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Articles 181 - 210 of 237

Full-Text Articles in Ecology and Evolutionary Biology

Host-Parasite Interactions In An Invasive Songbird, Courtney A.C. Coon Apr 2014

Host-Parasite Interactions In An Invasive Songbird, Courtney A.C. Coon

USF Tampa Graduate Theses and Dissertations

Introduced species are the greatest threat to biodiversity after habitat loss. Understanding the processes that permit organisms to become successful invaders may provide opportunities to prevent or limit their dispersal and establishment and thereby alleviate some of their harmful effects. The goal of my dissertation research has been to investigate whether invasive species have distinctive interactions with parasites, and some of the mechanisms that may underlie that variation. I used one of the world's most successful vertebrate invaders as a case study: the house sparrow (Passer domesticus; Introduction).

Previous research in the house sparrow suggested that loss of …


An Investigation Into The Habitat, Behavior And Opportunistic Feeding Strategies Of The Protected Goliath Grouper (Epinephelus Itajara), Angela Collins Apr 2014

An Investigation Into The Habitat, Behavior And Opportunistic Feeding Strategies Of The Protected Goliath Grouper (Epinephelus Itajara), Angela Collins

USF Tampa Graduate Theses and Dissertations

Groupers (Epinephelidae: Epinephelinae) are apex predators within many reef communities worldwide. Grouper landings contribute significantly to global fisheries, and many populations are suffering from unsustainable levels of exploitation. The large size, site specificity and catchability of most groupers increase susceptibility to fishing pressure, and a large number of grouper species throughout the world are currently overfished. Multiple species are listed as endangered or threatened, and many have suffered local extirpations across their range. Removal of these upper level predators can significantly alter community structure and result in second order effects that may have critical ecological implications. The economic and ecological …


Overwintering And Early Season Amplification Of Eastern Equine Encephalitis Virus In The Southeastern United States, Andrea Bingham Mar 2014

Overwintering And Early Season Amplification Of Eastern Equine Encephalitis Virus In The Southeastern United States, Andrea Bingham

USF Tampa Graduate Theses and Dissertations

Eastern equine encephalitis virus (EEEV) is a highly pathogenic arbovirus that causes severe disease, with a mortality rate of approximately 30-35% in humans and 80-90% in horses. Studies dating back to the 1930's have identified many of the epidemiological and ecological aspects of the virus. However, there are several aspects of EEEV's transmission cycle that remain unclear. In the northeastern states, transmission is seasonal, peaking in the late summer months, while in Florida there is year-round transmission of EEEV. Recent phylogenetic studies have also suggested that Florida may serve as a reservoir for EEEV; the virus may periodically be introduced …


Karenia Brevis Harmful Algal Blooms: Their Role In Structuring The Organismal Community On The West Florida Shelf, Alisha Marie Gray Mar 2014

Karenia Brevis Harmful Algal Blooms: Their Role In Structuring The Organismal Community On The West Florida Shelf, Alisha Marie Gray

USF Tampa Graduate Theses and Dissertations

Karenia brevis dinoflagellate blooms off the west coast of Florida can create devastating effects on marine communities when they release a neurotoxin known as a brevetoxin. These blooms, informally referred to as red tides, can cause massive fish kills, necessitate closures of shellfish fisheries, and can even leave lingering toxins that impact shelf communities long after the bloom has dissipated. As a result, much effort has been put into studying K. brevis bloom initiation and dynamics. However, how K. brevis blooms impact Florida's fisheries is not fully understood because the relationship between K. brevis cell counts and fish mortality is …


Pathways Of Embodiment: Drug Use Among Adolescents In Popay[Aacute]N Colombia, Sarah Louise Fishleder Mar 2014

Pathways Of Embodiment: Drug Use Among Adolescents In Popay[Aacute]N Colombia, Sarah Louise Fishleder

USF Tampa Graduate Theses and Dissertations

This research examines the interrelated biological and cultural factors that determine pathways by which recreational drug use is manifest to addiction in the lives of youth aged 12-18 in Popay[aacute]n, Colombia. It utilizes existing data from mixed methods research conducted between 2004-2005 examining epidemiological risk factors, drug use, perceptions about drugs, and a biological phenomenon of the brain known as incentive salience. Perceptions and experiences related to drugs were gathered using structured methods. MDS and hierarchical plots of drug perceptions are presented in order to demonstrate the power of culture and expectation on perception and choice. Structural equation modeling was …


