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Margaritoulis D, Lourenço G, Riggall TE, Rees AF. Thirty-Eight Years of Loggerhead Turtle Nesting in Laganas Bay, Zakynthos, Greece: A Review. CHELONIAN CONSERVATION AND BIOLOGY 2022. [DOI: 10.2744/ccb-1531.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Dimitris Margaritoulis
- ARCHELON, the Sea Turtle Protection Society of Greece, Solomou 57, GR-10432 Athens, Greece [; ; ; ]
| | - Gonçalo Lourenço
- ARCHELON, the Sea Turtle Protection Society of Greece, Solomou 57, GR-10432 Athens, Greece [; ; ; ]
| | - Thomas E. Riggall
- ARCHELON, the Sea Turtle Protection Society of Greece, Solomou 57, GR-10432 Athens, Greece [; ; ; ]
| | - Alan F. Rees
- ARCHELON, the Sea Turtle Protection Society of Greece, Solomou 57, GR-10432 Athens, Greece [; ; ; ]
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Minor Sea Turtle Nesting Areas May Remain Unnoticed without Specific Monitoring: The Case of the Largest Mediterranean Island (Sicily, Italy). Animals (Basel) 2022; 12:ani12091221. [PMID: 35565647 PMCID: PMC9101241 DOI: 10.3390/ani12091221] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/02/2022] [Accepted: 05/03/2022] [Indexed: 11/17/2022] Open
Abstract
Simple Summary Before protecting sea turtles’ nesting sites from coastal development, these sites must be identified and evaluated. This is particularly difficult with minor nesting sites distributed over large areas. We report on the case of Sicily, the largest Mediterranean island with 464 km of sandy shores, where sea turtle nesting activity was basically unknown until recent years when specific projects focused on this topic. This may be the case for many other areas. A total of 323 nests have been reported in the 1944–2021 period (mostly in the last decade). However, the real number of nests occurring annually is still unknown and more research and monitoring is needed. In sea turtles, sex is determined by the incubation temperature, with high temperatures producing more females, and with global warming the scarcity of males may become a problem. Nests in Sicily seem to produce more males and therefore this area may be important for the species’ conservation in the future. Abstract Identifying coastal tracts suitable for sea turtle reproduction is crucial for sea turtle conservation in a context of fast coastal development and climate change. In contrast to nesting aggregations, diffuse nesting is elusive and assessing nesting levels is challenging. A total of 323 nesting events by the loggerhead sea turtle Caretta caretta have been reported in Sicily, the largest Mediterranean island, in the 1944–2021 period, mostly in the last decade. Specific monitoring efforts are the most likely explanation for such an increase and shows that sea turtle nesting may be underestimated or completely ignored in many areas with scattered nesting. The real nesting level along the 464 km sandy shores of Sicily is still unknown and more research is needed. The observed incubation period was relatively long (57 d) suggesting that a majority of males are produced in Sicily, in contrast to the typical female-biased sex ratio of sea turtles. In a context of climate warming producing sex ratios more skewed towards females, the potential of Sicily as a male-producing area should be further investigated. Other reproductive parameters are provided, such as clutch size and hatching and emergence success. A negative effect of relocation on the latter two was observed.
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3
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Incorporating Geographical Scale and Multiple Environmental Factors to Delineate the Breeding Distribution of Sea Turtles. DRONES 2021. [DOI: 10.3390/drones5040142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Temperature is often used to infer how climate influences wildlife distributions; yet, other parameters also contribute, separately and combined, with effects varying across geographical scales. Here, we used an unoccupied aircraft system to explore how environmental parameters affect the regional distribution of the terrestrial and marine breeding habitats of threatened loggerhead sea turtles (Caretta caretta). Surveys spanned four years and ~620 km coastline of western Greece, encompassing low (<10 nests/km) to high (100–500 nests/km) density nesting areas. We recorded 2395 tracks left by turtles on beaches and 1928 turtles occupying waters adjacent to these beaches. Variation in beach track and inwater turtle densities was explained by temperature, offshore prevailing wind, and physical marine and terrestrial factors combined. The highest beach-track densities (400 tracks/km) occurred on beaches with steep slopes and higher sand temperatures, sheltered from prevailing offshore winds. The highest inwater turtle densities (270 turtles/km) occurred over submerged sandbanks, with warmer sea temperatures associated with offshore wind. Most turtles (90%) occurred over nearshore submerged sandbanks within 10 km of beaches supporting the highest track densities, showing the strong linkage between optimal marine and terrestrial environments for breeding. Our findings demonstrate the utility of UASs in surveying marine megafauna and environmental data at large scales and the importance of integrating multiple factors in climate change models to predict species distributions.
