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- Title
- Factors affecting the hatching success of loggerhead sea turtle eggs: (Caretta caretta caretta).
- Creator
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McGehee, M. Angela, Elmhart, L.M., Natural Sciences
- Abstract / Description
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University of Central Florida College of Natural Sciences Thesis; Clutches of eggs wore collected from nesting loggerhead sea turtles (Caretta caretta caretta) on Merritt Island, Florida, during June - August 1977. Of these, 46 clutches were selected for experimentation to determine the extent to which certain factors affect hatching success. Twelve clutches were divided into subsamples which were incubated in sand maintained at 0, 25, 50, 75, and 100% moisture. Another twelve clutches were...
Show moreUniversity of Central Florida College of Natural Sciences Thesis; Clutches of eggs wore collected from nesting loggerhead sea turtles (Caretta caretta caretta) on Merritt Island, Florida, during June - August 1977. Of these, 46 clutches were selected for experimentation to determine the extent to which certain factors affect hatching success. Twelve clutches were divided into subsamples which were incubated in sand maintained at 0, 25, 50, 75, and 100% moisture. Another twelve clutches were divided into subsamples and incubated in sand kept moist with the following percentages of seawater: 0 (distilled water), 25, 50, 75, and 100%; subsamples from four other clutches were subjected to the effects of one tidal inundation. Eggs from four of the clutches used in the moisture and salinity experiments were monitored for changes in size. Fifteen clutches were divided into subsamples which were kept in incubators maintained at 20, 24, 27, 30, 32, 35, and 38[degrees]C; subsamples from seven of these clutches were moved from unfavorable to optimal temperatures to study their ability to recover from stress. Three clutches were selected for an experiment to determine the effects of handling on hatching success; the following year, another five clutches were used for similar studies. Some of the hatchling turtles produced in this project were abnormal, and these were discussed in depth. From the experiments, it was determined that 25% moisture, 0-25% seawater, and 27[degrees]C produced the maximum percent hatch. The effects of handling on hatching success depended variably on the time and manner of handling. The optimum values indicated in the experiments closely approximated values for moisture, salinity, and temperature obtained from natural turtle nests on the beach.
Show less - Date Issued
- 1979
- Identifier
- CFR0004341, ucf:52974
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0004341
- Title
- Modeling Survival of Immature Loggerheads (Caretta caretta) and Green Turtles (Chelonia mydas) from 10 Years of Mark-Recapture Data at the Florida Power and Light St. Lucie Plant.
- Creator
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Sterner, Andrew, Weishampel, John, Ehrhart, Llewellyn, Walters, Linda, Breininger, David, University of Central Florida
- Abstract / Description
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Loggerheads (Caretta caretta) are listed as Threatened and green turtles (Chelonia mydas) are listed as Endangered under the United States Endangered Species Act. While green turtle nest production in Florida has increased markedly in recent years, loggerhead nest production has followed a more tenuous path. Reasons for these differences are unknown. Limited demographic information is available for these species of conservation concern. I used Barker models, which incorporated mark-recapture,...
Show moreLoggerheads (Caretta caretta) are listed as Threatened and green turtles (Chelonia mydas) are listed as Endangered under the United States Endangered Species Act. While green turtle nest production in Florida has increased markedly in recent years, loggerhead nest production has followed a more tenuous path. Reasons for these differences are unknown. Limited demographic information is available for these species of conservation concern. I used Barker models, which incorporated mark-recapture, live-resight and dead recovery data, implemented in Program MARK. These models were used to estimate apparent survival for immature loggerhead ((<)85cm SCL) and green turtle ((<)60cm SCL) populations foraging in the Atlantic Ocean adjacent to the Florida Power and Light St. Lucie Plant on Hutchinson Island, Florida between 2002 and 2011. My results indicated annual apparent survival was decreasing (from 0.75 to 0.59) for resident immature loggerheads and was stable (~0.81) for resident immature green turtles over the ten year study period. I found that permanent emigration models were better supported than no movement models for both species. Size (straight carapace length) was found to be an important covariate for survival and fidelity parameters in the green turtle analysis but not in the loggerhead analysis. My study is the first to compare survival of two species of immature marine turtles foraging at the same location in the Atlantic. These estimates are also the first available survival estimates for immature marine turtle populations in Florida based on modern mark-recapture techniques, filling a critical knowledge gap. This information is vitally important for managers when evaluating the long-term recovery of these endangered species.
