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The multiple stress gradient hypothesis: expansion of the revised stress gradient hypothesis using a mangrove and salt marsh study system
Title
The multiple stress gradient hypothesis: expansion of the revised stress gradient hypothesis using a mangrove and salt marsh study system.
Creator
Coldren, Glenn A., Proffitt, C. Edward, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Plant interactions (e.g., competition, facilitation) are critical drivers in community development and structure. The Stress Gradient Hypothesis (SGH) provides a predictive framework for how plant species interactions vary inversely across an environmental stress gradient, predicting that facilitation is stronger with increasing levels of stress. The SGH has been supported in numerous ecosystems and across a variety of stress gradients, but recent research has demonstrated contradictory...
Show morePlant interactions (e.g., competition, facilitation) are critical drivers in community development and structure. The Stress Gradient Hypothesis (SGH) provides a predictive framework for how plant species interactions vary inversely across an environmental stress gradient, predicting that facilitation is stronger with increasing levels of stress. The SGH has been supported in numerous ecosystems and across a variety of stress gradients, but recent research has demonstrated contradictory results. These discrepancies have led to SGH revisions that expand its conceptual framework by incorporating additional factors, such as other stressor types and variations in species life history strategies. In this dissertation, I examine a further modification of the SGH by proposing and testing a Multiple Stress Gradient Hypothesis (MSGH) that considers how plant interactions vary along a continuous gradient of two co-occurring stressors using mangrove and salt marsh communities as a case study. In Chapter 1, I outline the predictive framework of a MSGH, by creating a series of predictions of species interactions. The components of the MSGH predict that stressors of similar types (e.g., resource and nonresource) will have similar effects and be additive. On the other hand, varying species life history strategies and life stages will lead to extremes of plant interactions. In Chapter 2, I performed a series of experiments to test the various components of the MSGH. In Chapter 3, I performed a large-scale observational study to test whether multiple co-occurring stressors altered the cumulative effects on plant interactions, and if these stressors should be grouped (e.g., resource and non-resource, abiotic and biotic, etc.) to enhance predictability. From a series of studies conducted herein, I concluded that co-occurring stressors are important factors that control complex species interactions as shown in my MSGH modeling approach. Further, future theories need to incorporate species-specific and stressor specific grouping when modeling how species interactions shape communities.
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Date Issued
2013
PURL
http://purl.flvc.org/fau/fd/FA0004011
Subject Headings
Coastal ecology, Ecophysiology, Mangrove ecology, Plant ecology, Salt marsh ecology
Format
Document (PDF)
Characteristics of mangrove swamps managed for mosquito control in eastern Florida, USA
Title
Characteristics of mangrove swamps managed for mosquito control in eastern Florida, USA.
Creator
Middleton, B, Devlin, D, Proffitt, E, McKee, K, Foster Getini, K
Date Issued
2008-11-19
PURL
http://purl.flvc.org/fau/flvc_fau_islandoraimporter_10.3354_meps07683_1644953107
Format
Document (PDF)
The Role Of Disturbance In The Genotypic And Morphological Diversity Of Halodule Wrightii
Title
The Role Of Disturbance In The Genotypic And Morphological Diversity Of Halodule Wrightii.
Creator
Tiling, Kathryn A., Proffitt, C. Edward, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
Seagrasses are important foundation species in coastal ecosystems. Genetic diversity of seagrasses can influence a number of ecological factors including, but not limited to, disturbance resistance and resilience. Seagrasses in the Indian River Lagoon (IRL), Florida are considered to be highly disturbed due to frequent events, like algal blooms, that impair water quality, reducing available light for seagrass growth. Halodule wrightii is a dominant seagrass throughout the IRL, but its genetic...
Show moreSeagrasses are important foundation species in coastal ecosystems. Genetic diversity of seagrasses can influence a number of ecological factors including, but not limited to, disturbance resistance and resilience. Seagrasses in the Indian River Lagoon (IRL), Florida are considered to be highly disturbed due to frequent events, like algal blooms, that impair water quality, reducing available light for seagrass growth. Halodule wrightii is a dominant seagrass throughout the IRL, but its genetic diversity has only been quantified in a few Gulf of Mexico and Florida Bay populations and little is known about its potential ecological consequences. I quantified the genetic variation of H. wrightii using microsatellite markers in the southern IRL to determine: (i) how disturbance history influenced genetic diversity, (ii) if morphology of clones was, in part, genetically controlled and related to disturbance history, and (iii) if genotypes showed phenotypic plasticity in response to disturbances. In the IRL, H. wrightii populations exhibited moderate genetic diversity that varied with disturbance history. The disturbance history of a population was classified by the variance in the percent occurrence of H. wrightii over a 16-year period. Genotypic richness and clonal diversity of H. wrightii increased with increasing disturbance histories. Other genetic diversity measures (e.g., allelic richness, observed heterozygosity) did not change with disturbance history. These findings suggest that impacts to seagrass coverage over time can change the genotypic composition of populations. When different genotypes of H. wrightii were grown in a common garden, differences in leaf characteristics among genotypes provided evidence that morphological trait variation is, in part, explained by genetic variance. The disturbance history of genotypes did not directly affect morphological traits. However, significant genotype x site (within disturbance history) interactions found greater variation in shoot density and below ground traits of H. wrightii genotypes from sites of intermediate disturbance history. Traits of H. wrightii were shown to be phenotypically plastic. Significant genotype x environment interactions for shoot density and height demonstrated that genotypes responded differently by increasing, decreasing, and not changing sizes in response to light reduction. Genetic diversity of H. wrightii has strong implications for ecological function in coastal communities.
