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(1 - 9 of 9)
- Title
- A COMPARATIVE STATIC ANALYSIS FOR INVASIVE SPECIES MANAGEMENT UNDER RISK NEUTRAL PREFERENCES.
- Creator
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Safford, Pamela, Finnoff, David, University of Central Florida
- Abstract / Description
-
This thesis investigates the optimal ex-ante mix of self-protection and self-insurance technologies employed to reduce the risk of biological invaders in the presence of exogenous variables within the probability and damage functions. This is accomplished by using a theoretical endogenous risk model that extends previously developed frameworks. This thesis contributes to the previous work in two ways. (1) employing a general framework with simultaneous decision making over self-protection and...
Show moreThis thesis investigates the optimal ex-ante mix of self-protection and self-insurance technologies employed to reduce the risk of biological invaders in the presence of exogenous variables within the probability and damage functions. This is accomplished by using a theoretical endogenous risk model that extends previously developed frameworks. This thesis contributes to the previous work in two ways. (1) employing a general framework with simultaneous decision making over self-protection and self-insurance, this thesis analyzes how each parameter including income, the costs of each activity, an exogenous factor that affects only the probability of an invasion, and a separate exogenous factor that affects only the damages influence the level of self-protection and self-insurance. (2) the comparative static results are derived in the benchmark case of risk neutral preferences and qualitatively compared to an extended case of risk averse preferences. The results of the analysis indicate that under risk neutral preferences the signs of the comparative statics are unambiguous while under risk aversion the results are not clearly defined. Thus, the ambiguity of signs in the latter case can be attributed to the unobservable utility terms present under risk averse preferences. Therefore, it can be concluded that the model is not capable of yielding a decision criteria that will hold universally because the results are dependent on the nature of the risk averse curve
Show less - Date Issued
- 2004
- Identifier
- CFE0000156, ucf:46172
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000156
- Title
- IS THE EXOTIC BRAZILIAN PEPPER, SCHINUS TEREBINTHIFOLIUS, A THREAT TO MANGROVE ECOSYSTEMS IN FLORIDA?.
- Creator
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Donnelly, Melinda, Walters, Linda, University of Central Florida
- Abstract / Description
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Mangrove ecosystems are critical to Florida, providing economic resources to humans, and untold ecological resources to estuarine organisms. In Florida's estuaries, mangrove ecosystems have suffered significant losses due to natural and human disturbances; these disturbances potentially leave mangrove communities vulnerable to invasion by the opportunistic exotic, Schinus terebinthifolius (Brazilian pepper). Prior experiments have suggested that Schinus terebinthifolius is unable to survive...
Show moreMangrove ecosystems are critical to Florida, providing economic resources to humans, and untold ecological resources to estuarine organisms. In Florida's estuaries, mangrove ecosystems have suffered significant losses due to natural and human disturbances; these disturbances potentially leave mangrove communities vulnerable to invasion by the opportunistic exotic, Schinus terebinthifolius (Brazilian pepper). Prior experiments have suggested that Schinus terebinthifolius is unable to survive under marine conditions and poses no long term threat to mangrove systems. However, this contradicts field observations where Schinus terebinthifolius was found growing in the intertidal zone of Mosquito Lagoon alongside three native species of mangroves, Rhizophora mangle, Avicennia germinans and Laguncularia racemosa. The purpose of my study was to evaluate competition between the invasive S. terebinthifolius and these three native species of mangroves in the coastal estuarine system along the east coast of Central Florida in Canaveral National Seashore. The effects of competition were evaluated by testing the ability of S. terebinthifolius to: 1) chemically inhibit growth of mangrove propagules, 2) invade new coastal habitats by dispersing seeds in the water, 3) alter species richness and abundance of the flora when present in a mangrove system, and 4) recruit and survive in mangrove habitat. By better understanding the invasibility and impact of Schinus terebinthifolius on mangroves, coastal resource managers will be able to develop the most effective management strategies to prevent this exotic from altering the structure and productivity of the mangrove ecosystem.
Show less - Date Issued
- 2006
- Identifier
- CFE0000998, ucf:46713
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000998
- Title
- PREDICTING RISKS OF INVASION OF CAULERPA SPECIES IN FLORIDA.
- Creator
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Glardon, Christian, Walters, Linda, University of Central Florida
- Abstract / Description
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Invasions of exotic species are one of the primary causes of biodiversity loss on our planet (National Research Council 1995). In the marine environment, all habitat types including estuaries, coral reefs, mud flats, and rocky intertidal shorelines have been impacted (e.g. Bertness et al. 2001). Recently, the topic of invasive species has caught the public's attention. In particular, there is worldwide concern about the aquarium strain of the green alga Caulerpa taxifolia (Vahl) C. Agardh...
