Nesting Ecology and Interactions Between Local and International Priorities for Hawksbill Sea Turtle (Eretmochelys Imbricata) Conservation on the Pacific Coast of Central America

Nesting Ecology and Interactions Between Local and International Priorities for Hawksbill Sea Turtle (Eretmochelys Imbricata) Conservation on the Pacific Coast of Central America
Author: Michael Joseph Liles
Publisher:
Total Pages:
Release: 2015
Genre:
ISBN:

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Despite human interaction with the biophysical environment since the beginning of human history, traditional research generally studied human and natural systems separately when addressing human-nature interactions. The purpose of my research is to better understand the nesting ecology and interactions between local and international priorities for hawksbill sea turtle (Eretmochelys imbricata) conservation in El Salvador and Nicaragua, where >90% of eastern Pacific hawksbill nesting occurs. In the first study, I explained the realities experienced by coastal residents who share habitat with hawksbills in El Salvador and then identified and clarified implications of discrepancies between these realities and international priorities for hawksbill conservation. The main findings were 1) primary importance of hawksbills is economic value attached to egg sales, but deeper cultural connections exist, 2) egg purchase by hatcheries benefits hawksbills and humans and 3) opportunities for local residents to participate in decision-making are limited and should be increased. In the second study, I characterized the microhabitat preferences and repeatability of nest-site choice by hawksbills, and then clarified the implications of doomed egg relocation programs on gene pools of hawksbills. I found 1) hawksbills preferred nest sites with abundant vegetation on dynamic beaches in mangrove estuaries, 2) female hawksbills exhibited local adaptations to differences in nesting habitat and 3) individual hawksbills consistently placed nests under high percentages of overstory vegetation, but were inconsistent in nest placement related to woody vegetation borders. In the third study, I generated and analyzed thermal profiles of hawksbill nest environments and estimated the sex ratios and physical condition of hatchling hawksbills under natural and artificial conditions. The primary findings were 1) minimal differences in temperature existed between sand depths, 2) adjustment of nest depth is unlikely to compensate for climate change, 3) in situ clutches incubated at higher temperatures and produced less fit offspring and 4) egg relocation can contribute to recovery efforts. The findings of these studies offer insight into interactions between hawksbill population dynamics and local community development on the Pacific coast of Central America, and demonstrate the value of implementing an evidence-based approach to guide public policy and conservation strategies. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/155524

The Leatherback Turtle

The Leatherback Turtle
Author: James R. Spotila
Publisher: JHU Press
Total Pages: 246
Release: 2015-10-30
Genre: Science
ISBN: 142141709X

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The most comprehensive book ever written on leatherback sea turtles. Weighing as much as 2,000 pounds and reaching lengths of over seven feet, leatherback turtles are the world’s largest reptile. These unusual sea turtles have a thick, pliable shell that helps them to withstand great depths—they can swim more than one thousand meters below the surface in search of food. And what food source sustains these goliaths? Their diet consists almost exclusively of jellyfish, a meal they crisscross the oceans to find. Leatherbacks have been declining in recent decades, and some predict they will be gone by the end of this century. Why? Because of two primary factors: human redevelopment of nesting beaches and commercial fishing. There are only twenty-nine index beaches in the world where these turtles nest, and there is immense pressure to develop most of them into homes or resorts. At the same time, longline and gill net fisheries continue to overwhelm waters frequented by leatherbacks. In The Leatherback Turtle, James R. Spotila and Pilar Santidrián Tomillo bring together the world’s leading experts to produce a volume that reveals the biology of the leatherback while putting a spotlight on the conservation problems and solutions related to the species. The book leaves us with options: embark on the conservation strategy laid out within its pages and save one of nature’s most splendid creations, or watch yet another magnificent species disappear.

Spatial Ecology of Hawksbill Turtles (Eretmochelys Imbricata) in the Eastern Pacific Ocean

Spatial Ecology of Hawksbill Turtles (Eretmochelys Imbricata) in the Eastern Pacific Ocean
Author:
Publisher:
Total Pages: 59
Release: 2011
Genre:
ISBN:

