1
|
Redding OT, Castorani MCN, Lasala J. The effects of dune plant roots on loggerhead turtle ( Caretta caretta) nest success. Ecol Evol 2024; 14:e11207. [PMID: 38571807 PMCID: PMC10985360 DOI: 10.1002/ece3.11207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 03/03/2024] [Accepted: 03/15/2024] [Indexed: 04/05/2024] Open
Abstract
Sand dunes are supported by the extensive root systems of dune plants that anchor the dune and protect it from erosion. While all plants that grow on the dunes support their structure, invasive plants can outcompete the native and non-native dune plants for resources such as nutrients, sunlight, and space to grow. During the summer, sea turtles lay nests on beaches and near dunes; however, their eggs and hatchlings are at risk of destruction and entrapment by dune plant root penetration. Dune plant roots can penetrate sea turtle nest cavities, thus decreasing hatch success of the eggs and emergence success of the hatchlings. We aimed to determine how plant roots impact threatened loggerhead sea turtle (Caretta caretta) nests on Casey Key, Sarasota County, Florida, USA and to assess the factors affecting plant root invasion. Specifically, we determined the effect of plant roots on loggerhead sea turtle nest success, the extent of the impact of invasive plants over non-invasive plants on nests, and if the distance from the dune (barrier) affects whether roots will penetrate the nest. From July to August 2022, we excavated 93 nests to determine the extent of root penetration and identify associated plant species. This field campaign was supported by a long-term dataset (1987-2022) on loggerhead sea turtle nesting across the region. We found that root presence decreased hatch success by 21% and emergence success by 18%, compared to nests that lacked roots within the nest chamber. Nests closer to the dune were more likely to have a higher proportion of root damage and lower hatch and emergence success. This study helps advance understanding of how native and non-native plants affect sea turtle reproductive success and helps inform coastal management aimed at conserving threatened loggerhead populations.
Collapse
Affiliation(s)
- Olivia T. Redding
- Department of Environmental SciencesUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Max C. N. Castorani
- Department of Environmental SciencesUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Jake Lasala
- Sea Turtle Conservation and Research ProgramMote Marine LaboratorySarasotaFloridaUSA
| |
Collapse
|
2
|
Staines MN, Versace H, Laloë JO, Smith CE, Madden Hof CA, Booth DT, Tibbetts IR, Hays GC. Short-term resilience to climate-induced temperature increases for equatorial sea turtle populations. GLOBAL CHANGE BIOLOGY 2023; 29:6546-6557. [PMID: 37795641 DOI: 10.1111/gcb.16952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/28/2023] [Accepted: 09/06/2023] [Indexed: 10/06/2023]
Abstract
Projection models are being increasingly used to manage threatened taxa by estimating their responses to climate change. Sea turtles are particularly susceptible to climate change as they have temperature-dependent sex determination and increased sand temperatures on nesting beaches could result in the 'feminisation' of hatchling sex ratios for some populations. This study modelled likely long-term trends in sand temperatures and hatchling sex ratios at an equatorial nesting site for endangered green turtles (Chelonia mydas) and critically endangered hawksbill turtles (Eretmochelys imbricata). A total of 1078 days of sand temperature data were collected from 28 logger deployments at nest depth between 2018 and 2022 in Papua New Guinea (PNG). Long-term trends in sand temperature were generated from a model using air temperature as an environmental proxy. The influence of rainfall and seasonal variation on sand temperature was also investigated. Between 1960 and 2019, we estimated that sand temperature increased by ~0.6°C and the average hatchling sex ratio was relatively balanced (46.2% female, SD = 10.7). No trends were observed in historical rainfall anomalies and projections indicated no further changes to rainfall until 2100. Therefore, the sex ratio models were unlikely to be influenced by changing rainfall patterns. A relatively balanced sex ratio such as this is starkly different to the extremely female-skewed hatchling sex ratio (>99% female) reported for another Coral Sea nesting site, Raine Island (~850 km West). This PNG nesting site is likely rare in the global context, as it is less threatened by climate-induced feminisation. Although there is no current need for 'cooling' interventions, the mean projected sex ratios for 2020-2100 were estimated 76%-87% female, so future interventions may be required to increase male production. Our use of long-term sand temperature and rainfall trends has advanced our understanding of climate change impacts on sea turtles.