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Schofield G, Dickson LCD, Westover L, Dujon AM, Katselidis KA. COVID-19 disruption reveals mass-tourism pressure on nearshore sea turtle distributions and access to optimal breeding habitat. Evol Appl 2021; 14:2516-2526. [PMID: 34548882 PMCID: PMC8444759 DOI: 10.1111/eva.13277] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 06/28/2021] [Accepted: 06/29/2021] [Indexed: 11/30/2022] Open
Abstract
Quantifying the extent to which animals detect and respond to human presence allows us to identify pressure (disturbance) and inform conservation management objectively; however, obtaining baselines against which to compare human impact is hindered in areas where human activities are already well established. For example, Zakynthos Island (Greece, Mediterranean) receives around 850,000 visitors each summer, while supporting an important loggerhead sea turtle rookery (~300 individuals/season). The coronavirus (COVID-19)-driven absence of tourism in May-June 2020 provided an opportunity to evaluate the distribution dynamics of this population in the absence (2020) vs. presence (2018 and 2019) of visitors using programmed unmanned aerial system (UAS) surveys. Ambient sea temperature transitioned from suboptimal for breeding in May to optimal in late June, with turtle distribution appearing to shift from shallow (to benefit from waters 3-5°C above ambient) to deeper waters in 2018 and 2019, but not 2020. The 2020 data set demonstrated that increased tourism pressure, not temperature, drives turtles offshore. Specifically, >50% of turtles remained within 100 m of shore at densities of 25-50 visitors/km, even when sea temperature rose, with 2018 and 2019 data supporting this trend. Reduced access to warmer, nearshore waters by tourism could delay the onset of nesting and increase the length of the egg maturation period between nesting events (internesting interval) at this site. A coastal refuge zone could be delimited in May-June where touristic infrastructure is minimal, but also where turtles frequently aggregate. In conclusion, sea turtles appear capable of perceiving changes in the level of human pressure at fine spatial and temporal scales and adjusting their distribution accordingly.
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Affiliation(s)
- Gail Schofield
- School of Biological and Chemical Sciences Queen Mary University of London London UK
| | - Liam C D Dickson
- School of Biological and Chemical Sciences Queen Mary University of London London UK
| | - Lucy Westover
- School of Biological Sciences University of Bristol Bristol UK
| | - Antoine M Dujon
- Centre for Integrative Ecology School of Life and Environmental Sciences Deakin University Geelong Vic. Australia
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Pusapati C, Manoharakrishnan M, Phillott AD, Shanker K. Effect of Hatchery Nest Environment on Olive Ridley (Lepidochelys olivacea) Hatchling Performance. CHELONIAN CONSERVATION AND BIOLOGY 2021. [DOI: 10.2744/ccb-1450.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Chandana Pusapati
- TERI School of Advanced Studies, Plot 10, Institutional Area, Vasant Kunj, New Delhi 110070, India []
| | | | - Andrea D. Phillott
- Dakshin Foundation, 1818, 9th Cross, 5th Main, Sahakar Nagar B block, Bangalore 560092, Karnataka, India []
| | - Kartik Shanker
- Dakshin Foundation, 1818, 9th Cross, 5th Main, Sahakar Nagar B block, Bangalore 560092, Karnataka, India []
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Patrício AR, Hawkes LA, Monsinjon JR, Godley BJ, Fuentes MMPB. Climate change and marine turtles: recent advances and future directions. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01110] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Climate change is a threat to marine turtles that is expected to affect all of their life stages. To guide future research, we conducted a review of the most recent literature on this topic, highlighting knowledge gains and research gaps since a similar previous review in 2009. Most research has been focussed on the terrestrial life history phase, where expected impacts will range from habitat loss and decreased reproductive success to feminization of populations, but changes in reproductive periodicity, shifts in latitudinal ranges, and changes in foraging success are all expected in the marine life history phase. Models have been proposed to improve estimates of primary sex ratios, while technological advances promise a better understanding of how climate can influence different life stages and habitats. We suggest a number of research priorities for an improved understanding of how climate change may impact marine turtles, including: improved estimates of primary sex ratios, assessments of the implications of female-biased sex ratios and reduced male production, assessments of the variability in upper thermal limits of clutches, models of beach sediment movement under sea level rise, and assessments of impacts on foraging grounds. Lastly, we suggest that it is not yet possible to recommend manipulating aspects of turtle nesting ecology, as the evidence base with which to understand the results of such interventions is not robust enough, but that strategies for mitigation of stressors should be helpful, providing they consider the synergistic effects of climate change and other anthropogenic-induced threats to marine turtles, and focus on increasing resilience.