Show moreInvasions of exotic species are one of the primary causes of biodiversity loss on our planet (National Research Council 1995). In the marine environment, all habitat types including estuaries, coral reefs, mud flats, and rocky intertidal shorelines have been impacted (e.g. Bertness et al. 2001). Recently, the topic of invasive species has caught the public's attention. In particular, there is worldwide concern about the aquarium strain of the green alga Caulerpa taxifolia (Vahl) C. Agardh that was introduced to the Mediterranean Sea in 1984 from the Monaco Oceanographic Museum. Since that time, it has flourished in thousands of hectares of near-shore waters. More recently, C. taxifolia has invaded southern Californian and Australian waters. Since the waters of Florida are similar to the waters of the Mediterranean Sea and other invasive sites my study will focus on determining potential invasion locations in Florida. I will look at the present distribution of C. taxifolia - native strain in Florida as well as the distribution of the whole genus around the state. During this study, I address three questions: 1) What is the current distribution of Caulerpa spp. in Florida? 2) Can I predict the location of potential Caulerpa spp. invasions using a set of environmental parameters and correlate them to the occurrence of the algae with the support of Geographic Information System (GIS) maps? 3) Using the results of part two, is there an ecological preferred environment for one or all Caulerpa spp. in Florida? To answer these questions, I surveyed 24 areas in each of 6 zones chosen in a stratified manner along the Floridian coastline to evaluate the association of potential indicators Caulerpa. Latitude, presence or absence of seagrass beds, human population density, and proximity to marinas were chosen as the 4 parameters expected to correlate to Caulerpa occurrences. A logistic regression model assessing the association of Caulerpa occurrence with measured variables has been developed to predict current and future probabilities of Caulerpa spp. presence throughout the state. Fourteen different species of Caulerpa spp. were found in 26 of the 132 sites visited. There was a positive correlation between Caulerpa spp. and seagrass beds presence and proximity to marinas. There was a negative correlation with latitude and human population density. C. taxifolia – aquarium strain wasn't found. Percent correct for our model was of 61.5% for presence and 98.1% for absence. This prediction model will allow us to focus on particular areas for future surveys.
Show less - Date Issued
- 2006
- Identifier
- CFE0001041, ucf:46796
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001041
- Title
- LIMNOLOGICAL AND LANDSCAPE FACTORS AFFECTING USE OF MANUFACTURED PONDS BY THE INVASIVE CUBAN TREEFROG (OSTEOPILUS SEPTENTRIONALIS).
- Creator
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Nusinov, Terina, Fauth, John, University of Central Florida
- Abstract / Description
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Exotic amphibians are often detrimental to native biotas. In Florida, the exotic Cuban Treefrog (Osteopilus septentrionalis) eats native frogs and may outcompete them for resources. Cuban Treefrogs thrive in disturbed areas and around buildings, and often breed in manufactured wetlands such as retention ponds and borrow pits. This study identified limnological, landscape, and biotic characteristics that discouraged pond use by Cuban Treefrogs and promoted use by native amphibian species. I...
Show moreExotic amphibians are often detrimental to native biotas. In Florida, the exotic Cuban Treefrog (Osteopilus septentrionalis) eats native frogs and may outcompete them for resources. Cuban Treefrogs thrive in disturbed areas and around buildings, and often breed in manufactured wetlands such as retention ponds and borrow pits. This study identified limnological, landscape, and biotic characteristics that discouraged pond use by Cuban Treefrogs and promoted use by native amphibian species. I sampled natural and manufactured ponds in Orange County, Florida, for one year, using standard methods to estimate the species richness and relative abundance of amphibians and their potential fish and macroinvertebrate predators. I determined the relationship between the presence of Cuban Treefrogs and twelve limnological (% vegetation, slope, pond age, pH, % dissolved oxygen, air temperature, water temperature, turbidity, conductivity, depth, perimeter, and area) and seven landscape characteristics (% canopy closure over ponds, building density, distance to nearest building, road density, distance to nearest road, distance to nearest forest stand, and % forest cover), plus five biotic factors (native amphibian richness and abundance, fish richness and abundance, and macroinvertebrate abundance). No relationship existed between native amphibian abundance or species richness and the presence or absence of Cuban Treefrogs. Ponds with a greater percentage of vegetation, large perimeters, and low pH and turbidity had greater native amphibian species richness. Cuban Treefrogs were more likely to be found in ponds with a greater percentage of aquatic vegetation and small perimeters. My results show that building large retention ponds containing low-turbidity water will restrict colonization by Cuban Treefrogs and maintain species richness of native amphibians.
