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Cui L, Yang C, Zhang D, Lin S, Zhao W, Liu P. Beneficial Effects of Warming Temperatures on Embryonic and Hatchling Development in a Low-Latitude Margin Population of the High-Latitude Lizard Lacerta agilis. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.845309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The effects of warming temperatures on embryonic and hatchling development are critical for determining the vulnerability of species to climate warming. However, these effects have rarely been investigated in high-latitude oviparous species, particularly in their low-latitude margin populations. This study investigated the embryonic and hatchling development and fitness-related traits of a low-latitude margin population of a high-latitude lizard (Lacerta agilis). These traits were examined under present (24°C), moderate warming (27 and 30°C), and severe warming scenarios (33°C). Based on embryonic and hatchling responses to thermal variation, this study aimed to predict the vulnerability of the early life stages of low-latitude margin population of Lacerta agilis to climate warming. The incubation period of the low-latitude margin population of Lacerta agilis decreased as the temperature increased from 24 to 33°C. Hatching success was similar at 24, 27, and 30°C but decreased significantly at 33°C. No differences with temperature were observed for hatchling snout-vent length and hatchling body mass. The sprint speed was higher for hatchlings from temperatures of 24 and 33°C. The growth rate of hatchlings was highest at 30°C; however, the survival rate of hatchlings was not affected by the thermal environment. This study demonstrated that even for a low-latitude margin population of the high-latitude lizard, Lacerta agilis, moderate warming (i.e., 27 and 30°C) would benefit embryonic and hatchling development. This was indicated by the results showing higher hatching success, growth rate, and survival rate. However, if temperatures increase above 33°C, development and survival would be depressed significantly. Thus, low-latitude margin population of high-latitude species Lacerta agilis would benefit from climate warming in the near future but would be under stress if the nest temperature exceeded 30°C.
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Lockley EC, Eizaguirre C. Effects of global warming on species with temperature-dependent sex determination: Bridging the gap between empirical research and management. Evol Appl 2021; 14:2361-2377. [PMID: 34745331 PMCID: PMC8549623 DOI: 10.1111/eva.13226] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/05/2021] [Accepted: 03/11/2021] [Indexed: 12/31/2022] Open
Abstract
Global warming could threaten over 400 species with temperature-dependent sex determination (TSD) worldwide, including all species of sea turtle. During embryonic development, rising temperatures might lead to the overproduction of one sex and, in turn, could bias populations' sex ratios to an extent that threatens their persistence. If climate change predictions are correct, and biased sex ratios reduce population viability, species with TSD may go rapidly extinct unless adaptive mechanisms, whether behavioural, physiological or molecular, exist to buffer these temperature-driven effects. Here, we summarize the discovery of the TSD phenomenon and its still elusive evolutionary significance. We then review the molecular pathways underpinning TSD in model species, along with the hormonal mechanisms that interact with temperatures to determine an individual's sex. To illustrate evolutionary mechanisms that can affect sex determination, we focus on sea turtle biology, discussing both the adaptive potential of this threatened TSD taxon, and the risks associated with conservation mismanagement.