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Affiliation(s)
- AR Patrício
- MARE - Marine and Environmental Sciences Centre, ISPA - Instituto Universitário, 1149-041 Lisbon, Portugal
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn TR10 9FE, UK
| | - LA Hawkes
- Hatherley Laboratories, College of Life and Environmental Sciences, University of Exeter, Streatham Campus, Exeter EX4 4PS, UK
| | - JR Monsinjon
- Department of Zoology and Entomology, Rhodes University, Grahamstown 6139, South Africa
| | - BJ Godley
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn TR10 9FE, UK
| | - MMPB Fuentes
- Marine Turtle Research, Ecology and Conservation Group, Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, FL 32306, USA
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Booth DT, Dunstan A, Robertson K, Tedeschi J. Egg viability of green turtles nesting on Raine Island, the world’s largest nesting aggregation of green turtles. AUST J ZOOL 2021. [DOI: 10.1071/zo21024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Egg inviability at oviposition is a possible explanation for the high rate of early-stage embryo death of eggs laid by green turtles at Raine Island, the largest green turtle nesting aggregation in the world. We tested this possibility by assessing egg viability of freshly laid eggs. We found that green turtle eggs laid at Raine Island have high viability at their time of laying, and that there was no relationship between egg viability and early-stage embryo death or hatching success within a clutch. Hence, the inviable egg at oviposition hypothesis cannot explain the high death rate of early-stage embryos that is characteristic of green turtle clutches laid at Raine Island.
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Gammon M, Fossette S, McGrath G, Mitchell N. A Systematic Review of Metabolic Heat in Sea Turtle Nests and Methods to Model Its Impact on Hatching Success. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.556379] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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Rowe CL, Liang D, Woodland RJ. Effects of constant and fluctuating incubation temperatures on hatching success and hatchling traits in the diamondback terrapin (Malaclemys terrapin) in the context of the warming climate. J Therm Biol 2020; 88:102528. [PMID: 32126003 DOI: 10.1016/j.jtherbio.2020.102528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 01/23/2020] [Accepted: 01/27/2020] [Indexed: 10/25/2022]
Abstract
As global temperatures continue to rise, so too will the nest temperatures of many species of turtles. Yet for most turtle species, including the estuarine diamondback terrapin (Malaclemys terrapin), there is limited information on embryonic sensitivity to elevated temperature. We incubated eggs of M. terrapin at three, mean temperatures (31, 34, 37 °C) under two thermal exposure regimes (constant or semi-naturally fluctuating temperature) and measured hatching success, developmental rate, and hatchling size. Hatching success was 100% at 31 °C and 67% at 34 °C, respectively; at 37 °C, all eggs failed early in the incubation period. These values were unaffected by exposure regime. The modeled LT50 (temperature that was lethal to 50% of the test population) was 34.0 °C in the constant and 34.2 °C in the fluctuating thermal regime, reflecting a steep decline in survival between 33 and 35 °C. Hatchlings having been incubated at a constant 34 °C hatched sooner than those incubated at 31 °C under either constant or fluctuating temperature. Hatchlings were smaller in straight carapace length (CL) and width after having been incubated at 34 °C compared to 31 °C. Larger (CL) hatchlings resulted from fluctuating temperature conditions relative to constant temperature conditions, regardless of mean temperature. Based upon recent temperatures in natural nests, the M. terrapin population studied here appears to possess resiliency to several degrees of elevated mean nest temperatures, beyond which, embryonic mortality will likely sharply increase. When considered within the mosaic of challenges that Maryland's M. terrapin face as the climate warms, including ongoing habitat losses due to sea level rise and impending thermal impacts on bioenergetics and offspring sex ratios, a future increase in embryonic mortality could be a critical factor for a population already experiencing ecological and physiological challenges due to climate change.