Show less - Date Issued
- 2006
- Identifier
- CFE0001000, ucf:46837
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001000
- Title
- BIOLOGY, ECOLOGY AND CONTROL OF THE INVASIVE CHANNELED APPLE SNAIL, POMACEA CANALICULATA.
- Creator
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Trexler, Christina, Fauth, John, University of Central Florida
- Abstract / Description
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Invasive species are detrimental to native biotas worldwide. Recently, Florida was invaded by a freshwater snail (Pomacea canaliculata) native to Argentina. This snail is a serious pest of rice crops in Asia, but little is known about its interactions within Florida ecosystems. Possible competitive exclusion of the native congener (P. paludosa) is a concern because it is the almost exclusive prey of the federally endangered Everglades snail kite (Rostrhamus sociabilis). My research consisted...
Show moreInvasive species are detrimental to native biotas worldwide. Recently, Florida was invaded by a freshwater snail (Pomacea canaliculata) native to Argentina. This snail is a serious pest of rice crops in Asia, but little is known about its interactions within Florida ecosystems. Possible competitive exclusion of the native congener (P. paludosa) is a concern because it is the almost exclusive prey of the federally endangered Everglades snail kite (Rostrhamus sociabilis). My research consisted of three parts. First, to identify possible methods to control P. canaliculata in the egg stage, I experimentally evaluated the effects of photoperiod, substrate availability, and food type and availability on hatching success and hatchling survival. None of these factors significantly affected hatching or survival, suggesting that P. canaliculata could invade many water bodies. Second, I used a randomized block design to assess the separate and combined effects of population density and food availability on growth and spawning of P. canaliculata. Food availability but not density significantly affected growth; snails fed less food grew less, but neither factor affected spawning. Third, I used a replacement series design to assess competition between P. canaliculata and P. paludosa under food limitation. For both species, snails fed less grew significantly less, and snails exposed to greater congener densities spawned less than when exposed to conspecifics only. While my results predict that P. paludosa should exclude P. canaliculata, previous literature and current invasions suggest that the exotic snail may co-exist with its North American congener.
Show less - Date Issued
- 2011
- Identifier
- CFE0003877, ucf:48725
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003877
- Title
- The effects of non-native species on two life-stages of the Eastern oyster (<)i(>)Crassostrea virginica(<)/i(>).
- Creator
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Yuan, Wei, Walters, Linda, Hoffman, Eric, Fauth, John, Scarpa, John, University of Central Florida
- Abstract / Description
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Since their recent introductions into Florida waters, three nonnative species [()Perna viridis() Linnaeus, 1758 (Asian green mussel), ()Mytella charruana() d'Orbigny, 1846 (charru mussel) and ()Megabalanus coccopoma() Darwin, 1854 (pink titan acorn barnacle)] have expanded both north and south along the Atlantic coast. Very little research has been done to understand how these nonnative species interact with the native eastern oyster (()Crassostrea virginica() Gmelin, 1791), which is a...
Show moreSince their recent introductions into Florida waters, three nonnative species [(<)i(>)Perna viridis(<)/i(>) Linnaeus, 1758 (Asian green mussel), (<)i(>)Mytella charruana(<)/i(>) d'Orbigny, 1846 (charru mussel) and (<)i(>)Megabalanus coccopoma(<)/i(>) Darwin, 1854 (pink titan acorn barnacle)] have expanded both north and south along the Atlantic coast. Very little research has been done to understand how these nonnative species interact with the native eastern oyster ((<)i(>)Crassostrea virginica(<)/i(>) Gmelin, 1791), which is a keystone species that provides important ecological services and economic benefits. To test the potential effects of (<)i(>)P. viridis, M. charruana(<)/i(>) and (<)i(>)M. coccopoma(<)/i(>) on (<)i(>)C. virginica(<)/i(>), I addressed the following questions: 1a) Does the presence of nonnative species decrease oyster larval settlement? 1b) Do oyster larvae avoid settling on oyster shells to which nonnative species are attached? 2a) Do nonnative species decrease survival of juvenile oysters (spat)? and 2b) Do nonnative species hinder spat growth? My manipulative experiments showed that the tested nonnative species influenced settlement, growth and survival of (<)i(>)C. virginica(<)/i(>) in unique ways. (<)i(>)Megabalanus coccopoma(<)/i(>) decreased the total number of settled oyster larvae, but did not influence larval preference or survival and growth of spat. (<)i(>)Perna viridis(<)/i(>) negatively influenced larval settlement and oyster larvae avoided settling on shells of (<)i(>)P. viridis(<)/i(>). (<)i(>)Mytella charruana(<)/i(>) had no influence on the total number of settled larvae but oyster larvae avoided settling on oyster shell with (<)i(>)M. charruana(<)/i(>) or on the mussel shells themselves. Furthermore, both nonnative mussels negatively affected the survival of juvenile oysters, but only (<)i(>)M. charruana(<)/i(>) reduced spat growth. These three nonnative species should be classified as invasive species because all had negative effects on the native oyster (<)i(>)C. virginica(<)/i(>).