Show less - Date Issued
- 2013
- Identifier
- CFE0004755, ucf:49770
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004755
- Title
- IMPACT OF INCREASED GREEN TURTLE NESTING ON LOGGERHEAD FITNESS.
- Creator
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Carmichael, Amanda R, Mansfield, Kate, University of Central Florida
- Abstract / Description
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Marine turtles exhibit strong fidelity to their nesting beaches, making the conservation of nesting beaches important for ensuring successful sea turtle populations. Conservation of these nesting beaches involves understanding how species interact with the environment and each other, and understanding how environmental change and population growth can affect the suitability of the nesting habitat. The Archie Carr National Wildlife Refuge (ACNWR) is unusual in its high density of sea turtle...
Show moreMarine turtles exhibit strong fidelity to their nesting beaches, making the conservation of nesting beaches important for ensuring successful sea turtle populations. Conservation of these nesting beaches involves understanding how species interact with the environment and each other, and understanding how environmental change and population growth can affect the suitability of the nesting habitat. The Archie Carr National Wildlife Refuge (ACNWR) is unusual in its high density of sea turtle nesting by two species: green (Chelonia mydas) and loggerhead (Caretta caretta) turtles. The ACNWR in Melbourne Beach, Florida was established in 1991 due to the high density of loggerhead nesting, but in the time since it was established there has been a significant increase in green turtle nesting, from fewer than 50 nests in 1982 to over 15,000 in 2017. With such a high density of these two species in one relatively small area (21 kilometers of beach), the two species may compete for space. This is especially true for green turtles, which disturb large amounts of sand during their nesting process; in 2017, we observed 338 loggerhead clutches disturbed by nesting females during nesting surveys, nearly all of which were disturbed by green turtles. Using observed spatial and temporal nesting patterns for both green turtles and loggerheads on the ACNWR, I examined the effects these species may have on each other's nests now and in the future. Additionally, green turtles and loggerheads nest in different densities along the length of the ACNWR, with green turtles more concentrated in the southern portions of the Refuge. Finally, green turtle nesting begins and peaks approximately one month later on the ACNWR than loggerhead nesting. For each of these metrics, there is both considerable overlap and distinct separation between the two species. By using these metrics in a modeling approach, I estimated the probability of nest disturbance by a subsequently nesting female, ranging from 0 to 0.105, and how these probabilities are predicted to change over time with a growing green turtle population. Evaluating the carrying capacity of this beach is important in the context of habitat disturbance, including climate change and an increase in storm frequency, and informing adaptive management strategies for effective conservation.
Show less - Date Issued
- 2018
- Identifier
- CFH2000284, ucf:45878
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000284
- Title
- EFFECTS OF A SHORE PROTECTION PROJECT ON LOGGERHEAD AND GREEN TURTLE NESTING ACTIVITY AND REPRODUCTION IN BREVARD COUNTY, FLORIDA.
- Creator
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Brock, Kelly, Ehrhart, Llewellyn, University of Central Florida
- Abstract / Description
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Marine turtle reproductive success is strongly correlated with the stability and quality of the nesting environment. Because females show fidelity to key nesting beaches, the management and physical characteristics of these beaches directly affect future generations of marine turtles and may be essential for the recovery of these threatened and endangered species. The impacts of beach restoration on loggerhead turtles (Caretta caretta) and on green turtles (Chelonia mydas) were investigated....