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Affiliation(s)
- Christopher L Rowe
- University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, 146 Williams Street, P.O. Box 38, Solomons, MD, 20688, USA.
| | - Dong Liang
- University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, 146 Williams Street, P.O. Box 38, Solomons, MD, 20688, USA
| | - Ryan J Woodland
- University of Maryland Center for Environmental Science, Chesapeake Biological Laboratory, 146 Williams Street, P.O. Box 38, Solomons, MD, 20688, USA
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Staines MN, Booth DT, Limpus CJ. Microclimatic effects on the incubation success, hatchling morphology and locomotor performance of marine turtles. ACTA OECOLOGICA 2019. [DOI: 10.1016/j.actao.2019.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Patrício AR, Varela MR, Barbosa C, Broderick AC, Catry P, Hawkes LA, Regalla A, Godley BJ. Climate change resilience of a globally important sea turtle nesting population. GLOBAL CHANGE BIOLOGY 2019; 25:522-535. [PMID: 30567014 DOI: 10.1111/gcb.14520] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 09/30/2018] [Indexed: 06/09/2023]
Abstract
Few studies have looked into climate change resilience of populations of wild animals. We use a model higher vertebrate, the green sea turtle, as its life history is fundamentally affected by climatic conditions, including temperature-dependent sex determination and obligate use of beaches subject to sea level rise (SLR). We use empirical data from a globally important population in West Africa to assess resistance to climate change within a quantitative framework. We project 200 years of primary sex ratios (1900-2100) and create a digital elevation model of the nesting beach to estimate impacts of projected SLR. Primary sex ratio is currently almost balanced, with 52% of hatchlings produced being female. Under IPCC models, we predict: (a) an increase in the proportion of females by 2100 to 76%-93%, but cooler temperatures, both at the end of the nesting season and in shaded areas, will guarantee male hatchling production; (b) IPCC SLR scenarios will lead to 33.4%-43.0% loss of the current nesting area; (c) climate change will contribute to population growth through population feminization, with 32%-64% more nesting females expected by 2120; (d) as incubation temperatures approach lethal levels, however, the population will cease growing and start to decline. Taken together with other factors (degree of foraging plasticity, rookery size and trajectory, and prevailing threats), this nesting population should resist climate change until 2100, and the availability of spatial and temporal microrefugia indicates potential for resilience to predicted impacts, through the evolution of nest site selection or changes in nesting phenology. This represents the most comprehensive assessment to date of climate change resilience of a marine reptile using the most up-to-date IPCC models, appraising the impacts of temperature and SLR, integrated with additional ecological and demographic parameters. We suggest this as a framework for other populations, species and taxa.
