does not differ among sites; and third, that diet is not affected by food abundance. Using stable isotope analysis, I determined that two plants were prominent in the rabbit’s diet: a shrub, Borrichia frutescens, and a grass, Spartina spartinae. These two species were prominent in the rabbit’s diet in most patches, even where they were relatively rare, suggesting the rabbits are indeed selectively feeding on these species. In addition, although diet did differ among patches, selective feeding was apparent in all cases. Overall, this study determined that certain food types are important food sources for the federally endangered Lower Keys marsh rabbit and that these rabbits do not feed on plants based on plant abundance. This knowledge can be directly applied to reintroduction and restoration efforts for the Lower Keys marsh rabbit. More generally, the methods used in this study can be applied to other species of concern in order to address questions associated with diet requirements and foraging behavior.

Coral reef degradation has been observed worldwide over the past few decades resulting in significant decreases in coral cover and abundance. However, there has not been a clear framework established to address the crucial need for more sophisticated understanding of the fundamental ecology of corals and their response to environmental stressors. Development of a quantitative approach to coral population ecology that utilizes formal, well established principles of fishery systems science offers a new framework to address these issues. The goal of this dissertation is to establish a quantitative foundation for assessment of coral reefs by developing some essential ecological and population-dynamic components of a size-structured demographic model for coral populations of the Florida Keys coral reef ecosystem. The objective provides the potential to build a quantitative systems science framework for coral populations. A two-stage stratified random sampling design was implemented during two separate survey periods to assess coral populations. Results include precise estimates of adult (> 4 cm) population abundance for several coral species by spatially partitioning abundance and variance into species-relevant reef habitat types. Adult size structure and juvenile abundance were used to evaluate individual coral populations and infer spatial variation in recruitment, growth and survival across habitat types. Partial mortality was characterized in terms of surface area, prevalence, and size-relationships. The development of some ecological and population-dynamic components of a size-structured demographic model for coral populations demonstrates the statistical framework and metrics required for monitoring and assessment of coral reef ecosystems to meet the pressing needs of conservation of coral reef ecosystems specifically in Florida, and throughout the Caribbean and Pacific in general.

by Amber L. Garr. / Thesis (Ph.D.)--Florida Atlantic University, 2012. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2012. Mode of access: World Wide Web. / The presence of heavy metals and other pollutants is detrimental to marine ecosystems. The queen conch, once an important fisheries species in the Florida Keys, has not sufficiently recovered after a 25-year fishery closure. Research has shown high levels of copper and zinc in the gonads and digestive glands of adult conch found in the nearshore waters. Four sites relevant to queen conch larval recruitment were tested in 2010 for the presence of copper and zinc in the water, phytoplankton, sediment, and seagrass epiphytes over seven months. Both metals were detected in all sample types and no seasonal or geographical differences were detected. Surface water concentrations from the field were used to conduct acute and chronic toxicity tests on various ages of queen conch larvae and their phytoplankton food source. When zinc concentrations (0-40 (So(Bg/L) similar to those measured in situ were used, there was no significant impact on conch larval survival although some velar lobe de velopment was impaired. However, field concentrations of copper (0-15 (So(Bg/L), which often surpassed water quality standards, negatively impacted growth, survival, and development of the larvae. Chronic exposure to copper, through the water and food, disrupted the metamorphic success of competent larvae and decreased post-metamorphosis survival. Exposure to copper at later life stages increased mortality, suggesting that heavy metals have a negative effect on larval recruitment in localized areas of the Florida Keys. Structural equation modeling revealed that copper and zinc are moving through the systems differently and are best represented by two different models.