Show moreMarine turtle reproductive success is strongly correlated with the stability and quality of the nesting environment. Because females show fidelity to key nesting beaches, the management and physical characteristics of these beaches directly affect future generations of marine turtles and may be essential for the recovery of these threatened and endangered species. The impacts of beach restoration on loggerhead turtles (Caretta caretta) and on green turtles (Chelonia mydas) were investigated. Previous studies concerning beach nourishment projects have focused on loggerhead turtles. I compared data between nourished and non-nourished areas and between loggerhead and green turtles. I found, at one season post-nourishment, negative effects on nesting success and no significant effect on reproductive success for both loggerheads and established the same relationships with green turtles. Physical attributes of the fill sand, which did not facilitate acute scarp formation or severe compaction, did not physically impede turtles in their attempts to nest. Instead, the decrease in nesting success was attributed to an absence of abiotic and or biotic factors that cue nesting behavior. The increase in loggerhead nesting success rates during the second season post-nourishment was attributed to the equilibration process of the seaward crest of the berm. After the beach was restored, both species of turtles placed nests significantly farther from the water in the nourished area than in the non-nourished area. Green turtles nested on or near the dune and loggerheads nested on the seaward crest of the berm. The tendency of loggerheads to nest closer to the water resulted in more loggerhead than green turtle nests being "washed out" by erosion during the equilibration process. There was a significant increase in hatching success only for loggerheads when wash outs were excluded, thus illustrating the importance of nest placement and the detrimental effects of the equilibration process to the reproductive success of loggerheads. A decrease in reproductive output occurred during the first season post-nourishment. The reduction in the estimated total number of hatchlings produced (reproductive output) was a consequence of decreased nesting success lowering nest numbers. This reduction demonstrates that, regardless of similar reproductive success rates, marine turtles incurred net losses during the first season following nourishment. These results further reveal the impacts of decreased nesting success and the importance of minimizing excessive non-nesting emergences associated with beach nourishment.
Show less - Date Issued
- 2005
- Identifier
- CFE0000493, ucf:46365
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000493
- Title
- FACTORS AFFECTING PREDATION OF MARINE TURTLE EGGS BY RACCOONS AND GHOST CRABS ON CANAVERAL NATIONAL SEASHORE, FL.
- Creator
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Brown, Justin, Roth, James, University of Central Florida
- Abstract / Description
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Changes in abundance of interactive species can have cascading, community-wide effects (Soulé et al. 2003). Raccoons (Procyon lotor) prey on a competitor for marine turtle eggs, the Atlantic ghost crab (Ocypode quadrata). Conservation of marine turtles often includes managing raccoons--the most obvious egg predator--which may have broader ecological effects, and unknown effects on egg predation. Neither the relationship between raccoons and ghost crab density nor the effects of ghost...
Show moreChanges in abundance of interactive species can have cascading, community-wide effects (Soulé et al. 2003). Raccoons (Procyon lotor) prey on a competitor for marine turtle eggs, the Atlantic ghost crab (Ocypode quadrata). Conservation of marine turtles often includes managing raccoons--the most obvious egg predator--which may have broader ecological effects, and unknown effects on egg predation. Neither the relationship between raccoons and ghost crab density nor the effects of ghost crab density on egg predation are well understood. I studied raccoon-ghost crab interactions and the effects of environmental variation on their activity during the 2007 marine turtle nesting season on Canaveral National Seashore, FL. My goal was to model predator activity and identify efficient management strategies to reduce egg predation. Raccoon activity increased with increasing habitat diversity and edge of the dominant cover type, coastal strand. Raccoon activity increased locally and became less variable near segments of beach accessed for human recreation, but activity was greater on undeveloped beach, where habitat diversity and edge were greater. Ghost crab density and size were primarily affected by sand characteristics and recreation but decreased with increasing raccoon activity in June, which may have contributed to sustained declines in ghost crab density. Hatching success of marine turtles decreased with increasing ghost crab egg predation, suggesting ghost crabs are an important cause of egg mortality and not merely scavengers on unhatched eggs. Egg predation by ghost crabs was unrelated to ghost crab density or size, likely a result of monitoring limitations, but raccoon activity increased with increasing egg predation by ghost crabs, supporting previous research and experimental evidence suggesting ghost crabs can facilitate secondary nest predation by raccoons. This indirect interaction has strong implications for marine turtle conservation, because its strength may increase with increasing ghost crab density, potentially negating the effects of raccoon removal.