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Affiliation(s)
- Ana R Patrício
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
- MARE - Marine and Environmental Sciences Centre, ISPA - Instituto Universitário, Lisbon, Portugal
| | - Miguel R Varela
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Castro Barbosa
- Institute of Biodiversity and Protected Areas of Guinea-Bissau, Bissau, Guinea-Bissau
| | | | - Paulo Catry
- MARE - Marine and Environmental Sciences Centre, ISPA - Instituto Universitário, Lisbon, Portugal
| | - Lucy A Hawkes
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
| | - Aissa Regalla
- Institute of Biodiversity and Protected Areas of Guinea-Bissau, Bissau, Guinea-Bissau
| | - Brendan J Godley
- Centre for Ecology and Conservation, University of Exeter, Penryn, UK
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Casale P, Broderick AC, Camiñas JA, Cardona L, Carreras C, Demetropoulos A, Fuller WJ, Godley BJ, Hochscheid S, Kaska Y, Lazar B, Margaritoulis D, Panagopoulou A, Rees AF, Tomás J, Türkozan O. Mediterranean sea turtles: current knowledge and priorities for conservation and research. ENDANGER SPECIES RES 2018. [DOI: 10.3354/esr00901] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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13
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Booth DT. Incubation temperature induced phenotypic plasticity in oviparous reptiles: Where to next? JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:343-350. [DOI: 10.1002/jez.2195] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 05/17/2018] [Accepted: 05/18/2018] [Indexed: 11/10/2022]
Affiliation(s)
- David T. Booth
- School of Biological Sciences; The University of Queensland; Queensland Australia
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14
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Read TC, Petit M, Magnan M, Booth D. Going back to the roots: finding a strategy for the management of nesting loggerhead sea turtles in New Caledonia. AUST J ZOOL 2018. [DOI: 10.1071/zo19051] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Incubation temperature plays a vital role in sea turtle life history because it influences embryonic growth, sex determination and hatchling attributes such as body size, residual yolk size, self-righting ability, crawling speed and swimming speed. For these reasons there is concern that predicted increases in air temperature, as a result of global warming, will increase nest temperatures and result in decreased hatching success, decrease or cease male hatchling production, and decreased hatchling quality. In a previous study examining incubation temperature at a loggerhead turtle (Caretta caretta) rookery located at La Roche Percée, New Caledonia, high nest temperatures and root invasion by beach morning glory (Ipomoea pes-caprae) were found to adversely affect hatching success and locomotor performance. In the current study, we relocated loggerhead turtle nests into shaded hatcheries. Shading nests decreased sand and nest temperatures and was predicted to increase male hatchling production slightly, but nest emergence success was decreased due to invasion of cottonwood (Hibiscus tiliaceus) roots into some nests. Using shaded structures is a viable and affordable management option to counteract the high sand temperatures found on some sea turtle nesting beaches, but these shade structures need to be located some distance from trees and other plants to ensure that root penetration into nests does not adversely affect nest emergence success.
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Fuentes MM, Monsinjon J, Lopez M, Lara P, Santos A, dei Marcovaldi MA, Girondot M. Sex ratio estimates for species with temperature-dependent sex determination differ according to the proxy used. Ecol Modell 2017. [DOI: 10.1016/j.ecolmodel.2017.09.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Affiliation(s)
- David T. BOOTH
- School of Biological Sciences; The University of Queensland; St Lucia Queensland Australia
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Patel SH, Morreale SJ, Saba VS, Panagopoulou A, Margaritoulis D, Spotila JR. Climate Impacts on Sea Turtle Breeding Phenology in Greece and Associated Foraging Habitats in the Wider Mediterranean Region. PLoS One 2016; 11:e0157170. [PMID: 27332550 PMCID: PMC4917093 DOI: 10.1371/journal.pone.0157170] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 05/25/2016] [Indexed: 11/18/2022] Open
Abstract
Sea turtles are vulnerable to climate change impacts in both their terrestrial (nesting beach) and oceanic habitats. From 1982 to 2012, air and sea surface temperatures at major high use foraging and nesting regions (n = 5) of loggerhead turtles (Caretta caretta) nesting in Greece have steadily increased. Here, we update the established relationships between sea surface temperature and nesting data from Zakynthos (latitude: 37.7°N), a major nesting beach, while also expanding these analyses to include precipitation and air temperature and additional nesting data from two other key beaches in Greece: Kyparissia Bay (latitude: 37.3°N) and Rethymno, Crete (latitude: 35.4°N). We confirmed that nesting phenology at Zakynthos has continued to be impacted by breeding season temperature; however, temperature has no consistent relationship with nest numbers, which are declining on Zakynthos and Crete but increasing at Kyparissia. Then using statistically downscaled outputs of 14 climate models assessed by the Intergovernmental Panel on Climate Change (IPCC), we projected future shifts in nesting for these populations. Based on the climate models, we projected that temperature at the key foraging and breeding sites (Adriatic Sea, Aegean Sea, Crete, Gulf of Gabès and Zakynthos/Kyparissia Bay; overall latitudinal range: 33.0°-45.8°N) for loggerhead turtles nesting in Greece will rise by 3-5°C by 2100. Our calculations indicate that the projected rise in air and ocean temperature at Zakynthos could cause the nesting season in this major rookery to shift to an earlier date by as much as 50-74 days by 2100. Although an earlier onset of the nesting season may provide minor relief for nest success as temperatures rise, the overall climatic changes to the various important habitats will most likely have an overall negative impact on this population.