Title from PDF of title page. / Document formatted into pages; contains 112 pages. / Thesis (M.S.)--University of South Florida, 2003. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The Florida Keys Coral Reef Monitoring Project (CRMP) began video transect sampling in 1996 and has continuously monitored 107 Florida Keys stations through 2002. The video was downward pointing and produced images from which planar projection data were calculated to determine percent cover of living benthic organisms. An absence of data assessing correlation between octocoral percent cover and octocoral abundance motivated a study to compare octocoral percent cover with abundance data acquired from the same video transects. The methods employed to extract octocoral abundance data from videotape were validated. Temporal changes in octocoral abundance, size and taxonomic group were determined by examination of video transects of 28 randomly selected stations from 1996, 1998, 1999, and 2002. Size classes were defined as [10cm, 10-40cm, ]40cm (short, medium and tall respectively). / ABSTRACT: Taxonomic groups were Gorgonia ventalina and "other octocorals" in three size classes, and Scleraxonia. An in situ study assessed the accuracy of video-derived counts. Average densities of G. ventalina and Scleraxonia were consistently about one colony/m2. Other octocoral as a group averaged 7-9 colonies/m2. When summarized by height, short and tall averaged about 1-2 colonies/m2, while colonies between 10 and 40 cm in height consistently averaged about 6 colonies/m2. Hurricane Georges, in September 1998, impacted the octocoral assemblage. Abundance declined most at stations near the storm center and stations in shallower water. Storm impact was related to octocoral height. Tall octocorals were removed more frequently than medium, short and encrusting forms. A dramatic increase of short individuals in 2002 is indicative of successful post-hurricane recruitment. By 2002, octocoral abundance had recovered to pre-hurricane levels. / ABSTRACT: This study demonstrated that abundance data can reliably be derived from archived video data, reinforcing the value of standardized video data archives. Octocoral abundance and octocoral percent cover are not strongly correlated because tall individuals disproportionately influence percent cover estimates. Nevertheless, trends in octocoral percent cover are reliable indicators of the trends in octocoral abundance. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

Environmental variation is ubiquitous in natural systems. The genetic and physiological mechanisms governing population-level responses to this variation will impact the process of speciation and the capacity for populations to persist in a changing climate. Until recently, population-level responses to environmental selection remained largely unexplored in marine systems due to the historical assumption that the inherently dispersive nature of most marine taxa would preclude their ability to specialize to local environments. This dissertation represents the first investigation of population-level responses to environmental variation in a Caribbean reef-building coral. This research integrates ecological, physiological, genetic and genomic methods to (1) determine patterns of local adaptation in the Florida Keys, (2) identify stressors driving adaptive responses, (3) distinguish the physiological and genetic mechanisms underlying coral adaptation and (4) assess the potential for future adaptation in the common reef-building coral Porites astreoides. Results demonstrate that corals adapt and/or acclimatize to their local habitat and that this specialization incurs fitness costs. Temperature differences between reefs likely play a selective role in differentiating inshore and offshore coral populations. Genetic and gene expression differences indicate that coral hosts play a substantial role in driving these population-level differences. Inshore corals exhibit greater gene expression plasticity, which may be involved in stabilizing physiological responses to temperature fluctuations experienced at inshore reefs. In addition, naïve juvenile coral recruits from inshore reefs exhibit a growth rate advantage over offshore recruits under elevated temperature treatment, suggesting that thermotolerance differences observed in adult populations could continue to evolve in response to climate change. Taken together these results provide novel insight into the drivers of reef decline in the Florida Keys and the role of the host in coral adaptation capacity. / text

Accurate age estimates for the commercially-important Caribbean spiny lobster, Panulirus argus, would greatly enhance analyses of life history and population dynamics. Previous estimates of their age based on size and growth may be inaccurate because of variable growth in the wild. An established technique for aging crustaceans – histologically-determined lipofuscin content in the nervous system – was used on lobsters reared in the laboratory for up to five years. We verified the presence of lipofuscin in eyestalk neural tissue and described its distribution in cell cluster A of the hemiellipsoid body. Neurolipofuscin content of both sexes increased linearly over the five-year age range, with seasonal oscillations. Growth of these animals, on the other hand, showed sex differences and began to asymptote after three years. Neurolipofuscin concentrations in the two eyestalks from the same animal were similar. These results suggest that the neurolipofuscin technique will be valuable for estimating age of wild-caught P.argus.

