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Title: ADVANCES IN FIRE DEBRIS ANALYSIS.
Creator: Williams, Mary, Sigman, Michael, University of Central Florida
Abstract / Description: Fire incidents are a major contributor to the number of deaths and property losses within the United States each year. Fire investigations determine the cause of the fire resulting in an assignment of responsibility. Current methods of fire debris analysis are reviewed including the preservation, extraction, detection and characterization of ignitable liquids from fire debris. Leak rates were calculated for the three most common types of fire debris evidence containers. The consequences of...
Show moreFire incidents are a major contributor to the number of deaths and property losses within the United States each year. Fire investigations determine the cause of the fire resulting in an assignment of responsibility. Current methods of fire debris analysis are reviewed including the preservation, extraction, detection and characterization of ignitable liquids from fire debris. Leak rates were calculated for the three most common types of fire debris evidence containers. The consequences of leaking containers on the recovery and characterization of ignitable liquids were demonstrated. The interactions of hydrocarbons with activated carbon during the extraction of ignitable liquids from the fire debris were studied. An estimation of available adsorption sites on the activated carbon surface area was calculated based on the number of moles of each hydrocarbon onto the activated carbon. Upon saturation of the surface area, hydrocarbons with weaker interactions with the activated carbon were displaced by more strongly interacting hydrocarbons thus resulting in distortion of the chromatographic profiles used in the interpretation of the GC/MS data. The incorporation of an additional sub-sampling step in the separation of ignitable liquids by passive headspace sampling reduces the concentration of ignitable liquid accessible for adsorption on the activated carbon thus avoiding saturation of the activated carbon. A statistical method of covariance mapping with a coincident measurement to compare GC/MS data sets of two ignitable liquids was able to distinguish ignitable liquids of different classes, sub-classes and states of evaporation. In addition, the method was able to distinguish 10 gasoline samples as having originated from different sources with a known statistical certainty. In a blind test, an unknown gasoline sample was correctly identified from the set of 10 gasoline samples without making a Type II error.
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Date Issued: 2007
Identifier: CFE0001642, ucf:47242
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001642

Title: LIFE HISTORY AND REPRODUCTIVE BIOLOGY OF CLITORIA FRAGRANS RELATIVE TO FIRE HISTORY ON THE AVON PARK AIR FORCE RANGE.
Creator: Lewis, Michelle, Stout, I. Jack, University of Central Florida
Abstract / Description: The southeastern coastal plain of the United States is a center of endemism for plants in temperate North America and second only to California among the states. In the southeast, Florida has the largest number of these endemic plants. The largest number of these Florida endemics can be found in the fire maintained scrub and sandhill communities located on sandy ridges in Central Florida. One such endemic is Clitoria fragrans, a rare perennial herb. C. fragrans reproduces via a mixed mating...
Show moreThe southeastern coastal plain of the United States is a center of endemism for plants in temperate North America and second only to California among the states. In the southeast, Florida has the largest number of these endemic plants. The largest number of these Florida endemics can be found in the fire maintained scrub and sandhill communities located on sandy ridges in Central Florida. One such endemic is Clitoria fragrans, a rare perennial herb. C. fragrans reproduces via a mixed mating system. It produces both open, chasmogamous flowers and closed, selfed, cleistogamous flowers. Little else is known about its biology. I monitored populations of C. fragrans from 2003-2005 on the Avon Park Air Force Range. I tracked plant density, finite rate of population increase, plant survivorship and reproduction relative to the time since fire and season of fire. I found that recently burned plots had a higher density of plants than those unburned for over 13 years. Unburned populations decreased in all years of the study. In all three years, the majority of flowers produced by Clitoria fragrans were cleistogamous. The production of chasmogamous flowers appears to be influenced by plant size and potentially fire. Unburned plots had less variation than recently burned plots for all independent variables.
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Date Issued: 2007
Identifier: CFE0001950, ucf:47459
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001950

Title: NATIVE FIRE REGIME AS A REFERENCE FOR ESTABLISHING MANAGEMENT PRACTICES.
Creator: Duncan, Brean, Weishampel, John, University of Central Florida
Abstract / Description: Our understanding of natural fire regimes in human-dominated landscapes is limited. Fire regimes operating in the pyrogenic ecosystems of Florida have been altered by fire suppression and fuel fragmentation. This is especially true of North Merritt Island, Florida, where human impacts have led to an incomplete knowledge of current fire regimes. We know that growing season fires frequently occurred within general return intervals and that many native terrestrial species require fire to remain...
Show moreOur understanding of natural fire regimes in human-dominated landscapes is limited. Fire regimes operating in the pyrogenic ecosystems of Florida have been altered by fire suppression and fuel fragmentation. This is especially true of North Merritt Island, Florida, where human impacts have led to an incomplete knowledge of current fire regimes. We know that growing season fires frequently occurred within general return intervals and that many native terrestrial species require fire to remain viable. A 20-year plus period of fire suppression caused structural and compositional changes to vegetation/fuels that led to catastrophic fires and the decline of native species populations such as the Florida Scrub-Jay. Fire has been reintroduced as a means to reduce fuels and maintain habitat requirements for native species. Scientific studies have documented the effects and benefits of prescribed burning on KSC/MINWR habitat/fuels structure. The necessity for fire to maintain vegetation/fuels structure and composition on the landscape is clear so fire is being applied to the landscape despite our imperfect knowledge of the native fire regime. It is imperative for the survival of many native species that fire managers be able to mimic the results of the native fire regime. Fire regime research is difficult in shrublands, and using dendrochronologic techniques are often not possible in flatwoods communities. I therefore used a process of remote sensing, GIS mapping, and spatial modeling to quantify lightning fire ignition properties, the current managed fire regime, and the natural fire regime. Chapter one develops a new remote sensing technique to accurately map burned areas in Florida scrub and pine flatwoods dominated communities on Kennedy Space Center, Merritt Island National Wildlife Refuge, Canaveral National Seashore, and Cape Canaveral Air Force Station, Florida. At the center of this technique is a newly developed separation index (SI) that was used to evaluate each individual satellite image band for its power to discriminate unburned and burned areas. Burned areas were classified and found to be highly accurate in relation to empirical fire records. This chapter addressed a number of issues relevant to the classification of burned areas including: the effect of geographic extent of remote sensing data on classification, determining the best bands for classification, and cleaning classification results by using GIS masking. It also serves as the first published effort to map fire scars in the Florida scrub and flatwoods vegetative communities of the southeastern U.S. using image processing techniques. Chapter two quantified a managed fire regime on John F. Kennedy Space Center, Florida and surrounding federal properties by mapping all fires between 1983 to 2005 using the image processing technique developed in chapter one, time series satellite imagery, and GIS techniques. The goals were to: (1) determine if an image processing technique designed for individual fire scar mapping could be applied to an image time series for mapping a managed fire regime in a rapid re-growth pyrogenic system; (2) develop a method for labeling mapped fire scar confidence knowing that a formal accuracy analysis was not possible; and (3) compare results of the managed fire regime with regional information on natural fire regimes to look for similarities/differences that might help optimize management for persistence of native fire-dependent species. The area burned by managed fire peaked when the drought index was low and was reduced when the drought index was high. This contrasts with the expectations regarding the natural fire regime of this region. Chapter three quantified the natural lightning ignition regime on Kennedy Space Center, Merritt Island National Wildlife Refuge, Canaveral National Seashore, and Cape Canaveral Air Force Station, Florida. Lightning is the natural ignition source in Florida, substantiating the need for understanding lightning fire incidence. Sixteen years of lightning data (1986-2003, excluding 1987 and 2002 due to missing data) from the NASA Cloud to Ground Lightning Surveillance System and fire ignition records were used to quantify the relationship between lightning incidence and fire ignition. Precipitation influenced the efficiency of lightning ignitions, particularly July precipitation. Negative polarity strikes caused the majority of ignitions. Pine flatwoods was ignited more frequently than expected given equal chance of ignition among landcover types. About half (51%) of detected fires were instantaneous ignitions and the other 49% were delayed an average of two days. Summer lightning ignitions were dominant, especially during July, with only one winter lightning ignition. Chapter four used an existing fire regime model (HFire) to simulate the natural fire regime (prior to European settlement) on Kennedy Space Center, Merritt Island National Wildlife Refuge, Canaveral National Seashore, and Cape Canaveral Air Force Station, Florida. A sensitivity analysis was performed to establish which parameters were most important and the range of variation surrounding empirically derived model information from the same model. A mosaic pattern of small fires dominated this fire regime with extremely large fires occurring during dry La Nina periods. Dead fuel moisture and wind speed had the largest influence on model outcome. The majority of variability was found to be in the largest fires. The research presenter here provides a comprehensive perspective on current and historic fire regimes that may be useful for optimizing land management on Kennedy Space Center, Merritt Island National Wildlife Refuge, Canaveral National Seashore, and Cape Canaveral Air Force Station, Florida and throughout the southeastern United States. Native fire dependent species are suffering from many changes imposed from human alteration. The success of conservation efforts protecting native fire dependent species hinge on my factors. Two of the largest factors are first protecting native habitat and then secondly managing that protected habitat to mimic natural maintenance processes for suitable structure and composition which may favor their demography. This study focuses on developing techniques necessary for producing information that can aid the optimization of fire management on these properties and within the southeastern United States, but may be useful in other fire maintained ecosystems globally.
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Date Issued: 2009
Identifier: CFE0002862, ucf:48051
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002862