Epibenthic Mobile Invertebrates Along The Florida Reef Tract: Diversity And Community Structure, Kristin Netchy Mar 2014

Epibenthic Mobile Invertebrates Along The Florida Reef Tract: Diversity And Community Structure, Kristin Netchy

USF Tampa Graduate Theses and Dissertations

Benthic mobile invertebrates are important components of coral-reef diversity and community structure, though, in most cases, their ecological contributions are poorly known. Baseline information on their diversity, prevalence, assemblages, and ecological roles is needed to aid in the conservation of coral-reef habitats. The objectives of this study are to 1) describe diversity and assemblages of epibenthic, mobile invertebrates in shallow water coral-reef communities in Florida, 2) evaluate their ecological roles by reviewing published literature on diet, and 3) measure the degree of linear dependence between mobile invertebrates and scleractinian corals. Underwater surveys were conducted in the summer of 2013 at …


The Conservation Value Of Karst Dolines For Vascular Plants In Woodland Habitats Of Hungary: Refugia And Climate Change, Zoltán Bátori, János Csiky, Tünde Farkas, E. Anna Vojtkó, László Erdős, Dániel Kovács, Tamás Wirth, László Körmöczi, András Vojtkó Jan 2014

The Conservation Value Of Karst Dolines For Vascular Plants In Woodland Habitats Of Hungary: Refugia And Climate Change, Zoltán Bátori, János Csiky, Tünde Farkas, E. Anna Vojtkó, László Erdős, Dániel Kovács, Tamás Wirth, László Körmöczi, András Vojtkó

International Journal of Speleology

Limestone (karst) surfaces in Hungary are rich in dolines, in which many endangered vascular plant species occur. To date, the majority of studies dealing with doline vegetation have focused on the local rather than the landscape level, without using comparative data from other areas. However, in this study we aimed to compare the vegetation pattern and species composition of dolines under different climate regimes of Hungary with regard to regional species pools. The fieldwork was carried out between 2005 and 2012. Twenty dolines were selected in the Mecsek Mountains (southern Hungary) and nine dolines in the Aggtelek Karst area (northern …


National Park Service Cave Ecology Inventory And Monitoring Framework, Gretchen M. Baker, Steven J. Taylor, Shawn Thomas, Rick Olson, Kathy Lavoie, Marie Denn, Steven Thomas, Hazel Barton, Kurt Helf, Rene Ohms, Joel Despain, Jim Kennedy, David Larson Nov 2013

National Park Service Cave Ecology Inventory And Monitoring Framework, Gretchen M. Baker, Steven J. Taylor, Shawn Thomas, Rick Olson, Kathy Lavoie, Marie Denn, Steven Thomas, Hazel Barton, Kurt Helf, Rene Ohms, Joel Despain, Jim Kennedy, David Larson

National Cave and Karst Management Symposium 2013

A team developed the Cave Ecology Inventory and Monitoring Framework for National Park Service (NPS) units. It contains information for NPS cave managers across the United States to determine how to inventory and monitor cave ecology. Due to the wide geographical scope of NPS caves and their many different types, the document does not prescribe exact protocols. Instead, it provides guidance for what types of inventory and monitoring are possible, a framework for deciding how to prioritize inventory and monitoring activities, and references to specific protocols that are already in place at NPS cave parks.