Studies of larger symbiont-bearing foraminifers on reefs have revealed their potential as indicators of environmental stress because of their physiological analogies to corals (dependence on algal symbionts for growth and calcification) and relatively short life cycle (a few months to 2 years or more). The purpose of this study is to report distribution patterns and population densities of larger benthic foraminifers (LBF) of the Florida reef tract, specifically reporting abundance data collected from offshore (1995-2000, 2006, 2007) and patch reefs (1996, 2006, 2007). Six years of quarterly data collected from two offshore reefs, Conch (10, 18 and 30m) and Tennessee (8 and 20m), revealed that LBF assemblages primarily varied with habitat depth, in turn reflecting available light and water motion.These assemblages were dominated by Amphistegina gibbosa d'Orbigny and Laevipeneroplis proteus d'Orbigny, which tended to occur together, making up ~40-50% of the assemblages and up to 80% at the Tennessee 20m site. Both overall abundance and evenness of the LBF assemblage structure exhibited the greatest variability at shallower depths. Evenness was inversely related to densities of A. gibbosa, which were typically higher at depth keeping evenness below 0.5. Across the Keys, region (location along the reef tract), reef type (offshore shallow, deep or patch reefs) and symbiont type strongly influenced LBF assemblage dynamics. Upper Keys sites shared the highest degree of inter-region similarity among assemblages (73%), while Biscayne National Park (BNP) and lower Keys sites had the lowest similarity (~60%). This likely reflects the greater variability of habitats found in the latter areas, mainly patch reefs.Chlorophyte-bearers were typically more abundant in shallower turbid waters, with diatom-bearers more abundant at depth. Additionally, I observed a significant two-fold decrease in the proportion of chlorophyte-bearers in the middle Keys likely due to light-limitation by turbid Florida Bay outflow. Finally, data comparisons revealed an inverse relationship between LBF abundances and percent coral cover. Coral cover (2005) was staggeringly low on offshore reefs (5%), but was significantly higher on nearshore patch reefs (12%). Contrastingly, LBF species showed either no difference in abundance between reef types or a greater abundance on offshore reefs.

This study sought to connect two bodies of knowledge--integrative complexity and attribution theory. Integrative complexity is a term that indicates the simplicity vs. complexity of a person's mental frame and perceptual skill. A person who perceives nuance and subtle differences typically scores higher on an integrative complexity measure. Attribution theories are concerned with how individuals perceive causation for various events. The limited research into the linkages between perceived causation for an event and how complexly a person thinks about the domain of that event, coupled with the dearth of attribution research in the natural resource management literature, inspired this research. Florida Keys coral reef users were sent a mail questionnaire between July 2009 and March 2010. Integrative complexity level was determined using an index that was developed for this research. Based on attributional and cognitive complexity literature, it was hypothesized that people who score lower in integrative complexity would exhibit an "external" attribution pattern. Integrative complexity was also proposed to influence: attitude and value extremity; number of perceived problem causes; and use of mediated communication. Finally, it was hypothesized that individuals will assign more blame to other groups than to their own. Six of the study's seven null hypotheses were rejected: 1) a significant relationship was found between integrative complexity level and the number of causes that respondents recorded for the decline of the Florida Keys reef ecosystem, 2) significant differences were observed in attitude extremity according to integrative complexity, 3) significant differences were observed in value orientation according to integrative complexity, 4) significant differences were observed in value extremity according to integrative complexity level, 5) significant differences were observed in mediated communication according to integrative complexity level, and 6) significant differences were observed in blame pattern according to group affiliation. Only one null hypothesis was not rejected: no support was found for a connection between integrative complexity and attribution style. These results indicate support for the integrative complexity index, though work to refine the measure seems in order. Additional recommendations for future research include investigating new approaches to examining the relationship between integrative complexity and attribution style.