Title: Wetland diversity in a disturbance-maintained landscape: Effects of fire and a fire surrogate on aquatic amphibian survival and species depauperateness.
Creator: Klaus, Joyce, Noss, Reed, Quintana-Ascencio, Pedro, Jenkins, David, Dr. L. Katherine Kirkman, University of Central Florida
Abstract / Description: Disturbance is one of the central concepts explaining how diversity arises and is perpetuated in ecological time. A good model system for testing hypotheses related to disturbance is the longleaf pine ecosystem in the southeastern U.S. because in this ecosystem frequent, low-severity fires acts as a disturbance that maintains a unique vegetation structure and high species richness. Vegetation structure influences animal distributions; in fire-dependent ecosystems many animals rely on open...
Show moreDisturbance is one of the central concepts explaining how diversity arises and is perpetuated in ecological time. A good model system for testing hypotheses related to disturbance is the longleaf pine ecosystem in the southeastern U.S. because in this ecosystem frequent, low-severity fires acts as a disturbance that maintains a unique vegetation structure and high species richness. Vegetation structure influences animal distributions; in fire-dependent ecosystems many animals rely on open-structured, fire-maintained vegetation but shrubs and trees encroach into fire-dependent ecosystems where fire has been excluded. Prescribed burning and mechanical removal are commonly used as restoration tools to control encroachment. To better assess and compare the restoration potential of these tools, a more thorough understanding of how they change vegetation structure and habitat suitability for animals is necessary.The southeastern U.S. is a diversity hot-spot for amphibians, many of which require ephemeral wetlands embedded in longleaf pine uplands for the aquatic phase of their life cycle. Amphibian diversity has been declining in recent decades and habitat loss/degradation has been cited as one of the leading causes. Although often overlooked in studies of fire ecology, the ephemeral wetlands required by many amphibians are also fire-dependent habitats that have been negatively impacted by lack of fire. To understand how disturbance interacts with wetland vegetation and aquatic-phase amphibians, three disturbance treatments meant to mimic the effects of natural disturbance on vegetation structure were applied randomly to 28 dry ephemeral wetlands in the Lower Coastal Plain of South Carolina, U.S. The treatments consisted of early growing-season prescribed fire, mechanical vegetation removal (a proposed fire surrogate), and a combination of mechanical removal plus fire; some sites were left untreated for reference. Vegetation structure was quantified and amphibian assemblages were monitored before and after treatments. In addition, one species of amphibian was used in a tadpole survival experiment to examine differences in performance among treatments. Other factors that could be affected by treatments and in turn influence amphibians were measured, including water chemistry, wetland depth, quantity and quality of epilithon, and leaf litter composition.Amphibian survival was lowest, and species depauperateness highest in untreated wetlands. Depauperateness of species whose range was restricted to the range of longleaf pine was lowest in sites that had mechanical treatment plus fire. The mechanical plus fire treatment created the most open vegetation structure with lowest leaf litter accumulation, especially of hardwood litter, conditions correlated with high amphibian survival and diversity. When data from this study was combined with data from a previous study of similar nearby wetlands, a pattern emerged in which one suite of species was absent from recently burned sites, while an entirely different suite of species was absent from long-unburned sites. This evidence suggests that disturbance is related to a shift in amphibian assemblage possibly due to changes in vegetation structure and perhaps wetland ecology in general, from an algal-based system maintained by frequent fire to a detrital-based system that develops in the absence of fire.
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Date Issued: 2013
Identifier: CFE0005015, ucf:49994
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005015

Title: The ecology of central Florida's thief ants (Hymenoptera: Formicidae: Solenopsis).
Creator: Ohyama, Leo, King, Joshua, Jenkins, David, Fedorka, Kenneth, University of Central Florida
Abstract / Description: Thief ants of the genus Solenopsis are a diverse group of ants that are found in ant communities throughout the world. They have long been purported to practice lestobiosis, an interaction between small and larger-bodied ants, where small ants cryptically tunnel into larger-bodied ant nests within the subterranean environment and steal brood or eggs for consumption. Thief ants are extremely small, measuring 1-2 mm in length and many of the species within this group practice a subterranean...
Show moreThief ants of the genus Solenopsis are a diverse group of ants that are found in ant communities throughout the world. They have long been purported to practice lestobiosis, an interaction between small and larger-bodied ants, where small ants cryptically tunnel into larger-bodied ant nests within the subterranean environment and steal brood or eggs for consumption. Thief ants are extremely small, measuring 1-2 mm in length and many of the species within this group practice a subterranean life history, where they live the entirety of their lives exclusively belowground. Due to these key characteristics, the ecology and natural history of this group of ants has remained largely unknown despite their noted high abundance within the southeastern United States, especially in upland ecosystems. The purpose of this thesis is to improve our understanding of the ecology of this enigmatic group, providing a solid foundation for future work on their behavior, biology, and natural history. Therefore, this project first attempts to identify key abiotic environmental variables that potentially drive the diversity and distribution of this group in upland ecosystems. Next a field manipulation experiment was conducted in areas of high thief ant density to determine biotic effects between thief ants and the aboveground ant community. This was done by removing thief ants using belowground toxic baits and monitoring co-occurring ant worker abundances throughout a period of approximately 1 year. We found evidence that thief ants dominate belowground and diversity. Our field experiment also yielded evidence indicating that thief ants exert potential top-down regulation on entire ant communities.
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Date Issued: 2019
Identifier: CFE0007696, ucf:52408
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007696