Show less - Date Issued
- 2014
- Identifier
- CFE0005448, ucf:50377
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005448
- Title
- From pet to pest? The potential global range and food web effects of a generalist carnivore.
- Creator
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Bevan, Hannah, Jenkins, David, Noss, Reed, Campbell, Todd, University of Central Florida
- Abstract / Description
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The Nile monitor lizard [Varanus niloticus (Linnaeus, 1766)] is a generalist carnivore, native to Sub-Saharan Africa and the Nile River but now established in North America as a result of the pet trade. Once introduced, they are a potential invasive threat to native wildlife. Here, I create ensemble species distribution models (SDMs) to predict the global distribution of this generalist carnivore given current and future climate conditions. I then quantify the monitor's potential effects on...
Show moreThe Nile monitor lizard [Varanus niloticus (Linnaeus, 1766)] is a generalist carnivore, native to Sub-Saharan Africa and the Nile River but now established in North America as a result of the pet trade. Once introduced, they are a potential invasive threat to native wildlife. Here, I create ensemble species distribution models (SDMs) to predict the global distribution of this generalist carnivore given current and future climate conditions. I then quantify the monitor's potential effects on 85 food webs representing (>)900 different species within the projected regions based on stomach content data. Climate, vegetation, and elevation data are used for 507 georeferenced observation points from the Nile monitor's native range to produce current and future (2070) ensemble SDMs. Explanatory variables are evaluated as ten alternative models organized in three subsets according to model assumptions. The true skill statistic (TSS), sensitivity, and specificity were used to assess model performance, and the best subset was averaged to represent an ensemble model. Food web impacts after the generalist predator's addition are determined by changes in nine metrics of food web structure. The most predictive (TSS scores ?0.87) ensemble SDM was based on the MARS and FDA algorithms using elevation and climate for current and future conditions. This model shows that, if introduced, Nile monitors will likely spread into many regions in the Americas, the Caribbean, Madagascar, Southeast Asia, and Australia. Assuming unabated carbon emissions by 2070, climate change will enhance that potential range. Adding Nile monitors to food webs generally increases overall trophic links, connectance, link density, and fraction of intermediate taxa, with decreases in the fraction of top and basal taxa. These results are consistent with a generalist predator that affects many species and is likely to affect food web stability. The potential Nile monitor range is vast and encompasses multiple biodiversity hotspots. Given many strong food web interactions by this generalist predator, vulnerable regions should actively prohibit/regulate Nile monitors as pets, enforce those restrictions, and promote exotic pet amnesty programs. Southern US states should especially act soon to prevent spread of the Nile monitor to the Neotropics from its current introduced population in Florida and as released pets.
Show less - Date Issued
- 2016
- Identifier
- CFE0006441, ucf:51446
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006441
- Title
- The next "killer" algae? Assessing and mitigating invasion risk for aquarium strains of the marine macroalgal genus Chaetomorpha.
- Creator
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Odom, Rachel, Walters, Linda, Hinkle, Charles, Hanisak, M. Dennis, University of Central Florida
- Abstract / Description
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Biological invasions threaten the ecological integrity of natural ecosystems. Anthropogenic introductions of non-native species can displace native flora and fauna, altering community compositions and disrupting ecosystem services. One often-overlooked vector for such introductions is the release of aquarium organisms into aquatic ecosystems. Following detrimental aquarium-release invasions by the (")killer alga(") Caulerpa taxifolia, aquarium hobbyists and professions began promoting the use...