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Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004661, http://purl.flvc.org/fau/fd/FA00004661
Subject Headings
Indian River (Fla. : Lagoon) -- Enviornmental conditions, Indian River Lagoon National Estuary Program (Fla.), Marine ecology -- Florida -- Indian River (Lagoon), Restoration ecology, Seagrasses -- Florida -- Indian River (Lagoon), Seagrasses -- Physiology
Format
Document (PDF)
Mangrove Morphological Change Across an Environmental Gradients: Implications for Competitive Ability in a Changing Climate
Title
Mangrove Morphological Change Across an Environmental Gradients: Implications for Competitive Ability in a Changing Climate.
Creator
Standish, Hilary, Proffitt, C. Edward, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Biological Sciences
Abstract/Description
In Florida, mangroves have responded to climate change by slowly migrating northward into traditional salt marsh habitat. However, little is understood about the relationships among mangrove growth form plasticity and environmental conditions. In addition, the effects of the mangrove northward expansion on pre-existing salt marsh communities are unknown, especially any influences of differences in tree morphology. The size, canopy structure, and root structure of the three mangrove species...
Show moreIn Florida, mangroves have responded to climate change by slowly migrating northward into traditional salt marsh habitat. However, little is understood about the relationships among mangrove growth form plasticity and environmental conditions. In addition, the effects of the mangrove northward expansion on pre-existing salt marsh communities are unknown, especially any influences of differences in tree morphology. The size, canopy structure, and root structure of the three mangrove species Rhizophora mangle, Avicennia germinans, and Laguncularia racemosa were measured at six sites along the east coast of Florida. Structural equation modeling was used to evaluate the multivariate relationships between environmental and biotic variables. Mangrove growth form varied widely with environmental variables. The results of this study suggest that R. mangle expansion into salt marsh may rely on interactions with salt marsh and shading as well as on climatic variables, which has implications for future mangrove expansion northward in Florida.
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Date Issued
2016
PURL
http://purl.flvc.org/fau/fd/FA00004759, http://purl.flvc.org/fau/fd/FA00004759
Subject Headings
Mangrove forests--Florida., Mangrove management., Mangrove ecology., Mangrove conservation., Marine ecosystem management--Florida., Coastal zone management--Florida., Forest ecology., Climatic changes--Florida.
Format
Document (PDF)
INFLUENCES OF WATER QUALITY AND HABITAT RELATIONSHIPS ON THE BURROW DENSITY OF SPHAEROMA TEREBRANS
Title
INFLUENCES OF WATER QUALITY AND HABITAT RELATIONSHIPS ON THE BURROW DENSITY OF SPHAEROMA TEREBRANS.
Creator
Powell, Krystyna, Frazier, Evelyn, Proffitt, C. Edward, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description
Sphaeroma terebrans, is an ecological engineer that can significantly modify the habitat of free-hanging aerial prop roots of Rhizophora mangle. The wood-boring isopod extensively burrows into red mangrove aerial prop roots for habitat and protection from desiccation and access to phytoplankton. However, the burrows created have major consequences on the mangrove habitat and aerial root inhabitants. It has been suggested that sessile species residing in aerial root communities can either...
Show moreSphaeroma terebrans, is an ecological engineer that can significantly modify the habitat of free-hanging aerial prop roots of Rhizophora mangle. The wood-boring isopod extensively burrows into red mangrove aerial prop roots for habitat and protection from desiccation and access to phytoplankton. However, the burrows created have major consequences on the mangrove habitat and aerial root inhabitants. It has been suggested that sessile species residing in aerial root communities can either encourage or discourage colonization by S. terebrans. Abiotic factors can affect the distribution and abundance of mangrove forest and are the same factors which determine the composition and abundance of organisms living on the roots. Surveys indicated that burrowing damage was found predominately in the first 20 cm of the root tip. Exploratory Structural Equation Modeling (SEM) was used to test multivariate hypothesized models looking at habitat relationships with S. terebrans in aerial root communities. Temperature and dissolved oxygen were shown to be important drivers in affecting submerged root length of aerial roots. Ultimately, the indirect effects between these parameters proved to be stronger in influencing the barnacle – isopod association, which causes direct negative effects on submerged root length. Colonial tunicates showed weak effects in masking aerial roots from the damaging barnacle – isopod association. Chlorophyll a was used as a proxy for phytoplankton biomass and proved to be less influential than habitat protection for S. terebrans. Results highlight the need for experimentation in addition to modeling in order to determine the mechanisms influencing aerial root community inhabitants and further effects on the habitat.