Title: The Application of Chemometrics to the Detection and Classification of Ignitable Liquids in Fire Debris Using the Total Ion Spectrum.
Creator: Lewis, Jennifer, Sigman, Michael, Campiglia, Andres, Clausen, Christian, University of Central Florida
Abstract / Description: Current methods in ignitable liquid identification and classification from fire debris rely on pattern recognition of ignitable liquids in total ion chromatograms, extracted ion profiles, and target compound comparisons, as described in American Standards for Testing and Materials E1618-10. The total ion spectra method takes advantage of the reproducibility among sample spectra from the same American Society for Testing and Materials class. It is a method that is independent of the...
Show moreCurrent methods in ignitable liquid identification and classification from fire debris rely on pattern recognition of ignitable liquids in total ion chromatograms, extracted ion profiles, and target compound comparisons, as described in American Standards for Testing and Materials E1618-10. The total ion spectra method takes advantage of the reproducibility among sample spectra from the same American Society for Testing and Materials class. It is a method that is independent of the chromatographic conditions that affect retention times of target compounds, thus aiding in the use of computer-based library searching techniques. The total ion spectrum was obtained by summing the ion intensities across all retention times. The total ion spectrum from multiple fire debris samples were combined for target factor analysis. Principal components analysis allowed the dimensions of the data matrix to be reduced prior to target factor analysis, and the number of principal components retained was based on the determination of rank by median absolute deviation. The latent variables were rotated to find new vectors (resultant vectors) that were the best possible match to spectra in a reference library of over 450 ignitable liquid spectra (test factors). The Pearson correlation between target factors and resultant vectors were used to rank the ignitable liquids in the library. Ignitable liquids with the highest correlation represented possible contributions to the sample. Posterior probabilities for the ASTM ignitable liquid classes were calculated based on the probability distribution function of the correlation values. The ASTM ignitable liquid class present in the sample set was identified based on the class with the highest posterior probability value. Tests included computer simulations of artificially generated total ion spectra from a combination of ignitable liquid and substrate spectra, as well as large scale burns in 20'x8'x8' containers complete with furnishings and flooring. Computer simulations were performed for each ASTM ignitable liquid class across a range of parameters. Of the total number of total ion spectra in a data set, the percentage of samples containing an ignitable liquid was varied, as well as the percent of ignitable liquid contribution in a given total ion spectrum. Target factor analysis was them performed on the computer-generated sample set. The correlation values from target factor analysis were used to calculate posterior probabilities for each ASTM ignitable liquid class. Large scale burns were designed to test the detection capabilities of the chemometric approach to ignitable liquid detection under conditions similar to those of a structure fire. Burn conditions were controlled by adjusting the type and volume of ignitable liquid used, the fuel load, ventilation, and the elapsed time of the burn. Samples collected from the large scale burns were analyzed using passive headspace adsorption with activated charcoal strips and carbon disulfide desorption of volatiles for analysis using gas chromatography-mass spectrometry.
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Date Issued: 2011
Identifier: CFE0004477, ucf:49301
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004477

Title: Disturbance-Based Management and Plant Species Change in Massachusetts Sandplain Heathlands over the Past Two Decades.
Creator: Martin, Kirsten, VonHolle, Mary, Quintana-Ascencio, Pedro, Weishampel, John, University of Central Florida
Abstract / Description: Massachusetts sandplain heathlands are habitats of conservation concern, harboring many rare plant species and providing habitat for animals that depend on openlands. These heathlands are threatened by human development, shrub encroachment in the absence of disturbance, and potentially increasing soil nutrient levels. Sandplain heathlands are managed with prescribed fire, in order to maintain their open structure and maintain species diversity. In order to assess how past management was...
Show moreMassachusetts sandplain heathlands are habitats of conservation concern, harboring many rare plant species and providing habitat for animals that depend on openlands. These heathlands are threatened by human development, shrub encroachment in the absence of disturbance, and potentially increasing soil nutrient levels. Sandplain heathlands are managed with prescribed fire, in order to maintain their open structure and maintain species diversity. In order to assess how past management was correlated with species change, I used a data set that spanned twenty years from three different heathlands in Massachusetts. I looked for correlations between management and species change. Correlations between species change and prescribed burning were very site, or microsite, specific, indicating that variables such as vegetation type and edaphic characteristics need to be taken into account before management is applied. Prescribed fire was also associated with an increase in ruderal species in one of the sites studied, indicating that there may be undesirable effects of prescribed fire in this system. Species diversity was negatively associated with shrub encroachment, reinforcing the importance of preventing shrubs from encroaching into these heathlands. I also found evidence that burning has not been a successful technique in preventing shrub encroachment in these sites. Lastly, the nitrophilic species Carex pensylvanica increased in all three sites, indicating that future studies should investigate the possibility that sandplain heathlands are currently experiencing nitrogen deposition beyond their critical loads.
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Date Issued: 2013
Identifier: CFE0004886, ucf:49677
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004886