Keywords: cave ecology, cave microbiology, …


Epilithic And Aerophilic Diatoms In The Artificial Environment Of Kungsträdgården Metro Station, Stockholm, Sweden, Lena Norbäck Ivarsson, Magnus Ivarsson, Johannes Lundberg, Therese Sallstedt, Catarina Rydin Sep 2013

Epilithic And Aerophilic Diatoms In The Artificial Environment Of Kungsträdgården Metro Station, Stockholm, Sweden, Lena Norbäck Ivarsson, Magnus Ivarsson, Johannes Lundberg, Therese Sallstedt, Catarina Rydin

International Journal of Speleology

The Kungsträdgården metro station is an artificial and urban subsurface environment illuminated with artificial light. Its ecosystem is almost completely unknown and as a first step to better understand the biology and rock wall habitats the diatom flora was investigated. A total of 12 species were found growing on the rock walls of Kungsträdgården metro station. The results show the diatom flora in Kungsträdgården to be dominated by e.g. Diadesmis contenta, Diadesmis perpusilla, Pinnularia appendiculata, Nitzschia amphibia, Nitzschia sinuata and Diploneis ovalis. One species, Caloneis cf. aerophila, has never been reported from Sweden before. …


Differences In Aquatic Microcrustacean Assemblages Between Temporary And Perennial Springs Of An Alpine Karstic Aquifer, Nataša Mori, Anton Brancelj Sep 2013

Differences In Aquatic Microcrustacean Assemblages Between Temporary And Perennial Springs Of An Alpine Karstic Aquifer, Nataša Mori, Anton Brancelj

International Journal of Speleology

Microcrustacean (Copepoda, Ostracoda) assemblages were investigated at the interface of the vadose and phreatic zones in the alpine karstic aquifer from the Julian Alps in Slovenia (SE Europe). Two temporary and one perennial karstic outlets were sampled by filtering the water several times over 2 years. Concurrently, benthos from the mouth of a perennial spring and from an adjacent spring brook were collected. Altogether 24 microcrustacean species were recorded. The spatial and temporal variation in drift densities and species composition was high indicating complex groundwater hydrological pathways being dependent on precipitation regime. Non-metric Multidimensional Scaling (NMDS) clearly separated drift samples …


Spatial And Temporal Changes In Invertebrate Assemblage Structure From The Entrance To Deep-Cave Zone Of A Temperate Marble Cave, Benjamin W. Tobin, Benjamin T. Hutchins, Benjamin F. Schwartz Aug 2013

Spatial And Temporal Changes In Invertebrate Assemblage Structure From The Entrance To Deep-Cave Zone Of A Temperate Marble Cave, Benjamin W. Tobin, Benjamin T. Hutchins, Benjamin F. Schwartz

International Journal of Speleology

Seasonality in surface weather results in seasonal temperature and humidity changes in caves. Ecological and physiological differences among trogloxenes, troglophiles, and troglobionts result in species-dependent responses to this variability. To investigate these responses, we conducted five biological inventories in a marble cave in the Sierra Nevada Range, California, USA between May and December, 2010. The cave was divided into six quadrats and temperature was continuously logged in each (humidity was logged at the entrance and in the deep cave). With increasing distance from the entrance, temperature changes were increasingly attenuated and lagged relative to surface temperature. Linear regressions were created …


Comparative Microbial Community Composition From Secondary Carbonate (Moonmilk) Deposits: Implications For The Cansiliella Servadeii Cave Hygropetric Food Web, Annette Summers Engel, Maurizio G. Paoletti, Mattia Beggio, Luca Dorigo, Alberto Pamio, Tiziano Gomiero, Claudio Furlan, Mauro Brilli, Angelo Leandro Dreon, Roberto Bertoni, Andrea Squartini Jul 2013

Comparative Microbial Community Composition From Secondary Carbonate (Moonmilk) Deposits: Implications For The Cansiliella Servadeii Cave Hygropetric Food Web, Annette Summers Engel, Maurizio G. Paoletti, Mattia Beggio, Luca Dorigo, Alberto Pamio, Tiziano Gomiero, Claudio Furlan, Mauro Brilli, Angelo Leandro Dreon, Roberto Bertoni, Andrea Squartini

International Journal of Speleology

The microbial diversity of moonmilk, a hydrated calcium carbonate speleothem, was evaluated from two Italian caves to provide context for the food web of highly-specialized troglobitic beetles, Cansiliella spp. (Leptodirinae), with distinctive carbon and nitrogen isotope values indicative of a novel food source. The moonmilk and associated percolating waters had low to no extractable chlorophyll, with an average organic C:N ratio of 9, indicating limited allochthonous input and a significant contribution from microbial biomass. The biomass from moonmilk was estimated to be ~104 micro- and meiofaunal individuals per m2 and ~107 microbial cells/ml. Betaproteobacteria dominated the …