Show less - Date Issued
- 2009
- Identifier
- CFE0002667, ucf:48235
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002667
- Title
- Migratory connectivity and carry-over effects in Northwest Atlantic loggerhead turtles (Caretta caretta, L.).
- Creator
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Ceriani, Simona, Weishampel, John, Ehrhart, Llewellyn, Walters, Linda, Quintana-Ascencio, Pedro, Roth, James, Valdes, Eduardo, University of Central Florida
- Abstract / Description
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Migration is a widespread and complex phenomenon in nature that has fascinated humans for centuries. Connectivity among populations influences their demographics, genetic structure and response to environmental change. Here, I used the loggerhead turtle (Caretta caretta, L.) as a study organism to address questions related to migratory connectivity and carry-over effects using satellite telemetry, stable isotope analysis and GIS interpolation methods. Telemetry identified foraging areas...
Show moreMigration is a widespread and complex phenomenon in nature that has fascinated humans for centuries. Connectivity among populations influences their demographics, genetic structure and response to environmental change. Here, I used the loggerhead turtle (Caretta caretta, L.) as a study organism to address questions related to migratory connectivity and carry-over effects using satellite telemetry, stable isotope analysis and GIS interpolation methods. Telemetry identified foraging areas previously overlooked for loggerheads nesting in Florida. Next, I validated and evaluated the efficacy of intrinsic markers as a complementary and low cost tool to assign loggerhead foraging regions in the Northwest Atlantic Ocean (NWA), using both a spatially implicit and spatially explicit (isoscapes) approach. I then focused on the nesting beaches and developed a common currency for isotopic studies based on unhatched eggs, which provide a non-invasive and non-destructive method for more extensive sampling to elucidate isotopic patterns across broader spatiotemporal scales. Lastly, I found that intra-population variations in foraging strategies affect annual and long-term reproductive output of loggerheads nesting in Florida. Understanding geospatial linkages is critical to the fostering of appropriate management and conservation strategies for migratory species. My multi-faceted approach contributes to the growing body of literature exploring migratory connectivity and carry-over effects.
Show less - Date Issued
- 2014
- Identifier
- CFE0005470, ucf:50390
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005470
- Title
- HISTORICAL RESPONSES OF MARINE TURTLES TO GLOBAL CLIMATE CHANGE AND JUVENILE LOGGERHEAD RECRUITMENT IN FLORIDA.
- Creator
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Reece, Joshua, Parkinson, Christopher, University of Central Florida
- Abstract / Description
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Marine turtle conservation is most successful when it is based on sound data incorporating life history, historical population stability, and gene flow among populations. This research attempts to provide that information through two studies. In chapter I, I identify historical patterns of gene flow, population sizes, and contraction/expansion during major climatic shifts. In chapter II, I reveal a life history characteristic of loggerhead turtles previously undocumented. I identify a pattern...
Show moreMarine turtle conservation is most successful when it is based on sound data incorporating life history, historical population stability, and gene flow among populations. This research attempts to provide that information through two studies. In chapter I, I identify historical patterns of gene flow, population sizes, and contraction/expansion during major climatic shifts. In chapter II, I reveal a life history characteristic of loggerhead turtles previously undocumented. I identify a pattern of juvenile recruitment to foraging grounds proximal to their natal nesting beach. This pattern results in a predictable recruitment pattern from juvenile foraging ground aggregations to local rookeries. This research will provide crucial information to conservation managers by demonstrating how sensitive marine turtles are to global climate change. In the second component of my research, I demonstrate how threats posed to juvenile foraging grounds will have measurable effects on rookeries proximal to those foraging grounds. The addition of this basic life history information will have dramatic effects on marine turtle conservation in the future, and will serve as the basis for more thorough, forward-looking recovery plans.