Title: CHARACTERIZING SPONTANEOUS FIRES IN LANDFILLS.
Creator: Moqbel, Shadi, Reinhart, Debra, University of Central Florida
Abstract / Description: Landfill fires are relatively common incidents that landfill operators encounter which have great impact on landfill structure and the environment. According to a U.S. Fire Administration report in 2001, an average of 8,300 landfill fires occurs each year in the United States, most of them in the spring and summer months. Subsurface spontaneous fires are considered the most dangerous and difficult to detect and extinguish among landfill fires. Few studies have been conducted on spontaneous...
Show moreLandfill fires are relatively common incidents that landfill operators encounter which have great impact on landfill structure and the environment. According to a U.S. Fire Administration report in 2001, an average of 8,300 landfill fires occurs each year in the United States, most of them in the spring and summer months. Subsurface spontaneous fires are considered the most dangerous and difficult to detect and extinguish among landfill fires. Few studies have been conducted on spontaneous fires in landfills. Information regarding the thermal behavior of solid waste is not available nor have measurements been made to evaluate spontaneous ignition of solid waste. The purpose of this research was to provide information concerning the initiation of spontaneous ignition incidents in landfills, and investigate the conditions favoring their occurrence. This study enabled better understanding of the self-heating process and spontaneous combustion in landfills. Effects of parameters critical to landfill operation on spontaneous combustion were determined. Spontaneous combustion occurs when materials are heated beyond the ignition temperature. Temperature rise occurs inside the landfill due to exothermic reactions which cause self-heating of the solid waste. Oxygen introduction leading to biological waste degradation and chemical oxidation is believed to be the main cause of rising solid waste temperatures to the point of ignition. A survey was distributed to landfill operators collecting information regarding spontaneous firs incidents in their landfills. Survey results raised new questions necessitating further study of subsurface fires incidents. Subsurface spontaneous fires were not restricted to any landfill geometry or type of waste (municipal, industrial, commercial, and construction and demolition). Results showed that landfill fires occur in landfills that do and do not recirculate leachate. Although new methods have been developed to detect subsurface fires, landfill operators depend primarily on visual observation of smoke or steam to detect the subsurface fires. Also, survey results indicated that excavating and covering with soil are the most widespread methods for extinguishing subsurface fires. Methane often has been suspected for initiating spontaneous subsurface firs in the landfill. However, combustible mixture of methane and oxygen requires very high temperature to ignite. In this study it was shown that spontaneous fires are initiated by solid materials with lower ignition points. Laboratory tests were conducted evaluating the effect of moisture content, oxygen concentration and leachate on spontaneous ignition of solid waste. A new procedure for testing spontaneous ignition is described based on the crossing-point method. The procedure was used to study the spontaneous combustion of solid waste and determine the auto-ignition temperature of the solid waste components and a synthesized solid waste. Correlations have been established between auto-ignition temperature, specific weight and energy content and between self-heating temperature and specific weight. Correlations indicated that compaction can help avoid spontaneous combustion in the landfill. Dense materials require higher energy to increase in temperature and limit the accessibility of oxygen. In the experimental work, moisture was found to promote both biological and chemical self-heating. Increasing moisture content lowers the solid waste permeability and absorbs more energy as it evaporates. Dissolved solids in leachate were found to promote self-heating and ignition more than distilled water. Varying oxygen concentrations indicated that heat generation occurs due to chemical oxidation even at oxygen concentration as low as 10% by volume. However, at 10% by volume oxygen, solid waste did not exhibit thermal runaway nor flammable combustion. At 0% by volume oxygen, tests results indicated occurrence of self-heating due to slow pyrolysis. A numerical one-dimensional energy model was created to simulate temperature rise in landfill for four different scenarios. Using the results from the laboratory experiment, the model estimated the heat generation in solid waste due to chemical reactions. Results from the scenario simulations indicated that moisture evaporation is the major heat sink in the landfill. The model showed that gas flow has a cooling effect due to increasing amount of evaporated water and can control the temperature inside the landfill. The model showed that a temperature higher than the biological limit can be maintained in the landfill without initiating spontaneous fire.
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Date Issued: 2009
Identifier: CFE0002589, ucf:48275
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002589

Title: SOIL MICROBIAL COMMUNITY DYNAMICS IN FLORIDA SCRUB ECOSYSTEM.
Creator: Albarracín, María, Weishampel, John F., University of Central Florida
Abstract / Description: Pyrogenic ecosystems are maintained by fires which vary in frequency, seasonality, and intensity. Florida oak-saw palmetto scrub ecosystem is characterized by fires occurring at intervals of 10-20 years. Diverse factors as private land acquisition and development has created a patchy distribution of scrub ecosystems and also interrupted the natural fire cycle. The effects of fire over plant regeneration and fauna habitat utilization of the scrub have been well characterized in previous...
Show morePyrogenic ecosystems are maintained by fires which vary in frequency, seasonality, and intensity. Florida oak-saw palmetto scrub ecosystem is characterized by fires occurring at intervals of 10-20 years. Diverse factors as private land acquisition and development has created a patchy distribution of scrub ecosystems and also interrupted the natural fire cycle. The effects of fire over plant regeneration and fauna habitat utilization of the scrub have been well characterized in previous research. In the present paper the objective is to characterize the short- and long-term fire effects on the soil microbial community. Fire effects were studied in a chronosequence, comprising a recently burned scrub during a winter-prescribed fire to scrub where fire did not occur for 40 years. The number of culturable cells was reduced by two orders of magnitude by indirect fire effects and environmental factors, principally hydric stress. However, the duration of fire effects was very short since the microbial community returned to pre-fire numbers and activity by day 47 after fire. Microbial community activity was distinctively related to inoculum density in the soil and litter samples. Soil and litter microbial communities showed differences in metabolic activity. There was no difference in substrate utilization pattern, but there was significant seasonal variation related to the decrease in water content during the month of May. Substrate utilization by litter microbial communities was higher during the month of January compared to soil microbial communities and this relationship was inversed during the month of May probably associated to the more stringent conditions, low water availability, on the litter layer. Seasonal effects outweighed fire effects in this study as this environmental constraint determined the microbial community structure and activity.
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Date Issued: 2005
Identifier: CFE0000472, ucf:46353
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000472

Title: RESPONSES OF THE FLORIDA MOUSE (PODOMYS FLORIDANUS) TO HABITAT MANAGEMENT.
Creator: DePue, Jason, Stout, Jack, University of Central Florida
Abstract / Description: The Florida mouse (Podomys floridanus), a species restricted to the Lake Wales Ridge and the Atlantic Coastal Ridge, is recognized by the Florida Fish and Wildlife Conservation Commission as a species of special concern, highlighting its status as a species that is threatened by habitat loss statewide. Publicly owned lands offer protection for the species, but management is generally focused on protecting biodiversity in general and not a particular species. The response of the Florida mouse...
Show moreThe Florida mouse (Podomys floridanus), a species restricted to the Lake Wales Ridge and the Atlantic Coastal Ridge, is recognized by the Florida Fish and Wildlife Conservation Commission as a species of special concern, highlighting its status as a species that is threatened by habitat loss statewide. Publicly owned lands offer protection for the species, but management is generally focused on protecting biodiversity in general and not a particular species. The response of the Florida mouse to land management practices such as mechanical treatment and prescribed fires is poorly documented. This research examined the population responses of Florida mice on three public lands in central Florida, namely, Bullfrog Creek Mitigation Park in Hillsborough County, Split Oak Mitigation Park in Orange County, and Chuluota Wilderness in Seminole County. Florida mice numbers increased or recovered to pre-burn levels within six months following prescribed burns in 2003 and 2004 on the Bullfrog Creek site. Florida mice dropped in numbers following a fire on the Split Oak site, but were increasing when the study ended. The steady decrease in numbers of mice at the Chuluota Wilderness site remained unaffected by habitat modification. Management of public lands that support Florida mice should continue to utilize prescribed fire to maintain upland habitats. When possible, prescribed fires should be limited to the spring and early summer months and applied to only a portion of the total available area in any year.
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Date Issued: 2005
Identifier: CFE0000774, ucf:46564
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000774