Collapse
Affiliation(s)
- Melissa N Staines
- School of the Environment, The University of Queensland, St. Lucia, Queensland, Australia
| | - Hayley Versace
- Conflict Islands Conservation Initiative, Alotau, Milne Bay Province, Papua New Guinea
| | - Jacques-Olivier Laloë
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
| | - Caitlin E Smith
- World Wide Fund for Nature-Australia, Brisbane, Queensland, Australia
- School of Science, Technology and Engineering, University of the Sunshine Coast, Queensland, Hervey Bay, Australia
| | | | - David T Booth
- School of the Environment, The University of Queensland, St. Lucia, Queensland, Australia
| | - Ian R Tibbetts
- School of the Environment, The University of Queensland, St. Lucia, Queensland, Australia
| | - Graeme C Hays
- School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
| |
Collapse
|
3
|
Charles KE, Morrall CE, Edwards JJ, Carter KD, Afema JA, Butler BP, Marancik DP. Environmental and Nesting Variables Associated with Atlantic Leatherback Sea Turtle ( Dermochelys coriacea) Embryonic and Hatching Success Rates in Grenada, West Indies. Animals (Basel) 2023; 13:ani13040685. [PMID: 36830474 PMCID: PMC9951857 DOI: 10.3390/ani13040685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 01/20/2023] [Accepted: 02/02/2023] [Indexed: 02/18/2023] Open
Abstract
Annual monitoring of leatherback sea turtle (Dermochelys coriacea) nesting grounds in Grenada, West Indies has identified relatively low hatch rates compared to worldwide trends. This study investigated the impact of selected environmental variables on leatherback sea turtle embryonic development and hatching success rates on Levera Beach in Grenada between 2015-2019. The mean number of nests per year and eggs per nest were 667.6 ± 361.6 and 80.7 ± 23.0 sd, respectively. Within excavated nests, 35.6% ± 22.0 sd of eggs successfully developed embryos and 30.6% ± 22.6 sd of eggs successfully hatched. The number of eggs per nest, along with embryo and hatching success rates, differed by nesting year. Embryo development success rate was associated with nest location, and both embryo development and hatching success rates were positively associated with nest depth and negatively associated with the percentage of eggs exhibiting microbial growth and with the presence of inspissated yolk. There was no embryo development or hatchling success association with month of the nesting season, distance from the high-water mark, distance from vegetation, nor maternal carapace length. The mean nest temperature was 31.7 °C ± 1.64 sd and mean temperatures during the middle third of egg incubation suggest clutches are highly skewed towards a preponderance of female hatchlings. Histopathologic findings in hatchling mortalities included severe, acute, multifocal, heterophilic bronchopneumonia with intralesional bacteria in 4/50 (8%) hatchlings. Data from this study guide conservation strategies by identifying risk factors and further avenues of research needed to support reproductive success of leatherback sea turtles in Grenada and the greater Caribbean region.
Collapse
Affiliation(s)
- Kate E. Charles
- Department of Pathobiology, School of Veterinary Medicine, St. George’s University, True Blue, West Indies, Grenada
- Ocean Spirits, Inc., West Indies, Grenada
- Correspondence: ; Tel.: +1473-537-2512
| | - Clare E. Morrall
- Ocean Spirits, Inc., West Indies, Grenada
- Department of Biology, Ecology, and Conservation, School of Arts and Sciences, St. George’s University, True Blue, West Indies, Grenada
| | - Jonnel J. Edwards
- Department of Pathobiology, School of Veterinary Medicine, St. George’s University, True Blue, West Indies, Grenada
| | - Kenrith D. Carter
- Ocean Spirits, Inc., West Indies, Grenada
- Dr Carter Veterinary Services, West Indies, Grenada
| | - Josephine A. Afema
- Department of Pathobiology, School of Veterinary Medicine, St. George’s University, True Blue, West Indies, Grenada
| | - Brian P. Butler
- Department of Pathobiology, School of Veterinary Medicine, St. George’s University, True Blue, West Indies, Grenada
| | - David P. Marancik
- Department of Pathobiology, School of Veterinary Medicine, St. George’s University, True Blue, West Indies, Grenada
| |
Collapse
|
4
|
Potential impacts of sea level rise and beach flooding on reproduction of sea turtles. CLIMATE CHANGE ECOLOGY 2022. [DOI: 10.1016/j.ecochg.2022.100053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
5
|