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Affiliation(s)
- Emma C. Lockley
- School of Biological and Chemical SciencesQueen Mary University LondonLondonUK
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Chatting M, Hamza S, Al-Khayat J, Smyth D, Husrevoglu S, Marshall CD. Feminization of hawksbill turtle hatchlings in the twenty-first century at an important regional nesting aggregation. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01104] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Projected climate change is forecasted to have significant effects on biological systems worldwide. Marine turtles in particular may be vulnerable, as the sex of their offspring is determined by their incubating temperature, termed temperature-dependent sex determination. This study aimed to estimate historical, and forecast future, primary sex ratios of hawksbill turtle Eretmochelys imbricata hatchlings at an important nesting ground in northeastern Qatar. Incubation temperatures from the Arabian/Persian Gulf were measured over 2 nesting seasons. Climate data from same period were regressed with nest temperatures to estimate incubation temperatures and hatchling sex ratios for the site from 1993 to 2100. Future hatchling sex ratios were estimated for 2 climate forecasts, one mid-range (SSP245) and one extreme (SSP585). Historical climate data showed female-biased sex ratios of 73.2 ± 12.1% from 1993 to 2017. Female biases from 2018 to 2100 averaged 85.7% ± 6.7% under the mid-range scenario and 87.9% ± 5.4% under the high-range scenario. In addition, predicted female hatchling production was >90% from 2054 and 2052 for SSP245 and SSP585, respectively. These results show that hawksbill primary sex ratios in Qatar are at risk of significant feminization by the year 2100 and that hawksbill turtle incubation temperatures in an extreme, understudied environment are already comparable to those predicted in tropical rookeries during the latter half of the 21st century. These results can help conservationists predict primary sex ratios for hawksbill turtles in the region in the face of 21st-century climate change.
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Affiliation(s)
- M Chatting
- Environmental Science Center, Qatar University, Doha 2713, Qatar
| | - S Hamza
- Environmental Science Center, Qatar University, Doha 2713, Qatar
| | - J Al-Khayat
- Environmental Science Center, Qatar University, Doha 2713, Qatar
| | - D Smyth
- School of Ocean Sciences, Bangor University, Menai Bridge, Anglesey LL59 5EY, UK
| | - S Husrevoglu
- Institute of Marine Sciences, Middle East Technical University, Erdemli, Mersin 33731, Turkey
| | - CD Marshall
- Department of Marine Biology, Department of Wildlife and Fisheries Sciences, Gulf Center for Sea Turtle Research, Texas A&M University, Galveston, Texas 77553, USA
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Bentley BP, Stubbs JL, Whiting SD, Mitchell NJ. Variation in thermal traits describing sex determination and development in Western Australian sea turtle populations. Funct Ecol 2020. [DOI: 10.1111/1365-2435.13645] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Blair P. Bentley
- School of Biological Sciences The University of Western Australia Crawley WA Australia
| | - Jessica L. Stubbs
- School of Biological Sciences The University of Western Australia Crawley WA Australia
| | - Scott D. Whiting
- Marine Science Program Department of Biodiversity, Conservation and Attractions Kensington WA Australia
| | - Nicola J. Mitchell
- School of Biological Sciences The University of Western Australia Crawley WA Australia
- Oceans Institute The University of Western Australia Crawley WA Australia
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Wyneken J, Salmon M. Linking Ecology, Morphology, and Behavior to Conservation: Lessons Learned from Studies of Sea Turtles. Integr Comp Biol 2020; 60:440-455. [PMID: 32617553 DOI: 10.1093/icb/icaa044] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Here we describe examples of studies that have contributed both to a basic understanding of the biology of imperiled marine turtles, and to their management and conservation. Key elements include, first and foremost, correctly identifying species that differ strikingly in their morphology at different life stages because with growth, they change size by several orders of magnitude and have accompanying shape changes. We also review comprehensive field studies documenting the need for management actions to correct abnormal shifts in sex ratios caused by climate change. We highlight the need to describe those perturbations in terms that are clear to regulators and personnel responsible for management and conservation policies. Finally, we review several basic studies that enhance our understanding of how selection has shaped morphological, functional, and performance attributes, and describe how that knowledge can be applied to the tasks required for enhancing species recovery.