Title: VARIABILITY OF CARBON STOCK IN FLORIDA FLATWOODS ECOSYSTEMS UNDERGOING RESTORATION AND MANAGEMENT.
Creator: Becker, Kathryn, Hinkle, C. Ross, University of Central Florida
Abstract / Description: The global community is struggling with mitigating the effects of widespread habitat loss and degradation; the effects of which are being further magnified in the face of global climate change. Quality natural habitat is becoming increasingly limited and atmospheric carbon levels continue to rise. Therefore, land managers responsible for multiuse management are often faced with the dilemma of managing ecosystems for biodiversity, as well as optimizing ecosystem services such as carbon storage...
Show moreThe global community is struggling with mitigating the effects of widespread habitat loss and degradation; the effects of which are being further magnified in the face of global climate change. Quality natural habitat is becoming increasingly limited and atmospheric carbon levels continue to rise. Therefore, land managers responsible for multiuse management are often faced with the dilemma of managing ecosystems for biodiversity, as well as optimizing ecosystem services such as carbon storage and sequestration. However, some management techniques used to meet these objectives may yield conflicting results, specifically, the management tool of prescribed fire. Fire is crucial in maintaining species composition and structure in many ecosystems, but also results in high carbon emissions. Thus, it is important for land mangers to achieve the most efficient prescribed fire management regime to both preserve plant and animal communities, and optimize carbon storage. A former ranchland at the Disney Wilderness Preserve, Central Florida, USA is being restored to native ecosystems and managed to preserve biodiversity and increase carbon storage. This study quantified the carbon stocks within the aboveground biomass, litter, and top 90 cm of soil in five ecosystems at the Disney Wilderness Preserve, all of which are managed with prescribed fire every two to three years. These carbon stocks were compared in ecosystems in different stages of restoration: bahia grass pasture, pasture in restoration for longleaf pine flatwoods, and restored longleaf pine flatwoods. The carbon stocks were also compared among three restored flatwoods communities: longleaf pine flatwoods, slash pine flatwoods, and scrubby flatwoods. To determine the effects of the current prescribed fire management, carbon stocks were quantified and compared in recently burned areas (burned 4 months prior) and areas burned two to three years prior, in all ecosystems. Soil carbon properties were assessed using 13C isotope analysis. Aboveground biomass and litter carbon stocks were found to increase with higher stage of restoration, and were significantly less in areas with recent fire management. The results of this study did not provide evidence that soil carbon stock was significantly different in different stages of restoration or at different times since fire, but soil carbon stock was found to be significantly different among the flatwoods communities. In un-restored pasture and pasture in restoration sites, the soil was found to be increasingly depleted in 13C with increasing soil depth. This pattern indicated that carbon in the upper, more labile soil carbon pool had been derived from current C4 pasture or native grasses, while carbon in the deeper, more stable carbon pool is a legacy of the historical C3 forest vegetation that existed prior to conversion to pasture. Additionally, a pattern of less depletion in 13C with increasing time since deforestation was noted, indicating an increasing loss of historic forest carbon with increasing pasture age. As the pastures in restoration for longleaf pine flatwoods mature, the isotopic composition of the soil profile in the restored longleaf pine flatwoods may serve as a reference value for the soil profiles of these sites. Overall, the mean carbon stock in the aboveground biomass, litter and top 90 cm of soil in the un-restored pasture was ~13.3 kg C/m2, the carbon stock in the pasture in restoration was ~12.7 kg C/m2, the longleaf pine flatwoods had the highest carbon stock at ~17.7 kg C/m2, the scrubby flatwoods had the smallest carbon stock at ~7.7 kg C/m2, and the slash pine flatwoods had a carbon stock of ~15.8 kg C/m2.
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Date Issued: 2011
Identifier: CFE0003603, ucf:48870
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003603

Title: FACTORS AFFECTING BREEDING TERRITORY SIZE AND PLACEMENT OF THE FLORIDA GRASSHOPPER SPARROW (AMMODRAMUS SAVANNARUM FLORIDANUS).
Creator: Aldredge, Jill, Noss, Reed, University of Central Florida
Abstract / Description: For most taxa, maximizing fitness depends on maintaining access to adequate resources. Territories provide exclusive use of resources for an individual or a family group, thus facilitating successful reproduction. The economic defensibility of a territory depends on the quality, abundance, and distribution of its resources as well as the amount of competition that an individual must endure to maintain exclusive access. The benefits of defense must outweigh the costs for territoriality to be...
Show moreFor most taxa, maximizing fitness depends on maintaining access to adequate resources. Territories provide exclusive use of resources for an individual or a family group, thus facilitating successful reproduction. The economic defensibility of a territory depends on the quality, abundance, and distribution of its resources as well as the amount of competition that an individual must endure to maintain exclusive access. The benefits of defense must outweigh the costs for territoriality to be profitable. Territory owners may benefit from territories with high quality resources, but they also may incur greater costs defending these resources from competitors. In contrast, territories with poor quality resources provide fewer benefits to an owner but also may have fewer competitors vying for those resources. Resource quality may change over time, especially in habitats in which periodic ecological disturbances, such as fire, occur. As a result, the cost-benefit equation of defensibility also changes over time. The Florida Grasshopper Sparrow (Ammodramus savannarum floridanus), an Endangered subspecies, is a habitat specialist endemic to the Florida dry prairie, a pyrogenic ecosystem found only in south-central Florida. As a result A. s. floridanus has evolved with frequent fires and its demography is strongly influenced by the structural habitat characteristics, such as sparse woody vegetation and large amounts of bare ground that occur with frequent fire. The objective of my study was to determine what factors associated with fire (i.e. habitat structure and prey abundance) affected the "decisions" of male A. s. floridanus to defend a territory. I hypothesized that fire and the resources resulting from fire would have an impact on territory size and placement. I predicted that territories in more recently burned habitat would be of higher quality and that sparrows would avoid areas with a longer time since fire. I conducted my study at Kissimmee Prairie Preserve State Park in Okeechobee County, FL. One half of my 100-ha study plot had experienced two growing seasons since the last fire and the remaining half had experienced only a single growing season since fire at the start of my study. I mapped territories of all males within my study plot twice over the breeding season; once during the early season (nest building and incubation) and once during the late season (nestling and fledgling stages). In addition, during each survey I collected arthropods and surveyed vegetation composition within territories and at random, unoccupied points within the study plot. I compared the differences between the habitat characteristics of territories and unoccupied areas, the differences between the territories of the males that occupied the two-year rough and those in the one-year rough, males that abandoned their territories mid-season and those that remained in the study plot, and the seasonal changes in territory characteristics between the early and late season territories of males that persisted. My results indicate that A. s. floridanus selects certain habitat characteristics in which to place territories. Males preferred areas with fewer shrubs and more bare ground, which is consistent with previous studies. Prey biomass did not differ between territories and unoccupied areas. Nonetheless, although the mean mass of individual arthropods was larger in unoccupied areas, the numerical abundance of orthopterans, damselflies, and spiders was significantly higher in territories than in unoccupied areas. Sparrows were more likely to abandon their territories if they occurred in the two-year rough as opposed to the one-year rough. Territories in the two-year rough were significantly larger, had poorer quality habitat, and tended to have less prey than those in the one-year rough. The sparrows that persisted throughout the season significantly increased their territory size in the late season; however, very little spatial shift occurred, suggesting that they merely increased their territory size rather than moved to new sites. Early-season territories in the one-year rough were completely exclusive, but late season territories showed considerable overlap, suggesting lack of defense and a shift toward home ranges as opposed to exclusive territories. The habitat quality in late-season territories decreased (more shrubs, less bare ground) from the early season. Unexpectedly, however, the biomass of prey increased. This increase coincides with an increased demand for prey because sparrows are provisioning young. It seems likely that the costs of defense increase at this time because time and energy spent in defense come at the expense of time spent provisioning young. Because prey increases in the late season, the need to defend exclusive territories may decline.
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Date Issued: 2009
Identifier: CFE0002766, ucf:48135
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002766