The Economic Impact Of Commensal Rodents On Small Businesses In Manhattan’S Chinatown: Trends And Possible Causes, Anthony Almeida, Robert Corrigan, Ronald Sarno Apr 2013

The Economic Impact Of Commensal Rodents On Small Businesses In Manhattan’S Chinatown: Trends And Possible Causes, Anthony Almeida, Robert Corrigan, Ronald Sarno

Suburban Sustainability

Given the history of well-documented rodent infestations in New York City we were interested in assessing the economic impact of rats and mice on small businesses in The Lower East Side of Manhattan. Via mailed surveys and on-site interviews , we quantified damage to structures, loss of saleable goods and merchandise, the cost of pest-control professionals, and/or self-applied poison/traps. Overall, 16% of business (n = 76) responded to our queries. To those businesses reporting some level of rodent damage, average losses included $513 in merchandise, $726 in pest-control fees, $371 in repair costs to structure, and $125 in do-it-yourself deployment …


The Problem Of Too Many Statistical Tests: Subgroup Analyses In A Study Comparing The Effectiveness Of Online And Live Lectures, David M. Lane Jan 2013

The Problem Of Too Many Statistical Tests: Subgroup Analyses In A Study Comparing The Effectiveness Of Online And Live Lectures, David M. Lane

Numeracy

The more statistical analyses performed in the analysis of research data, the more likely it is that one or more of the conclusions will be in error. Multiple statistical analyses can occur when the sample contains several subgroups and the researchers perform separate analyses for each subgroup. For example, separate analyses may be done for different ethnic groups, different levels of education, and/or for both genders. Media reports of research frequently omit information on the number of subgroup analyses performed thus leaving the reader with insufficient information to assess the validity of the conclusions. This article discusses the problems with …


Physiological And Behavioral Mechanisms Of Range Expansion In The House Sparrow (Passer Domesticus), Andrea Lyn Liebl Jan 2013

Physiological And Behavioral Mechanisms Of Range Expansion In The House Sparrow (Passer Domesticus), Andrea Lyn Liebl

USF Tampa Graduate Theses and Dissertations

Introduced species cause both considerable ecological and economic damage every year. However, not much is known about how certain species are able to establish and spread beyond the site of initial introduction, whereas others do not. Species undergoing range expansion following an introduction may prove to be a valuable resource to invasion biology, but may also be informative in light of species' responses to changing environments (i.e. global climate change). Here, I took advantage of an ongoing range expansion of an introduced vertebrate species. House sparrows (Passer domesticus) were introduced to Mombasa, Kenya in the 1950s and have subsequently expanded …


Understanding Amphibian Decline: The Role Of Pesticides And The Pathogenic Chytrid Fungus On Amphibians And Aquatic Communities, Taegan A. Mcmahon Jan 2013

Understanding Amphibian Decline: The Role Of Pesticides And The Pathogenic Chytrid Fungus On Amphibians And Aquatic Communities, Taegan A. Mcmahon

USF Tampa Graduate Theses and Dissertations

Amphibians are the most threatened taxon on the planet. Declines have been associated with over-exploitation, habitat loss, pollution, and pathogenic diseases, but of these factors, pollution and disease have been relatively under-studied. Here, I investigated: 1) the impacts of commonly used pesticides on aquatic communities, 2) the effect of these pesticides on amphibian susceptibility to the pathogenic chytrid fungus, Batrachochytrium dendrobatidis (Bd), and 3) whether there are non-amphibian hosts of Bd and 4) how to best quantify the survival of Bd through ontogeny of the host.

In my first research chapter, I quantified the effects of environmentally relevant concentrations of …


Evaluating Habitat Vulnerability And Sustainability Of Urban Seagrass Resources To Sea Level Rise, Cynthia A. Meyer Jan 2013

Evaluating Habitat Vulnerability And Sustainability Of Urban Seagrass Resources To Sea Level Rise, Cynthia A. Meyer

USF Tampa Graduate Theses and Dissertations

The seagrass resource provides essential ecosystem functions for many marine species. This research evaluated the vulnerability and sustainability of the seagrass resource in an urbanized area to the effects of sea level rise. The assessment required analysis of information regarding the biogeography of the seagrass resource, and developing a method to model the spatial extent of the suitable habitat for seagrass, and applying the model to predict the implications of simulated sea level rise scenarios on the seagrass resource.