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Affiliation(s)
- Jeanette Wyneken
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991, USA
| | - Michael Salmon
- Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431-0991, USA
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Abstract
Climate change is occurring at an unprecedented rate and has begun to modify the distribution and phenology of organisms worldwide. Chelonians are expected to be particularly vulnerable due to limited dispersal capabilities as well as widespread temperature-dependent sex determination. The number of papers published about the effects of climate change on turtles has increased exponentially over the last decade; here, I review the data from peer-reviewed publications to assess the likely impacts of climate change on individuals, populations, and communities. Based upon these studies future research should focus on: (1) Individual responses to climate change, particularly with respect to thermal biology, phenology, and microhabitat selection; (2) improving species distribution models by incorporating fine-scale environmental variables as well as physiological processes; (3) identifying the consequences of skewed sex ratios; and (4) assessments of community resilience and the development of methods to mitigate climate change impacts. Although detailed management recommendations are not possible at this point, careful consideration should be given regarding how to manage low vagility species as habitats shift poleward. In the worst-case scenario, proactive management may be required in order to ensure that widespread losses do not occur.
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Valenzuela N, Literman R, Neuwald JL, Mizoguchi B, Iverson JB, Riley JL, Litzgus JD. Extreme thermal fluctuations from climate change unexpectedly accelerate demographic collapse of vertebrates with temperature-dependent sex determination. Sci Rep 2019; 9:4254. [PMID: 30862793 PMCID: PMC6414666 DOI: 10.1038/s41598-019-40597-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 02/20/2019] [Indexed: 01/08/2023] Open
Abstract
Global climate is warming rapidly, threatening vertebrates with temperature-dependent sex determination (TSD) by disrupting sex ratios and other traits. Less understood are the effects of increased thermal fluctuations predicted to accompany climate change. Greater fluctuations could accelerate feminization of species that produce females under warmer conditions (further endangering TSD animals), or counter it (reducing extinction risk). Here we use novel experiments exposing eggs of Painted Turtles (Chrysemys picta) to replicated profiles recorded in field nests plus mathematically-modified profiles of similar shape but wider oscillations, and develop a new mathematical model for analysis. We show that broadening fluctuations around naturally male-producing (cooler) profiles feminizes developing embryos, whereas embryos from warmer profiles remain female or die. This occurs presumably because wider oscillations around cooler profiles expose embryos to very low temperatures that inhibit development, and to feminizing temperatures where most embryogenesis accrues. Likewise, embryos incubated under broader fluctuations around warmer profiles experience mostly feminizing temperatures, some dangerously high (which increase mortality), and fewer colder values that are insufficient to induce male development. Therefore, as thermal fluctuations escalate with global warming, the feminization of TSD turtle populations could accelerate, facilitating extinction by demographic collapse. Aggressive global CO2 mitigation scenarios (RCP2.6) could prevent these risks, while intermediate actions (RCP4.5 and RCP6.0 scenarios) yield moderate feminization, highlighting the peril that insufficient reductions of greenhouse gas emissions pose for TSD taxa. If our findings are generalizable, TSD squamates, tuatara, and crocodilians that produce males at warmer temperatures could suffer accelerated masculinization, underscoring the broad taxonomic threats of climate change.
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Affiliation(s)
- Nicole Valenzuela
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.