Title: DATA-TRUE CHARACTERIZATION OF NEURONAL MODELS.
Creator: Suarez, Jose, Behal, Aman, University of Central Florida
Abstract / Description: In this thesis, a weighted least squares approach is initially presented to estimate the parameters of an adaptive quadratic neuronal model. By casting the discontinuities in the state variables at the spiking instants as an impulse train driving the system dynamics, the neuronal output is represented as a linearly parameterized model that depends on ltered versions of the input current and the output voltage at the cell membrane. A prediction errorbased weighted least squares method is...
Show moreIn this thesis, a weighted least squares approach is initially presented to estimate the parameters of an adaptive quadratic neuronal model. By casting the discontinuities in the state variables at the spiking instants as an impulse train driving the system dynamics, the neuronal output is represented as a linearly parameterized model that depends on ltered versions of the input current and the output voltage at the cell membrane. A prediction errorbased weighted least squares method is formulated for the model. This method allows for rapid estimation of model parameters under a persistently exciting input current injection. Simulation results show the feasibility of this approach to predict multiple neuronal ring patterns. Results of the method using data from a detailed ion-channel based model showed issues that served as the basis for the more robust resonate-and- re model presented. A second method is proposed to overcome some of the issues found in the adaptive quadratic model presented. The original quadratic model is replaced by a linear resonateand- re model -with stochastic threshold- that is both computational efficient and suitable for larger network simulations. The parameter estimation method presented here consists of different stages where the set of parameters is divided in to two. The rst set of parameters is assumed to represent the subthreshold dynamics of the model, and it is estimated using a nonlinear least squares algorithm, while the second set is associated with the threshold and reset parameters as its estimated using maximum likelihood formulations. The validity of the estimation method is then tested using detailed Hodgkin-Huxley model data as well as experimental voltage recordings from rat motoneurons.
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Date Issued: 2011
Identifier: CFE0003917, ucf:48724
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003917

Title: Quantitative Assessment of the effects of Microbial Degradation of a Simple Hydrocarbon Mixture.
Creator: Kindell, Jessica, Sigman, Michael, Bridge, Candice, Campiglia, Andres, University of Central Florida
Abstract / Description: Ignitable liquids consist of either a single organic compound or a complex organic mixture. In regards to fire debris analysis, the analyst is responsible for determining if an ignitable liquid residue is present. However, when extracted from soil-containing fire debris evidence, chemical degradation from microorganisms is observed to result in the loss of compounds based on chemical structure. It can also happen when the evidence container is stored at room temperature before analysis. This...
Show moreIgnitable liquids consist of either a single organic compound or a complex organic mixture. In regards to fire debris analysis, the analyst is responsible for determining if an ignitable liquid residue is present. However, when extracted from soil-containing fire debris evidence, chemical degradation from microorganisms is observed to result in the loss of compounds based on chemical structure. It can also happen when the evidence container is stored at room temperature before analysis. This can present a challenge to the fire debris analyst when identifying and classifying the ignitable liquid residue based on the criteria established by standard test methods. The purpose of this research was to observe the microbial degradation of fourteen compounds, at room temperature over a period of time, for possible by-product formation that could coincide with compounds normally present in an ignitable liquid. Additionally, a quantitative assessment was performed to observe and record the loss rate of compounds in a representative simple mixture. Finally, the loss rate from the simple mixture was compared to commercially available ignitable liquids. Degradation studies were conducted to observe the microbial degradation of a representative compounds (individually and in a simple mixture, both weathered and unweathered) and seven ignitable liquids of different ASTM E1618 classifications. Potting soil was spiked with 20 (&)#181;L of a liquid/compound and was allowed to stand at room temperature for a period of time. The simple mixture was evaporated to 50% and 90% using a steady nitrogen gas flow to compare the degradation process to the unweathered mixture. All samples were extracted and analyzed using passive-headspace concentration and gas chromatography-mass spectrometry.The formation of by-products was not observed when degrading the compounds from the simple mixture individually as seen in other research. The simple mixture, unweathered and 50% weathered, resulted in rapid degradation of their oxygenated compounds. The straight-chained alkanes and toluene were observed to be more susceptible to microbial attack than the highly-substituted aromatics and the branched and cyclic alkanes. The 90% weathered mixture followed the same degradation trend as the unweathered and 50% weathered samples, although it only contained two compounds. The loss rates/half-lives for each simple mixture sample (unweathered, 50% weathered, and 90% weathered) were determined to be approximately 3.5, 3.5, and 0.84 days. The unweathered and 50% weathered sample half-lives were similar due to containing compounds with similar susceptibility to degradation, while the 90% weathered sample contained one compound that was more highly susceptible to degradation. When comparing the 3.5 day half-life to the seven different ASTM class liquids, the isoparaffinic product and the naphthenic-paraffinic product had similar rates of degradation while aromatic solvent and normal alkane classes had the shortest half-lives. When observing the degradation of the gasoline, medium petroleum distillate and the miscellaneous, the constituent compounds were seen to exhibit a range of degradation rates that corresponded to half-lives less than and greater than 3.5 days.
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Date Issued: 2015
Identifier: CFE0005966, ucf:50817
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005966

Title: hydro-thermo-mechanical behavior of concrete at elevated temperatures.
Creator: Al Fadul, Manar, Mackie, Kevin, Makris, Nicos, Chopra, Manoj, Kar, Aravinda, University of Central Florida
Abstract / Description: In the light of recent tragic events, such as, natural disasters, arson and terrorism, studying the thermo mechanical behavior of concrete at elevated temperatures has become of special concern. In addition, the fact that concrete has been widely used as a structural material in many critical applications, such as high rise buildings, pressure vessels, and nuclear plants, enhances the potential risk of exposing concrete to high temperatures. Accordingly, the potential damage to large-scale...
Show moreIn the light of recent tragic events, such as, natural disasters, arson and terrorism, studying the thermo mechanical behavior of concrete at elevated temperatures has become of special concern. In addition, the fact that concrete has been widely used as a structural material in many critical applications, such as high rise buildings, pressure vessels, and nuclear plants, enhances the potential risk of exposing concrete to high temperatures. Accordingly, the potential damage to large-scale structures during the course of the fire, besides the possible loss of human life, emphasizes the necessity to better understand the thermo-structural behavior and failure mechanism of concrete exposed to elevated temperatures. In this study, a one-dimensional model that describes coupled heat and mass transfer phenomena in heated concrete was developed. The mathematical model is based on the fully implicit finite difference scheme. The control volume approach was employed in the formulation of the finite difference equations. The primary variables considered in the analysis are temperature, vapor density, and pore pressure of the gaseous mixture. Several phenomena have been taken into account, such as evaporation, condensation, and dehydration process. Temperature, pressure, and moisture dependent properties of both gaseous and solid phases were also considered. Moreover, the proposed model is capable of predicting pore pressure values with a sufficient accuracy, which could be significantly important for the prediction of spalling and fire resistance of concrete. The two dimensional coupled heat and mass transfer problem was then studied by extending the proposed one dimensional model so that it can be applicable in solving two-dimensional problems. Output from the numerical model showed that the maximum values of temperature, pressure, and moisture content occur in the corner zone of the concrete cross section, in which the pore pressure builds up right next to the moisture pocket towards the center. In addition, the model demonstrates the capability to solve the coupled problem in situations involving non symmetric boundary conditions, in which conducting a one dimensional analysis is of no use. The contour plots of the temperature, pressure, and moisture were also presented.Simulation results clearly indicate the capability of the proposed model to capture the complex behavior of the concrete exposed to elevated temperatures in two dimensional systems and to adequately predict the coupled heat and mass transfer phenomena of the heated concrete over the entire flow domain. In order to predict the structural behavior of reinforced concrete members exposed to elevated temperatures, a three-dimensional fiber beam model was developed in this study to compute the mechanical responses of reinforced concrete structures at elevated temperatures by using the well-known sectional analysis approach. The temperature distributions obtained from the two-dimensional coupled heat and mass transfer analysis were used as an input to the strength analysis. The model also accounts for the various strain components that might generate in concrete and steel due to the effect of high temperatures. The constitutive models that describe the structural behavior of concrete and steel at elevated temperatures were also presented. In order to establish the validity of the proposed fiber model, a sequentially coupled thermo mechanical analysis was implemented, in which the model predictions were compared against measured data from tests with good qualitative agreement. The developed model can be considered as an efficient and powerful tool to promptly assess the structural behavior and the integrity of the structure during emergency situations, such as fire events.
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Date Issued: 2017
Identifier: CFE0006551, ucf:51340
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006551