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Affiliation(s)
- Samir H. Patel
- Department of Biodiversity, Earth and Environmental Science, Drexel University, Philadelphia, PA, 19104, United States of America
- * E-mail:
| | - Stephen J. Morreale
- Cornell University, Department of Natural Resources, Ithaca, NY, 14850, United States of America
| | - Vincent S. Saba
- NOAA NMFS NEFSC, c/o Geophysical Fluid Dynamics Laboratory, Princeton University Forrestal Campus, Princeton, NJ, 08544, United States of America
| | - Aliki Panagopoulou
- Department of Biodiversity, Earth and Environmental Science, Drexel University, Philadelphia, PA, 19104, United States of America
- ARCHELON, the Sea Turtle Protection Society of Greece, 104 32 Athens, Greece
| | | | - James R. Spotila
- Department of Biodiversity, Earth and Environmental Science, Drexel University, Philadelphia, PA, 19104, United States of America
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Hill JE, Paladino FV, Spotila JR, Tomillo PS. Shading and watering as a tool to mitigate the impacts of climate change in sea turtle nests. PLoS One 2015; 10:e0129528. [PMID: 26030883 PMCID: PMC4452221 DOI: 10.1371/journal.pone.0129528] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 05/11/2015] [Indexed: 11/18/2022] Open
Abstract
Increasing sand temperatures resulting from climate change may negatively impact sea turtle nests by altering sex ratios and decreasing reproductive output. We analyzed the effect of nest shading and watering on sand temperatures as climate mitigation strategies in a beach hatchery at Playa Grande, Costa Rica. We set up plots and placed thermocouples at depths of 45cm and 75cm. Half of the plots were shaded and half were exposed to the sun. Within these exposure treatments, we applied three watering treatments over one month, replicating local climatic conditions experienced in this area. We also examined gravimetric water content of sand by collecting sand samples the day before watering began, the day after watering was complete, and one month after completion. Shading had the largest impact on sand temperature, followed by watering and depth. All watering treatments lowered sand temperature, but the effect varied with depth. Temperatures in plots that received water returned to control levels within 10 days after watering stopped. Water content increased at both depths in the two highest water treatments, and 30 days after the end of water application remained higher than plots with low water. While the impacts of watering on sand temperature dissipate rapidly after the end of application, the impacts on water content are much more lasting. Although less effective at lowering sand temperatures than shading, watering may benefit sea turtle clutches by offsetting negative impacts of low levels of rain in particularly dry areas. Prior to implementing such strategies, the natural conditions at the location of interest (e.g. clutch depth, environmental conditions, and beach characteristics) and natural hatchling sex ratios should be taken into consideration. These results provide insight into the effectiveness of nest shading and watering as climate mitigation techniques and illustrate important points of consideration in the crafting of such strategies.