Show less - Date Issued
- 2005
- Identifier
- CFE0000341, ucf:46281
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000341
- Title
- Determining the impacts of beach restoration on loggerhead (Caretta caretta) and green turtle (Chelonia mydas) nesting patterns and reproductive success along Florida's Atlantic coast.
- Creator
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Hays, Allison, Weishampel, John, Ehrhart, Llewellyn, Mota, Mario, Hinkle, Charles, University of Central Florida
- Abstract / Description
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Artificial beach nourishment, the most common method to mitigate coastal erosion in the United States, is also considered the most ecologically friendly alternative for shoreline stabilization. However, this habitat alteration has the potential to impact nesting marine turtles and developing hatchlings. The first objective of this study was to determine how nourishing beaches with two different design templates affects loggerhead (Caretta caretta) and green turtle (Chelonia mydas) nesting...
Show moreArtificial beach nourishment, the most common method to mitigate coastal erosion in the United States, is also considered the most ecologically friendly alternative for shoreline stabilization. However, this habitat alteration has the potential to impact nesting marine turtles and developing hatchlings. The first objective of this study was to determine how nourishing beaches with two different design templates affects loggerhead (Caretta caretta) and green turtle (Chelonia mydas) nesting success, the ratio of nests to the total number of nests and non-nesting emergences, and reproductive success, the ratio of hatched and emerged hatchlings to the total number of eggs deposited. Two types of restoration designs exist along the southern Brevard County, FL coastline, which supports some of the highest density loggerhead and green turtle nesting worldwide. Since 2005, approximately 35 kilometers of beach have undergone 1) full-scale restoration (typically called nourishment), where sand was added above and below the mean high tide line (2005, 2010) or 2) dune restoration, where sand was placed on the dune (2005, 2006, 2008, 2009). To quantify the effects of these restoration types, we used a Before-After-Control-Impact-Paired Series (BACIPS) model, which tests for significance between the difference in nesting success rates at the impact (engineered) and control sites (natural beach) before and after restoration (?). For loggerheads, there was a significant difference in ? after dune restoration during the years of construction (2005, 2006, 2008, and 2009; p(<)0.001) and one year post-construction (2007; p(<)0.05 and 2010; p(<)0.001). After full-scale restoration, there was a significant difference in ? during the years of construction (2005 and 2010; p (<)0.001) and one year post-construction (2006; p(<)0.001). For green turtles, there was a significant difference in ? after dune restoration during two of the four years of construction (2006; p(<)0.05 and 2008; p(<)0.01) and one of the two one-year post-construction years (2010; p(<)0.05). After full-scale restoration, the significant difference in ? lasted every season (2005-2010; p(<)0.001). There were no significant differences in ? for loggerhead or green turtle reproductive success rates after either type of restoration. The second objective was to use the different restoration designs to study what beach characteristics function as loggerhead nesting cues to explain why altering the beach decreases nesting success rates. We examined beach elevation and slope, sand moisture content, sand grain size, beach width, and distance traveled. Logistic regression model selection found all variables were important (R2=0.75). Further examination of trends, with each crawl divided into quarters, found beach slope served as a nesting cue. In all study sites except one, when turtles false crawled, the beach flattened out in the final quarter of the crawl. Conversely, in nesting emergences, the final quarter rose at a steeper slope than the previous quarter. Additionally, model selection found variables important in nest site selection were also important in hatching (R2=0.44) and emergence (R2=0.45) success. These results offer new insight into how and why marine turtle nesting patterns change after artificial nourishment, providing information necessary to nourish beaches in a more (")turtle-friendly(") manner. ?
Show less - Date Issued
- 2012
- Identifier
- CFE0004332, ucf:49447
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004332