Show moreBiological invasions threaten the ecological integrity of natural ecosystems. Anthropogenic introductions of non-native species can displace native flora and fauna, altering community compositions and disrupting ecosystem services. One often-overlooked vector for such introductions is the release of aquarium organisms into aquatic ecosystems. Following detrimental aquarium-release invasions by the (")killer alga(") Caulerpa taxifolia, aquarium hobbyists and professions began promoting the use of other genera of macroalgae as (")safe(") alternatives. The most popular of these marine aquarium macroalgae, the genus Chaetomorpha, is analyzed here for invasion risk. Mitigation strategies are also evaluated. I found that the propensity for reproduction by vegetative fragmentation displayed by aquarium strains of Chaetomorpha poses a significant invasion threat(-)fragments of aquarium Chaetomorpha are able to survive from sizes as small as 0.5 mm in length, or one intact, live cell. Fragments of this size and larger are generated in large quantities in online and retail purchases of Chaetomorpha, and introduction of these fragments would likely result in viable individuals for establishment in a variety of geographic and seasonal environmental conditions. Mitigation of invasion risk was assessed in two ways(-)rapid response to a potential introduction by chemical eradication and prevention through safe hobbyist disposal. I tested the effectiveness of five chemicals used as algicides and found that acetic acid was highly effective at limiting survival and growth of aquarium Chaetomorpha. Chlorine bleach, copper sulfate and rock salt were effective at limiting growth but were inconsistent or ineffective in reducing survival of algal fragments. The algicide Sonar limited neither survival nor growth. If aquarium strains of Chaetomorpha are released, chemical eradication presents a viable management strategy, particularly through the use of acetic acid. A more cost-effective strategy, however, would be preventing introductions; thus safe alternatives to release were determined for hobbyist disposal of unwanted or excess aquarium Chaetomorpha. Here I present the minimum exposure durations necessary to induce full mortality of aquarium Chaetomorpha through boiling, microwaving, freezing, desiccation and exposure to freshwater. Hobbyist disposal by any of these methods would constitute safe alternatives to introduction of the alga into natural environments. Such preventative measures will inform outreach campaigns in order to limit the potential for aquarium-release introduction.
Show less - Date Issued
- 2012
- Identifier
- CFE0004624, ucf:49918
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004624
- Title
- Evaluation of the three-dimensional patterns and ecological impacts of the invasive Old World climbing fern (Lygodium microphyllum).
- Creator
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Maldonado, Alexis, Weishampel, John, VonHolle, Mary, Hinkle, Charles, University of Central Florida
- Abstract / Description
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Invasion by non-native species has had significant ecological and economic impacts on a global scale. In the state of Florida, Old World climbing fern (Lygodium microphyllum) is an invasive plant listed by FLEPPC as a category one invader with significant ecological impacts that threaten native plant diversity. This species relies on existing vegetative structures for support to climb into the forest canopy and forms dense mats that cover tree crowns. This subsequently affects the resources...
Show moreInvasion by non-native species has had significant ecological and economic impacts on a global scale. In the state of Florida, Old World climbing fern (Lygodium microphyllum) is an invasive plant listed by FLEPPC as a category one invader with significant ecological impacts that threaten native plant diversity. This species relies on existing vegetative structures for support to climb into the forest canopy and forms dense mats that cover tree crowns. This subsequently affects the resources available to other species present. Quantifying the structural changes due to the presence of this species has proved logistically difficult, especially on a large spatial scale.Airborne LiDAR (Light Detection And Ranging) technology is a form of remote sensing that measures the elevation of surfaces over a site. In this study I utilized LiDAR to calculate various forest structure metrics at Jonathan Dickinson State Park (JDSP) in Hobe Sound, Florida across various management frequencies and densities of Old World climbing fern. These data were used to quantify the degree to which this invasive species alters forest structure across these two gradients. I also recorded species composition in the field to relate how Old World climbing fern impacts native plant diversity. Structural measurements including average canopy height, height of median energy (HOME), rugosity, canopy openness, and vertical structural diversity (LHDI) were calculated for a total of three hundred 0.25ha sites stratified by invasion density and management frequency.Using a combination of univariate and multivariate statistical analyses I found that the presence of Old World Climbing fern altered the physical structure of the forest communities itivinvades. Higher percent cover of Old World climbing fern decreased structural diversity while increased management effort was found to mitigate those impacts. The management for Old World Climbing fern was also found to impact both species richness and diversity at JDSP. I also demonstrated that there were several species that were not found and others that were more common in the presence of Old World climbing fern and that there was a relationship between management and what species were present. The results show that both Old World climbing fern and the management practices used to control it have had significant ecological impacts on the natural communities in South Florida.
Show less - Date Issued
- 2014
- Identifier
- CFE0005206, ucf:50651
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005206