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Elucidating spatio-temporal movements of organisms is an integral component of wildlife management and life-history characterization. In the case of hawksbill turtles (Eretmochelys imbricata), adults have typically been described as coral reef dwellers, with females undertaking long post-nesting migrations. Until recently, hawksbills were thought to have been functionally extirpated in the eastern Pacific Ocean, a perspective changed by the identification of several substantial nesting rookeries. These discoveries provided new opportunities for research and conservation. Here we report on a region-wide satellite telemetry effort that has tracked thirteen adult female hawksbills in the eastern Pacific. In contrast to patterns of habitat use around coral reefs exhibited by their Caribbean conspecifics, the majority of hawksbills in the eastern Pacific occupied home ranges in mangrove estuaries. Post-nesting migrations for all turtles were relatively short (range = 18.1 km - 283.1 km) for the taxon, with several individuals remaining in local habitats after nesting. Also in contrast to previous research, dive computers indicated that adult hawksbills dove to and spent the majority of their time in the top 10 meters of the water column. Our findings suggest that common perceptions of hawksbill habitat use, dive behavior and migrations, largely Caribbean-based, have overlooked some key characteristics of this species displayed by other populations. Moreover, the consistent use of mangrove habitats, use of superficial waters and non-migratory behaviors represent a new life-history paradigm for the species and may explain why hawksbills went virtually undetected in the eastern Pacific for decades. From a conservation standpoint, the spatially restricted, shallow and neritic life cycles of hawksbills in the eastern Pacific present both threats to and conservation opportunities for the species. Although a large proportion (>60%) of turtle location points fell within protected areas, many of these sites lack enforcement and monitoring. Our results underscore the importance of strengthening protected area management, mangrove conservation and hawksbill research and conservation in the eastern Pacific. Furthermore, our findings highlight the variability in life-history strategies that sea turtles and other longlived marine wildlife may exhibit among ocean regions.

Examining Factors that Affect Community Participation in Sea Turtle Governance

Examining Factors that Affect Community Participation in Sea Turtle Governance
Author: José Ricardo Urteaga Augier
Publisher:
Total Pages: 0
Release: 2023
Genre:
ISBN:

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In this dissertation, I use a variety of quantitative and qualitative methods to study three cases of nesting sites of the critically endangered eastern Pacific hawksbill sea turtle (Eretmochelys imbricata). In these cases, conservation organizations have implemented projects regarded as successful in achieving positive socio-ecological outcomes. In the first two chapters, I review the contextual and structural issues that initially led to the over-extraction of sea turtle eggs and consider how conservation organization interventions changed those conditions. In the third chapter, I assess the use of Performance Payments for Conservation as one of the interventions that led to the success of those conservation programs. My overall findings suggest that, while conservation programs have succeeded in engaging communities and reversing the decline of sea turtle stocks, significant contextual and structural conditions must shift in order to achieve sustainable institutional change. Overall, this dissertation's findings exemplify the use of social-ecological system frameworks to examine conservation contexts in Central America. I provide novel data that contribute to interdisciplinary endeavors related to sea-turtle and community conservation broadly, as well as recommendations that can inform the further development of these and related initiatives.

Assessing the Effect of Nesting Habitat on Hatch and Emergence Success of Hawksbill Sea Turtles Eretmochelys Imbricata on Buck Island St. Croix USVI

Assessing the Effect of Nesting Habitat on Hatch and Emergence Success of Hawksbill Sea Turtles Eretmochelys Imbricata on Buck Island St. Croix USVI
Author: Manouchehr D. Afshar
Publisher:
Total Pages:
Release: 2021
Genre: Hawksbill turtle
ISBN:

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Human-driven climate change is causing global temperatures to rise at an unprecedented rate, which poses a threat to several species around the globe. Hawksbill sea turtles (Eretmochelys imbricata) are susceptible to the effects of rising temperatures because of their terrestrial nesting behavior. High temperature can have a lethal effect on incubating their terrestrial nesting behavior. High temperature can have a lethal effect on incubating hatchlings and is known to influence the hatchling sex ratio. This study investigates the relationship between hawksbill nesting environment and hatch and emergence success on Buck Island Reef National Monument, St. Croix, USVI. The environmental variables distance to highwater mark (m), root density (g/cm3), canopy cover (% shade), organic carbon content of nest soil (%), the maximum mean daily incubation temperature (°C), mean three-day maximum incubation temperature (°C), and the number of days incubation temperature exceeded 34°C (NOD>34°C) were tested for effect on hatch and emergence success. Data was collected from 27 hawksbill nests during the 2018 field season. Historical nesting data was used to investigate possible shifting of habitat use over the 31 years of data collection on Buck Island Reef National monument, St. Croix, USVI. Multiple linear regression indicated a significant relationship between canopy cover and hatch success, and the number of days incubation temperature exceeded 34°C (NOD>34°C) and emergence success. Canopy cover was shown to have a positive linear relationship with hatch success, and NOD>34°C was shown to have a negative relationship with emergence success. In addition, the results from this study showed no significant shift in nest-site selection since 1988 on Buck Island.