Title: The Effect of Landscape Variables on Adult Mosquito (Diptera:Culicidae)Diversity and Behavior.
Creator: Debevec, Caitlyn, Jenkins, David, King, Joshua, Rothermel, Betsie, Boughton, Raoul, University of Central Florida
Abstract / Description: Diseases vectored by mosquitoes cause millions of deaths each year. In modern times Florida's disease risk has been reduced due to efforts to lessen the prevalence of mosquitoes through habitat modification of non-adults. With emerging diseases (i.e. Dengue and Chikunguya) encroaching into Florida from the Caribbean, this traditional approach may not be enough. Alternatively, we can better understand the ecology of how disease works in an ecosystem. One possible way is through the Dilution...
Show moreDiseases vectored by mosquitoes cause millions of deaths each year. In modern times Florida's disease risk has been reduced due to efforts to lessen the prevalence of mosquitoes through habitat modification of non-adults. With emerging diseases (i.e. Dengue and Chikunguya) encroaching into Florida from the Caribbean, this traditional approach may not be enough. Alternatively, we can better understand the ecology of how disease works in an ecosystem. One possible way is through the Dilution Effect, which states that the more species that are in a system the lower the chance for zoonosis. This project models mosquito diversity across regions, land use, and vegetation height in South-Central Florida, for the purpose of identifying predictors that indicate a higher disease risk using information theory (AICc). The plains and coastal regions as well as the developed areas have a relatively higher risk of disease. Florida is a fire maintained habitat, but has been fire suppressed for the last century. Archbold Biological Station (ABS) has used prescribed fires since the early 1980s to try and restore a more natural system. This has created a mosaic of different fire histories. Fire affects the structures that mosquitoes rest under during the day (they are vulnerable to desiccation during the day and hide in darker/shady places), therefore there is a high likelihood that fire will have some effect on mosquito assemblages. This project used model selection to determine the most plausible set of predictors that describe the effect of fire on mosquito assemblages at ABS, using information theory (AICc). In general, time of season accounted for the largest proportion of the variation in the data and TSF had negligible effect on adult mosquito assemblages measured as abundance, speices richness, and Jost D.
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Date Issued: 2015
Identifier: CFE0005780, ucf:50063
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005780

Title: A Multi-Species Single-LED Hazardous Gas Sensor for Commercial Space Applications.
Creator: Parupalli, Akshita, Vasu Sumathi, Subith, Ahmed, Kareem, Chow, Louis, University of Central Florida
Abstract / Description: In the interest of furthering both commercial and government-funded opportunities for deep space exploration, the safety of life and equipment onboard must be absolutely certain. In this regard, the presence of any hazardous gases or combustion events onboard space vehicles must be quickly characterized and detected. Several hazardous gases of interest have absorption features in the mid-infrared range and can be detected with an infrared light source, via the principles of absorption...
Show moreIn the interest of furthering both commercial and government-funded opportunities for deep space exploration, the safety of life and equipment onboard must be absolutely certain. In this regard, the presence of any hazardous gases or combustion events onboard space vehicles must be quickly characterized and detected. Several hazardous gases of interest have absorption features in the mid-infrared range and can be detected with an infrared light source, via the principles of absorption spectroscopy. A non-dispersive infrared (NDIR) sensor that follows these principles has been developed to utilize light-emitting diodes (LEDs) for gas detection and quantification. LEDs contain a particular advantage in this situation because they have low power requirements, are robust and easily adaptable, and they are cheaper than existing laser-based systems. The design has successfully performed several laboratory, environmental chamber, and high-altitude balloon flight tests. The main purpose of these various tests was to place the sensor in challenging environments, examine the effects on sensor performance, and adjust accordingly.The current sensor design utilizes a single 4.2?m LED and a rotating diffraction grating to detect both carbon dioxide (CO2) and nitrous oxide (N2O) within a single scan. These measurements were further validated using two distributed feedback quantum cascade lasers (QCL) centered at 4.25?m and 4.58?m. The sensor collected data on a wavelength range of 4117nm to 4592nm. Mixtures containing the concentrations of the two species of interest varying from 0.2% to 0.8% were analyzed. The integrated absorbance data was calculated for each species and compared with theoretical predictions. The results show that the data follows the expected behavior and correlates better at lower concentrations. Subsequent work on this sensor will focus on increasing the quantity of identifiable gases and on further testing in hazardous environments.
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Date Issued: 2019
Identifier: CFE0007898, ucf:52752
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007898