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Affiliation(s)
- Jacob E. Hill
- Department of Biology, College of Arts and Sciences, Indiana University-Purdue University Fort Wayne, Fort Wayne, Indiana, United States of America
- * E-mail:
| | - Frank V. Paladino
- Department of Biology, College of Arts and Sciences, Indiana University-Purdue University Fort Wayne, Fort Wayne, Indiana, United States of America
| | - James R. Spotila
- Department of Biodiversity, Earth and Environmental Science, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Pilar Santidrián Tomillo
- Population Ecology Group, Institut Mediterrani d’ Estudis Avançats, IMEDEA (CSIC-UIB), Mallorca, Spain
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Schofield G, Scott R, Katselidis KA, Mazaris AD, Hays GC. Quantifying wildlife-watching ecotourism intensity on an endangered marine vertebrate. Anim Conserv 2015. [DOI: 10.1111/acv.12202] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- G. Schofield
- Centre for Integrative Ecology; School of Life and Environmental Sciences; Deakin University; Warrnambool Vic. Australia
| | - R. Scott
- The Future Ocean Cluster of Excellence; GEOMAR-Helmholtz Centre for Ocean Research; Kiel Germany
| | - K. A. Katselidis
- Department of Environmental and Natural Resources Management; University of Patras; Agrinio Greece
- National Marine Park of Zakynthos; Zakynthos Greece
| | - A. D. Mazaris
- Department of Ecology, School of Biology; Aristotle University of Thessaloniki; Thessaloniki Greece
| | - G. C. Hays
- Centre for Integrative Ecology; School of Life and Environmental Sciences; Deakin University; Warrnambool Vic. Australia
- Department of Biosciences; Swansea University; Swansea UK
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Wyneken J, Lolavar A. Loggerhead sea turtle environmental sex determination: Implications of moisture and temperature for climate change based predictions for species survival. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2015; 324:295-314. [DOI: 10.1002/jez.b.22620] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 03/02/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Jeanette Wyneken
- Department of Biological Sciences; Florida Atlantic University; Boca Raton Florida
| | - Alexandra Lolavar
- Department of Biological Sciences; Florida Atlantic University; Boca Raton Florida
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Assessing the efficacy of direct conservation interventions: clutch protection of the leatherback marine turtle in the Dominican Republic. ORYX 2014. [DOI: 10.1017/s0030605313001488] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
AbstractThe beaches of Jaragua National Park in the Dominican Republic are the country's last known major nesting site for the leatherback marine turtle Dermochelys coriacea. This nesting aggregation is threatened by widespread illegal egg take, and clutch relocation and artificial incubation have been carried out as protection measures since 1974. We assess the efficacy of such efforts and investigate how artificial incubation may be influencing the success and sex ratios of clutches. We compare hatching success, incubation duration and embryo mortality in in-situ clutches (n = 43) with those incubated artificially at sites in the east and west of the Park (n = 35 and n = 31, respectively). Our results show that in the west, artificial incubation significantly decreases hatching success in clutches. In the east the duration of incubation is increased, which we predict would result in an increase in the number of males from these clutches. Clutch relocation is currently the only viable conservation option for clutches on eastern beaches because of illegal egg take but action is needed to ensure that the natural sex ratio is not distorted. However, on the western beaches in situ clutch incubation seems possible through beach protection. Further community engagement and enforcement are required to improve conservation measures at eastern beaches if long-term, less sustainable intervention is to be avoided.
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Freedberg S, Debenport SJ. Weakened purifying selection leads to elevated mutation load under environmental sex determination. J Evol Biol 2014; 27:643-52. [PMID: 24506704 DOI: 10.1111/jeb.12335] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 01/07/2014] [Accepted: 01/08/2014] [Indexed: 11/28/2022]
Abstract
In many gonochoristic taxa, sex is influenced by developmental environment, a system that can lead to temporal fluctuations in offspring sex ratio. Demographic models suggest that only short-lived species with environmental sex determination (ESD) are negatively impacted by sex-ratio fluctuations, yet these models fail to account for the potential mutation load associated with reductions in genetically effective population sizes. In this study, we developed a series of individual-based simulation models that explore the fixation rates of mildly deleterious alleles under different sex-determining systems and examine the impacts of variation in lifespan and offspring sex ratio. Populations with ESD exhibited increases in fixation rates in both short- and long-lived populations, but substantial increases were limited to populations characterized by a combination of high sex-ratio variation and short lifespan. Fixation rates were negatively associated with effective population size, indicating that purifying selection operates less efficiently under ESD relative to genotypic sex determination. Reductions in effective population size could be attributed to both intragenerational forces (unequal sex ratio) and intergenerational forces (variable census population sizes). Levels of temporal sex-ratio variation calculated from wild populations of ESD species were capable of yielding large increases in fixation rates, although this relationship was strongly mediated by lifespan. Our results may help to explain the limited phylogenetic distribution of ESD in short-lived taxa.