Nesting Trends of Hawksbill Sea Turtles (Eretmochelys Imbricata) at Sandy Point National Wildlife Refuge, St. Croix, U.S. Virgin Islands

Nesting Trends of Hawksbill Sea Turtles (Eretmochelys Imbricata) at Sandy Point National Wildlife Refuge, St. Croix, U.S. Virgin Islands
Author: Makayla Q. Kelso
Publisher:
Total Pages:
Release: 2022
Genre: Hawksbill turtle
ISBN:

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Sandy Point National Wildlife Refuge (SPNWR), located on St. Croix, U.S. Virgin Islands has been monitored for sea turtle nesting activity since the late 1970s. An analysis of hawksbill sea turtle (Eretmochelys imbricata) activities at the refuge has yet to be conducted. Historical records of hawksbills at SPNWR from 1981 to 2020 were compiled, digitized, and analyzed to assess trends in nesting activities across time as well as their distribution across the refuge. Using a linear model, trends in total hawksbill activities, nests, and nesting success were assessed across three distinct time frames: all records collected from 1981 to 2020, all data from 1993 to 2020 when records became more consistently available, and only records collected during the core nesting season (June-October) from 1993-2020. Additionally, chi-square analyses were conducted to identify significant differences in activity frequency, nesting success, and nest distribution across the three beaches (North, West, and South) at SPNWR. Overall, significant increasing trends were identified in total hawksbill activities and nests across all three time frames, which may be attributed to the successful conservation measures established throughout the region in the late 20th century. Nest density was similar on both the North and West beaches, though it was significantly lower on the South Beach. The North beach had the highest nesting success rate, likely due to its overall physical stability. While the hawksbill population at SPNWR is small compared to other nearby populations, the increasing trends identified here indicate that SPNWR may be well on its way to becoming a regionally significant nesting population. These trends may be indicative of successful local and regional management efforts, though continued standardized monitoring at Sandy Point is critical in further characterizing this population and monitoring the recovery of this species within the Wider Caribbean Region.

Hawksbill Sea Turtle (Eretmochelys Imbricata) Nesting Abundance in St. Thomas and Potential Impacts of Warming Sand Temperatures in the US Virgin Islands

Hawksbill Sea Turtle (Eretmochelys Imbricata) Nesting Abundance in St. Thomas and Potential Impacts of Warming Sand Temperatures in the US Virgin Islands
Author: Katie A. Ayres
Publisher:
Total Pages: 0
Release: 2022
Genre: Hawksbill turtle
ISBN:

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There are three sea turtle species commonly found nesting in the United States Virgin Islands (USVI), the green (Chelonia mydas), the leatherback (Dermochelys coriacea), and the hawksbill sea turtle (Eretmochelys imbricata). There have been programs established to consistently monitor sea turtle nesting activity on St. Croix and St. John. However, St. Thomas has lacked a consistent monitoring program to determine the extent to which its beaches are used as nesting habitat. This study focused on hawksbill nesting activity in 2021 and 2022 and identified four potentially important nesting beaches on St. Thomas (Abi Beach, Caret Bay, Hendriks Beach, and Neltjeberg Beach). A total of 15 hawksbill nests and one green nest were laid during the 2021 nesting season, and two hawksbill nests and six leatherback nests were laid during the 2022 nesting season. During the 2021 nesting season, hawksbill nests laid on St. Thomas and at the Sandy Point National Wildlife Refuge (SPNWR) on St. Croix were equipped with HOBO pendant data loggers to measure the internal temperatures of the nests, and sand temperatures were consistently recorded on these beaches in sections with and without canopy cover to investigate the potential hatchling sex ratios being produced on the two islands. Of the six nests on St. Thomas that had loggers between August and October 2021, two nests were estimated to produce 100% female hatchlings, and one nest was estimated to produce 100% male hatchlings, while the remaining three nests did not hatch. Nests laid on SPNWR between August and October were all estimated to have produced 100% females. There was a significant difference between the shaded sand and unshaded sand at most beaches on St. Thomas and SPNWR, with the shaded sand having cooler temperatures than the unshaded sand. St. Thomas beaches were found to have temperatures below 29°C in both the shaded and unshaded sections of the beach after October, while beaches at Sandy Point National Wildlife Refuge stayed at temperatures at or above 29°C until December 2021. These data suggest that St. Thomas has nesting habitat for all three species, and beaches here may be important male-producing beaches for hawksbill turtles.