| | - Robert Literman
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - Jennifer L Neuwald
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA.,Department of Biology, Colorado State University, Fort Collins, CO, 80523, USA
| | - Beatriz Mizoguchi
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - John B Iverson
- Department of Biology, Earlham College, Richmond, Indiana, 47374, USA
| | - Julia L Riley
- Department of Botany and Zoology, Stellenbosch University, Matieland, 7602, Stellenbosch, Western Cape, 7600, South Africa.,Department of Biology, Laurentian University, Sudbury, Ontario, P3E 2C6, Canada
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Montero N, dei Marcovaldi MAG, Lopez–Mendilaharsu M, Santos AS, Santos AJB, Fuentes MMPB. Warmer and wetter conditions will reduce offspring production of hawksbill turtles in Brazil under climate change. PLoS One 2018; 13:e0204188. [PMID: 30408043 PMCID: PMC6224045 DOI: 10.1371/journal.pone.0204188] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 10/18/2018] [Indexed: 01/27/2023] Open
Abstract
Climate change is expected to impact animals that are heavily reliant on environmental factors, such as sea turtles, since the incubation of their eggs, hatching success and sex ratio are influenced by the environment in which eggs incubate. As climate change progresses it is therefore important to understand how climatic conditions influence their reproductive output and the ramifications to population stability. Here, we examined the influences of five climatic variables (air temperature, accumulated and average precipitation, humidity, solar radiation, and wind speed) at different temporal scales on hawksbill sea turtle (Eretmochelys imbricata) hatchling production at ten nesting beaches within two regions of Brazil (five nesting beaches in Rio Grande do Norte and five in Bahia). Air temperature and accumulated precipitation were the main climatic drivers of hawksbill hatching success (number of eggs hatched within a nest) across Brazil and in Rio Grande do Norte, while air temperature and average precipitation were the main climatic drivers of hatching success at Bahia. Solar radiation was the main climatic driver of emergence success (number of hatchlings that emerged from total hatched eggs within a nest) at both regions. Warmer temperatures and higher solar radiation had negative effects on hatchling production, while wetter conditions had a positive effect. Conservative and extreme climate scenarios show air temperatures are projected to increase at this site, while precipitation projections vary between scenarios and regions throughout the 21st century. We predicted hatching success of undisturbed nests (no recorded depredation or storm-related impacts) will decrease in Brazil by 2100 as a result of how this population is influenced by local climate. This study shows the determining effects of different climate variables and their combinations on an important and critically endangered marine species.
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Affiliation(s)
- Natalie Montero
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida, United States of America
| | | | | | | | | | - Mariana M. P. B. Fuentes
- Department of Earth, Ocean, and Atmospheric Science, Florida State University, Tallahassee, Florida, United States of America
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Abstract
Thermal tolerances are affected by the range of temperatures that species encounter in their habitat. Daniel Janzen hypothesized in his “Why mountain passes are higher in the tropics” that temperature gradients were effective barriers to animal movements where climatic uniformity was high. Sea turtles bury their eggs providing some thermal stability that varies with depth. We assessed the relationship between thermal uniformity and thermal tolerance in nests of three species of sea turtles. We considered that barriers were “high” when small thermal changes had comparatively large effects and “low” when the effects were small. Mean temperature was lower and fluctuated less in species that dig deeper nests. Thermal barriers were comparatively “higher” in leatherback turtle (Dermochelys coriacea) nests, which were the deepest, as embryo mortality increased at lower “high” temperatures than in olive ridley (Lepidochelys olivacea) and green turtle (Chelonia mydas) nests. Sea turtles have temperature-dependent sex determination (TSD) and embryo mortality increased as temperature approached the upper end of the transitional range of temperatures (TRT) that produces both sexes (temperature producing 100% female offspring) in leatherback and olive ridley turtles. As thermal barriers are “higher” in some species than in others, the effects of climate warming on embryo mortality is likely to vary among sea turtles. Population resilience to climate warming may also depend on the balance between temperatures that produce female offspring and those that reduce embryo survival.
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Rees AF, Alfaro-Shigueto J, Barata PCR, Bjorndal KA, Bolten AB, Bourjea J, Broderick AC, Campbell LM, Cardona L, Carreras C, Casale P, Ceriani SA, Dutton PH, Eguchi T, Formia A, Fuentes MMPB, Fuller WJ, Girondot M, Godfrey MH, Hamann M, Hart KM, Hays GC, Hochscheid S, Kaska Y, Jensen MP, Mangel JC, Mortimer JA, Naro-Maciel E, Ng CKY, Nichols WJ, Phillott AD, Reina RD, Revuelta O, Schofield G, Seminoff JA, Shanker K, Tomás J, van de Merwe JP, Van Houtan KS, Vander Zanden HB, Wallace BP, Wedemeyer-Strombel KR, Work TM, Godley BJ. Are we working towards global research priorities for management and conservation of sea turtles? ENDANGER SPECIES RES 2016. [DOI: 10.3354/esr00801] [Citation(s) in RCA: 175] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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