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Affiliation(s)
- S Freedberg
- Department of Biology, St. Olaf College, Northfield, MN, USA
| | - S J Debenport
- Department of Plant Pathology, Ohio State University, Columbus, OH, USA
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Pike DA. Forecasting the viability of sea turtle eggs in a warming world. GLOBAL CHANGE BIOLOGY 2014; 20:7-15. [PMID: 24106042 DOI: 10.1111/gcb.12397] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 09/03/2013] [Accepted: 09/09/2013] [Indexed: 06/02/2023]
Abstract
Animals living in tropical regions may be at increased risk from climate change because current temperatures at these locations already approach critical physiological thresholds. Relatively small temperature increases could cause animals to exceed these thresholds more often, resulting in substantial fitness costs or even death. Oviparous species could be especially vulnerable because the maximum thermal tolerances of incubating embryos is often lower than adult counterparts, and in many species mothers abandon the eggs after oviposition, rendering them immobile and thus unable to avoid extreme temperatures. As a consequence, the effects of climate change might become evident earlier and be more devastating for hatchling production in the tropics. Loggerhead sea turtles (Caretta caretta) have the widest nesting range of any living reptile, spanning temperate to tropical latitudes in both hemispheres. Currently, loggerhead sea turtle populations in the tropics produce nearly 30% fewer hatchlings per nest than temperate populations. Strong correlations between empirical hatching success and habitat quality allowed global predictions of the spatiotemporal impacts of climate change on this fitness trait. Under climate change, many sea turtle populations nesting in tropical environments are predicted to experience severe reductions in hatchling production, whereas hatching success in many temperate populations could remain unchanged or even increase with rising temperatures. Some populations could show very complex responses to climate change, with higher relative hatchling production as temperatures begin to increase, followed by declines as critical physiological thresholds are exceeded more frequently. Predicting when, where, and how climate change could impact the reproductive output of local populations is crucial for anticipating how a warming world will influence population size, growth, and stability.
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Escobedo-Galván AH. Temperature-dependent sex determination in an uncertain world: advances and perspectives. REV MEX BIODIVERS 2013. [DOI: 10.7550/rmb.32441] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Fuentes MMPB, Pike DA, Dimatteo A, Wallace BP. Resilience of marine turtle regional management units to climate change. GLOBAL CHANGE BIOLOGY 2013; 19:1399-1406. [PMID: 23505145 DOI: 10.1111/gcb.12138] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Revised: 01/07/2013] [Accepted: 01/09/2013] [Indexed: 06/01/2023]
Abstract
Enhancing species resilience to changing environmental conditions is often suggested as a climate change adaptation strategy. To effectively achieve this, it is necessary first to understand the factors that determine species resilience, and their relative importance in shaping the ability of species to adjust to the complexities of environmental change. This is an extremely challenging task because it requires comprehensive information on species traits. We explored the resilience of 58 marine turtle regional management units (RMUs) to climate change, encompassing all seven species of marine turtles worldwide. We used expert opinion from the IUCN-SSC Marine Turtle Specialist Group (n = 33 respondents) to develop a Resilience Index, which considered qualitative characteristics of each RMU (relative population size, rookery vulnerability, and genetic diversity) and non climate-related threats (fisheries, take, coastal development, and pollution/pathogens). Our expert panel perceived rookery vulnerability (the likelihood of functional rookeries becoming extirpated) and non climate-related threats as having the greatest influence on resilience of RMUs to climate change. We identified the world's 13 least resilient marine turtle RMUs to climate change, which are distributed within all three major ocean basins and include six of the world's seven species of marine turtle. Our study provides the first look at inter- and intra-species variation in resilience to climate change and highlights the need to devise metrics that measure resilience directly. We suggest that this approach can be widely used to help prioritize future actions that increase species resilience to climate change.
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