Title: SPECIES COMPOSITION AND SPATIOTEMPORAL PATTERN OF THE SEED BANK AND VEGETATION IN NATIVE AND DEGRADED FLORIDA ROSEMARY SCRUB.
Creator: Navarra, Jennifer, Quintana-Ascencio, Pedro, University of Central Florida
Abstract / Description: The soil seed bank plays a dynamic role in the regeneration of plant communities after natural and anthropogenic disturbance. In this thesis, I addressed how disturbances influence the vegetation and seed bank of Florida rosemary scrub. In Chapter One I evaluated changes in species composition and spatiotemporal pattern of the vegetation and seed bank along a gradient of disturbance. During the summers and winters of 2007-2009 percent ground cover and seed bank species composition were...
Show moreThe soil seed bank plays a dynamic role in the regeneration of plant communities after natural and anthropogenic disturbance. In this thesis, I addressed how disturbances influence the vegetation and seed bank of Florida rosemary scrub. In Chapter One I evaluated changes in species composition and spatiotemporal pattern of the vegetation and seed bank along a gradient of disturbance. During the summers and winters of 2007-2009 percent ground cover and seed bank species composition were assessed among replicates of three vegetation types subjected to minimal, moderate, and extreme anthropogenic disturbance (native rosemary scrub, degraded scrub, and agriculturally improved pasture, respectively). These vegetation types shared the same soil and topographic characteristics but differed in disturbance history. I found that species composition and spatial pattern varied with disturbance. In pastures the compositional and structural characteristics of rosemary scrub were lost and only native scrub species able to evade herbivory persisted in this community. Native and degraded scrub differed most from each other in species abundances and spatial pattern. Degraded scrub showed highest abundance of subshrubs and a spike moss species, while rosemary scrub was dominated by shrubs. The seed banks of scrub herbs in degraded scrub had a tendency towards a random spatial distribution that lacked association with aboveground cover. Conversely, rosemary scrub seed banks tended to have an aggregated distribution and were associated with occurrence of conspecific species aboveground, litter, and shrub cover. These results indicated a change in the spatial heterogeneity of the seed banks of scrub herbs in degraded scrub. In Chapter Two I evaluated changes in seed bank density with time-since-fire in native rosemary scrub. Due to large pulses of recruitment immediately after fire and population decline with time-since-fire, I predicted seed density with time-since-fire would follow a unimodal function with low density in early and late years post-fire, and highest density at intermediate time-since-fire. I compared seed density data among sites with different time-since-fire: two sites each of three, six, ten and 24 years time-since-fire and three long-unburned sites (> 24 years). Variability in seed bank composition and density increased with time-since-fire and only recently burned stands were distinctly different from the other time-since-fire age classes. Some species and functional groups did exhibit a quadratic or cubic association to time-since-fire (ruderal herbs, subshrubs, Ceratiola ericoides, Lechea cernua, Paronychia chartacea, Phyllanthus tenellus); however, timing of the peak in seed density varied depending on life span and age of reproductive maturity. Scrub herbs were the most abundant functional group in the seed bank and showed highest density in the first ten years post-fire. This pattern corresponds to the pattern of aboveground species abundance and suggests abundances above- and belowground are closely linked. Understanding the dynamics of the seed bank in both naturally and anthropogenically disturbed communities in Florida rosemary scrub is important for the restoration of scrub habitat and management of existing populations of endangered and threatened scrub species endemic to the Lake Wales Ridge in central Florida.
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Date Issued: 2010
Identifier: CFE0003108, ucf:48620
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003108

Title: FACTORS THAT INFLUENCE TRANSFER OF HAZARDOUS MATERIAL TRAINING: THE PERCEPTION OF SELECTED FIRE-FIGHTER TRAINEES AND SUPERVISORS.
Creator: Bhati, Divya, Gary Orwig, Stephen A. Sivo,, University of Central Florida
Abstract / Description: This study examined the influence of factors on transfer of training and was based on the work of Broad and Newstrom (1992). For the purpose of this study the Broad and Newstrom (1992) transfer of training barriers are rephrased into positive statements. The nine transfer of training factors are: (1) reinforcement on the job; (2) little interference from immediate (work) environment; (3) supportive organizational culture; (4) trainees' perception of training programs being practical; (5)...
Show moreThis study examined the influence of factors on transfer of training and was based on the work of Broad and Newstrom (1992). For the purpose of this study the Broad and Newstrom (1992) transfer of training barriers are rephrased into positive statements. The nine transfer of training factors are: (1) reinforcement on the job; (2) little interference from immediate (work) environment; (3) supportive organizational culture; (4) trainees' perception of training programs being practical; (5) trainees' perception of relevant training content; (6) trainees' being comfortable with change and associated effort; (7) trainer being supportive and inspiring; (8) trainees' perception of training being well designed/delivered, and (9) peer support. This study explored the degree to which these factors influenced transfer of training in terms of on-the-job application. The study found supportive organizational culture to be the strongest predictor of transfer of training to on-the-job application. In addition, the degree of influence of Broad and Newstrom's (1992) nine factors varied with the thirteen locations. The study also found perception gaps between fire fighter trainees and their supervisor on factors influencing transfer of training. They differed on four factors: Supportive organizational culture, Perception of training programs being practical, Trainer being supportive and inspiring, and Perception of training being well designed/delivered.
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Date Issued: 2007
Identifier: CFE0001850, ucf:47353
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001850

Title: IMPACT OF LANDSCAPE MANAGEMENT ON HOUSE MICE (MUS MUSCULUS) AND RED IMPORTED FIRE ANTS (SOLENOPSIS INVICTA).
Creator: Abelson, Jesse, Jenkins, David, University of Central Florida
Abstract / Description: Understanding of mechanisms that limit the abundance and distribution of species is central to ecology. The failure of mechanisms to regulate populations can result in population outbreaks. There have been two outbreaks of house mice in the past decade in central Florida. In my study, I examine the efficacy of landscape management in the form of mowing and plowed soil barriers to limit or prevent outbreaks of house mice in a former agricultural area. House mouse populations were highly...
Show moreUnderstanding of mechanisms that limit the abundance and distribution of species is central to ecology. The failure of mechanisms to regulate populations can result in population outbreaks. There have been two outbreaks of house mice in the past decade in central Florida. In my study, I examine the efficacy of landscape management in the form of mowing and plowed soil barriers to limit or prevent outbreaks of house mice in a former agricultural area. House mouse populations were highly variable, but were unaffected by mowing or plowed soil barriers. Red imported fire ants were ubiquitous in the study area regardless of land management treatments. Control of fire ants did not result in more house mice on treated plots.
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Date Issued: 2011
Identifier: CFE0003590, ucf:48899
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003590

fire (7)	+ -
Florida (4)	+ -
disturbance (3)	+ -
forensic science (3)	+ -
prescribed fire (3)	+ -

Aphelocoma coerulescens (2)	+ -
Fire (2)	+ -
Ignitable Liquids (2)	+ -
chemometrics (2)	+ -
ecology (2)	+ -
fire debris (2)	+ -
restoration (2)	+ -
scrub (2)	+ -
3-D structure (1)	+ -
Air -- Pollution potential -- Florida (1)	+ -
Behavioral ecology (1)	+ -
Biodiversity (1)	+ -
Butylbenzene (1)	+ -
Chemical Oxidation Kinetics (1)	+ -
Clitoria fragrans (1)	+ -
Coal fired power plants -- Florida (1)	+ -
Ecology (1)	+ -
Economic defensibility (1)	+ -
Ecosystem Engineer (1)	+ -
Extended Keystone Hypothesis (1)	+ -
Fire Debris (1)	+ -
Fire Debris Analysis (1)	+ -
Fire Debris Analysis and Pyrolysis Products (1)	+ -
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ETD Collection (33)	+ -
PRISM: Political & Rights Issues & Social Movements (1)	+ -

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Sigman, Michael (7)	+ -
Jenkins, David (6)	+ -
Campiglia, Andres (5)	+ -
Weishampel, John (4)	+ -

Noss, Reed (3)	+ -
Quintana-Ascencio, Pedro (3)	+ -
Behal, Aman (2)	+ -
Bridge, Candice (2)	+ -
Clausen, Christian (2)	+ -
King, Joshua (2)	+ -
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Ahmed, Kareem (1)	+ -
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