Examining the biogeography of the seagrass resource required the development of a seagrass monitoring and assessment field survey and a comprehensive …


Ecological Interactions Influencing Avicennia Germinans Propagule Dispersal And Seedling Establishment At Mangrove-Saltmarsh Boundaries, Jennifer Mcclain Peterson Jan 2013

Ecological Interactions Influencing Avicennia Germinans Propagule Dispersal And Seedling Establishment At Mangrove-Saltmarsh Boundaries, Jennifer Mcclain Peterson

USF Tampa Graduate Theses and Dissertations

Mangroves and saltmarshes are ecologically important coastal ecosystems; unfortunately, these low-lying coastal ecosystems are vulnerable to global climate change. As sea-levels rise, mangroves are expected to shift their distribution landward towards higher elevation sites that are occupied by other plants, including saltmarsh taxa. Therefore, mangrove recruits at the leading edge of expansion may interact with diverse assemblages of saltmarsh plants, and these interactions could influence the success of mangrove encroachment into higher tidal-elevation areas. The purpose of the research presented here was to investigate empirically the ecological interactions that may influence the recruitment of the black mangrove, Avicennia germinans, …


Agricultural And Domestic Waste Contamination In Chilibre Panama And Potential Low-Cost Best Managament Practices, Christopher Etienne Weekes Jan 2013

Agricultural And Domestic Waste Contamination In Chilibre Panama And Potential Low-Cost Best Managament Practices, Christopher Etienne Weekes

USF Tampa Graduate Theses and Dissertations

Abstract

Sanitation coverage in the Republic of Panama is 5 to 10 percent below the Millennium Development Goals targets set for the country. Population growth, urbanization, unplanned development and waste mismanagement have resulted in improvised trash sites and waste discharges into river systems that are important components of the biologically diverse natural environment of Panama. The study sought to investigate and estimate the burden of waste from domestic and agricultural sources in three regions of the Chilibre corrigimiento (district). It was hypothesized that the water quality and land cover data would reflect that the most populated region in the study …


Gradients In Season, Latitude, And Sea Ice: Their Effect On Metabolism And Stable Isotopic Composition Of Antarctic Micronekton, Erica H. Ombres Jan 2013

Gradients In Season, Latitude, And Sea Ice: Their Effect On Metabolism And Stable Isotopic Composition Of Antarctic Micronekton, Erica H. Ombres

USF Tampa Graduate Theses and Dissertations

Respiration, metabolic enzyme assays, and body composition parameters were measured in the Antarctic krill Euphausia superba during the summer, fall and winter on the Western Antarctic Peninsula (WAP). E. superba of all sizes decrease their metabolism from the summer to the winter. These same parameters were also measured along the WAP during the austral fall 2010. E. superba's enzyme activity indicated that there was a latitudinal gradient to the decline in metabolism along the WAP with the more northerly sites having significantly higher metabolic enzyme activities than the sites to the south.

Carbon (δ13C) and nitrogen (δ15 …


An Investigation Of The Factors Leading To Invasion Success Of Non-Native Plants Using A System Of Native, Introduced Non-Invasive, And Invasive Eugenia Congeners In Florida, Kerry Bohl Jan 2013

An Investigation Of The Factors Leading To Invasion Success Of Non-Native Plants Using A System Of Native, Introduced Non-Invasive, And Invasive Eugenia Congeners In Florida, Kerry Bohl

USF Tampa Graduate Theses and Dissertations

The overwhelming majority of plant species introduced into a new range never become invasive. Consequently, identification of factors allowing the small fraction of successful invaders to naturalize, increase in abundance, and displace resident species continues to be a key area of research in invasion biology. Of the considerable number of hypotheses that have been proposed to resolve why some plant species become noxious pests, the enemy release hypothesis (ERH) is one of the most commonly cited. The ERH maintains that invasive plants succeed in a new range because they are no longer regulated by their coevolved natural enemies, and this …