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Date Issued
2020
PURL
http://purl.flvc.org/fau/fd/FA00013544
Subject Headings
Sphaeroma, Isopoda, Rhizophora mangle, Red mangrove--Ecology, Prop roots, Habitats
Format
Document (PDF)
THE CRITICAL ROLE OF INTERACTIONS BETWEEN ECOLOGICAL FOUNDATION SPECIES IN STRUCTURING A MANGROVE COMMUNITY
Title
THE CRITICAL ROLE OF INTERACTIONS BETWEEN ECOLOGICAL FOUNDATION SPECIES IN STRUCTURING A MANGROVE COMMUNITY.
Creator
Aquino-Thomas, Jessene, Brooks, W. Randy, Proffitt, C. Edward, Florida Atlantic University, Department of Biological Sciences, Charles E. Schmidt College of Science
Abstract/Description
The main objective of this research was to analyze how well my proposed Foundation Species Interaction model explained the benthic communities found on red mangrove (Rhizophora mangle) prop roots. This research investigated the connections between the primary foundation species (mangroves), the dominant secondary foundations species (oysters, sponges, and barnacles), and the resulting biodiversity in order to understand the temporal and spatial variability of the ecosystems at different...
Show moreThe main objective of this research was to analyze how well my proposed Foundation Species Interaction model explained the benthic communities found on red mangrove (Rhizophora mangle) prop roots. This research investigated the connections between the primary foundation species (mangroves), the dominant secondary foundations species (oysters, sponges, and barnacles), and the resulting biodiversity in order to understand the temporal and spatial variability of the ecosystems at different community levels. Chapter 1 was dedicated to explaining my change in ecological theory, the Foundation Species Interaction model. The interactions included in the model between the foundations species that were examined were the mutualistic (+, +), commensal (+, 0), and parasitic (+, -) interactions. Chapter 2 focused on exploration of the mangrove ecosystem in Southeast Florida and establishing where the secondary foundation species and prop root epibionts where found along the latitudinal gradient. The survey investigated the connections between mangroves, the dominant secondary foundations species (e.g. oysters, sponges, and barnacles), and the resulting biodiversity to understand the temporal and spatial variability of the ecosystems at different community levels. Chapter 3 was dedicated to testing the Foundation Species Interaction model’s ability to predict the biodiversity along the latitudinal gradient of the survey. The difference in mangrove prop root communities were largely explained by where the communities laid along the latitudinal gradient and by secondary foundation species presence. The shift from one foundation species to another had sizable effects on biodiversity. Chapter 4 combined the Foundation Species Interaction model with the established predation hypothesis and tested their abilities to explain biodiversity along the latitudinal gradient. This allowed for shifts in community structure to be examined for top-down and bottom-up influences. Predation effects changed along the latitudinal gradient, as the predation effects changed so did the effects of each of the individual foundation species.
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Date Issued
2020
PURL
http://purl.flvc.org/fau/fd/FA00013561
Subject Headings
Mangrove ecology--Florida, Rhizophora mangle, Red mangrove--Ecology, Biodiversity & ecology
Format
Document (PDF)
FAU Climate Change Initiative Priority Theme: Research, Engineering, and Adaption to a Change Climate
Title
FAU Climate Change Initiative Priority Theme: Research, Engineering, and Adaption to a Change Climate.
Creator
Berry, Leonard, Koch, Marguerite, Center for Environmental Studies, Benscoter, Brian, Comas, Xavier, Devlin, Donna, Fadiman, Maria, Gerstein, E., Herzing, Denise L., Hindle, Tobin, Milton, Sarah L., Oleinik, Anton E., Proffitt, C. Edward, Restrepo, Jorge I., Root, Tara L., Wyneken, Jeanette, Xie, Zhixiao, Zhang, Xing-Hai, Esnard, Ann-Margaret, Mitsova, Diana, Murley, J., Vos, J., Escaleras, Monica, Mehallis, M., Shaw, Eric H., Hardman, Guillermo [John], Lambert, Julie, Thomas, G., Arockiasamy, Madasamy, Bloetscher, Frederick, Carvalho, G., Dhanak, Manhar R., Frisk, George V., Kaisar, Evangelos I., Kalva, Hari, Meeroff, Daniel E., Rodriguez, Jarice, Scarlatos, Panagiotis (Pete) D., Shankar, Ravi, Teegavarapu, Ramesh, Brown, Clifford T., McAfee, Francis, Widener, Patricia, Dalgleish, Fraser R., Hanisak, M. Dennis, McMulloch, S., O'Corry-Crowe, Gregory, Pomponi, Shirley A., Reed, John K., Scarpa, John, Voss, Joshua, Heimlich, Barry N., Alvarez, R., Jolley, J., Edwards, A., Charles E. Schmidt College of Science, Harbor Branch Oceanographic Institute, College of Business, Dorothy F. Schmidt College of Arts and Letters, College of Education, College of Engineering and Computer Science
Date Issued
2010
PURL
http://purl.flvc.org/fau/fd/FA00003457
Format
Citation