Ecology Of The Late Neogene Extinctions: Perspectives From The Plio-Pleistocene Of Florida, Shubhabrata Paul Jan 2013

Ecology Of The Late Neogene Extinctions: Perspectives From The Plio-Pleistocene Of Florida, Shubhabrata Paul

USF Tampa Graduate Theses and Dissertations

The ecological impact of past extinction events is one of the central issues in paleobiology. In face of present environmental changes, a better understanding of past extinctions will enable us to identify the magnitude of biodiversity crises and their underlying processes. The Late Neogene was a time of extraordinary climatic reorganization, including Northern Hemisphere glaciation, the rise of the Central American Isthmus, and associated changes in environmental conditions. Therefore, the Late Neogene extinctions of marine molluscs of South Florida present an ideal platform to examine the interaction between environmental changes and biotic response. In the present study, three different aspects …


Associational Resistance And Competition In The Asphondylia - Borrichia - Iva System, Keith Stokes Jan 2013

Associational Resistance And Competition In The Asphondylia - Borrichia - Iva System, Keith Stokes

USF Tampa Graduate Theses and Dissertations

Indirect ecological effects such as associational resistance and resource competition have the potential to affect ecological interactions and influence the structure of ecological communities. Although resource competition is commonly studied, the effects of associational resistance are not as evident if studies are not designed to detect them. Additionally, the relative strengths of different ecological mechanisms ought to be measured in studies, rather than the strength of singular mechanisms. This permits proper attribution of causes and effects in community structure and detection of higher order interactions in a way that naïve reductionism will not.

In a series of experiments, I looked …


Phototactic Behaviour Of Subterranean Copionodontinae Pinna, 1992 Catfishes (Siluriformes, Trichomycteridae) From Chapada Diamantina, Central Bahia, Northeastern Brazil, Bianca Rantin, Maria Elina Bichuette Jan 2013

Phototactic Behaviour Of Subterranean Copionodontinae Pinna, 1992 Catfishes (Siluriformes, Trichomycteridae) From Chapada Diamantina, Central Bahia, Northeastern Brazil, Bianca Rantin, Maria Elina Bichuette

International Journal of Speleology

The phototactic behaviour of three Copionodontinae (Trichomycteridae) catfish species (two troglobites and one epigean) from Chapada Diamantina was studied in order to detect modifications related to isolation in the subterranean environment. Differences in response under different luminosities were detected and, unlike other cavefish, Copionodontinae cave species have shown to be more photophobic than the epigean syntopic to them. The troglobitic Glaphyropoma spinosum is the most photophobic, presenting this behaviour under all light intensities, and more homogeneous regarding morphological characters. It suggests that this population is probably isolated for a longer time in the subterranean environment compared to Copionodon sp. n., …


Fungi Isolated From Niedźwiedzia Cave In Kletno (Lower Silesia, Poland), Rafał Ogórek, Agnieszka Lejman, Krzysztof Matkowski Jan 2013

Fungi Isolated From Niedźwiedzia Cave In Kletno (Lower Silesia, Poland), Rafał Ogórek, Agnieszka Lejman, Krzysztof Matkowski

International Journal of Speleology

Niedźwiedzia Cave is the most beautiful cave in Poland, discovered in a block of Cambrian marbles. It is the most important part of the reserve established in 1977. The cave is located within the Kłodzko Valley, in Śnieżnik Mt. Massif, in Kleśnica Stream Valley and was discovered in 1966 while working in a quarry. The study aimed at first mycological evaluation of the air and the rocks in Niedźwiedzia Cave. Nine species of filamentous fungi and a yeast species were isolated from the air sampled in the cave, whereas from the rocks - nine species of filamentous fungi and two …


Colonization Of Subterranean Habitats By Spiders In Central Europe, Vlastimil Růžička, Petr Šmilauer, Roman Mlejnek Jan 2013

Colonization Of Subterranean Habitats By Spiders In Central Europe, Vlastimil Růžička, Petr Šmilauer, Roman Mlejnek

International Journal of Speleology

Using data from the Czech Republic, we studied the distribution of spiders in soils, crevice systems, scree and caves, i.e. subterranean habitats at depths spanning from 10 cm to 100 m. In total, we found 161 species. The number of species declines with increasing habitat depth, with a major drop in species richness at the depth of 10 meters. Thirteen species exhibit morphological adaptations to life in subterranean habitats. At depths greater than 10 meters, spider assemblages are almost exclusively composed of troglomorphic species. We propose a hypothesis of evolution of troglomorphisms during Quaternary climatic cycles.


Exploring The Sulfide Tolerance Of Ectosymbiotic Niphargus Amphipods From The Frasassi Caves, Central Italy, Jan Bauermeister, Karoline Assig, Sharmishtha Dattagupta Jan 2013

Exploring The Sulfide Tolerance Of Ectosymbiotic Niphargus Amphipods From The Frasassi Caves, Central Italy, Jan Bauermeister, Karoline Assig, Sharmishtha Dattagupta

International Journal of Speleology

Two species of the crustacean amphipod genus Niphargus inhabit the sulfidic groundwaters of the Frasassi caves in central Italy, and both harbor filamentous, sulfide-oxidizing Thiothrix ectosymbionts. As sulfide is toxic to most aerobic organisms, it appeared possible that the ectosymbionts could help their Niphargus hosts with detoxification processes. In this study, mortality due to sulfide was compared between Niphargus individuals with ectosymbionts and individuals whose ectosymbionts had been killed by antibiotic treatment. Both Frasassi-dwelling Niphargus species revealed exceptionally high tolerances to sulfide compared to other amphipod species studied so far. Niphargus individuals without viable ectosymbionts tolerated sulfide levels exceeding those …


The Ecological Role Of Rhizophytic Green Algae In Soft-Bottom Habitats, Laura Bedinger May 2012

The Ecological Role Of Rhizophytic Green Algae In Soft-Bottom Habitats, Laura Bedinger

USF Tampa Graduate Theses and Dissertations

Rhizophytic algae are large, abundant primary producers throughout tropical and subtropical areas worldwide where they grow as an understory in seagrass beds, as well as form mixed or monospecific beds of exclusively rhizophytic algal species. In this dissertation, "rhizophytic algae" refers to coenocytic green algae (Chlorophyta) in the order Bryopsidales that use a net of rhizoids to anchor in unconsolidated sediments. In the development of seagrass beds, rhizophytic algae colonize bare patches and are thought to facilitate seagrass colonization by stabilizing sediments and providing organic matter. However, despite their prominence little is known about many aspects of the ecology of …


Paleobiological Assessment Of Controls Underlying Long-Term Diversity Dynamics, Andrés L. Cárdenas Apr 2012

Paleobiological Assessment Of Controls Underlying Long-Term Diversity Dynamics, Andrés L. Cárdenas

USF Tampa Graduate Theses and Dissertations

Deciphering the factors underlying both long-term patterns of diversity and taxonomic turnover rates (i.e., extinction, and origination) has been one of Paleobiology's major foci for the past three decades. The importance of documenting these components is that they will expand our ability to interpret and model the evolutionary processes underlying those trends, highlight the evolutionary impact of historical events, and contribute to the formulation of robust predictions about the future of global diversity in response to the current anthropologically driven environmental changes. Accordingly, the first part of this study examines the possible occurrence of global marine evolutionary environmental controls into …


Plant Species Richness And Species Area Relationships In A Florida Sandhill, Monica Ruth Downer Mar 2012

Plant Species Richness And Species Area Relationships In A Florida Sandhill, Monica Ruth Downer

USF Tampa Graduate Theses and Dissertations

Pine sandhill are integral pyrogenic communities in the southeastern United States. Though once widespread, habitat destruction, fire suppression and fragmentation have reduced the population to nearly 3%. It is important to learn as much as possible about these unique areas in order to implement best management practices to conserve and restore the existing populations of these communities.

Fire is central to the maintenance of pine sandhill communities and two conceptual hypothesis regarding burn frequency have come to light in maintaining the unique species composition and richness of these areas. The first is the Intermediate Disturbance Hypothesis which suggests that intermediate …