Gatto CR, Reina RD. A review of the effects of incubation conditions on hatchling phenotypes in non-squamate reptiles. J Comp Physiol B 2022; 192:207-233. [PMID: 35142902 PMCID: PMC8894305 DOI: 10.1007/s00360-021-01415-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 09/15/2021] [Accepted: 10/03/2021] [Indexed: 11/28/2022]
Abstract
Developing embryos of oviparous reptiles show substantial plasticity in their responses to environmental conditions during incubation, which can include altered sex ratios, morphology, locomotor performance and hatching success. While recent research and reviews have focused on temperature during incubation, emerging evidence suggests other environmental variables are also important in determining hatchling phenotypes. Understanding how the external environment influences development is important for species management and requires identifying how environmental variables exert their effects individually, and how they interact to affect developing embryos. To address this knowledge gap, we review the literature on phenotypic responses in oviparous non-squamate (i.e., turtles, crocodilians and tuataras) reptile hatchlings to temperature, moisture, oxygen concentration and salinity. We examine how these variables influence one another and consider how changes in each variable alters incubation conditions and thus, hatchling phenotypes. We explore how incubation conditions drive variation in hatchling phenotypes and influence adult populations. Finally, we highlight knowledge gaps and suggest future research directions.
Collapse
Affiliation(s)
- Christopher R Gatto
- School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, VIC, 3800, Australia.
| | - Richard D Reina
- School of Biological Sciences, Monash University, 25 Rainforest Walk, Clayton, VIC, 3800, Australia
| |
Collapse
|
6
|
Guerra CC, Ricardo JA, Ávila RB, Bretos F, Álvarez PP. Influence of Sandy Coast Vegetation on the Reproductive Success of Green Turtles at Cuban Nesting Beaches. CHELONIAN CONSERVATION AND BIOLOGY 2021. [DOI: 10.2744/ccb-1460.1] [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)
| | - Julia Azanza Ricardo
- Instituto Superior de Tecnología y Ciencias Aplicadas, Universidad de La Habana, La Habana 10400, Cuba []
| | | | - Fernando Bretos
- The Ocean Foundation, 1320 19th Street NW, 5th Floor, Washington, DC 20036 USA []
| | - Pedro Pérez Álvarez
- Instituto Superior de Tecnología y Ciencias Aplicadas, Universidad de La Habana, La Habana 10400, Cuba []
| |
Collapse
|
7
|
Kang CQ, Meng QY, Dang W, Lu HL. Divergent incubation temperature effects on thermal sensitivity of hatchling performance in two different latitudinal populations of an invasive turtle. J Therm Biol 2021; 100:103079. [PMID: 34503815 DOI: 10.1016/j.jtherbio.2021.103079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/05/2021] [Accepted: 08/12/2021] [Indexed: 11/19/2022]
Abstract
The incubation temperature for embryonic development affects several aspects of hatchling performance, but its impact on the thermal sensitivity of performance attributes remains poorly investigated. In the present study, Trachemys scripta elegans hatchlings from two different latitudinal populations were collected to assess the effects of different incubation temperatures on the locomotor (swimming speed) and physiological (heart rate) performances, and the thermal sensitivity of these two attributes. The incubation temperature significantly affected the examined physiological traits. Hatchling turtles produced at low incubation temperature exhibited relatively higher cold tolerance (lower body temperatures at which the animals lose the ability to escape from the lethal conditions), and reduced heart rate and swimming speed. Furthermore, the effect of incubation temperature on the thermal sensitivity of swimming speed differed between the low- and high-latitude populations. At relatively high incubation temperatures, the high-latitude hatchling turtles exhibited reduced thermal sensitivities of swimming speed than those of the low-latitude ones. Reduced thermal sensitivity of locomotor performance together with high cold tolerance, exhibited by the high-latitude hatchling turtles potentially reflected local adaptation to relatively colder and more thermally-variable environments.
Collapse
Affiliation(s)
- Chun-Quan Kang
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Qin-Yuan Meng
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Wei Dang
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Hong-Liang Lu
- Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, School of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China.
| |
Collapse
|
8
|
Porter E, Booth DT, Limpus CJ, Staines MN, Smith CE. Influence of short-term temperature drops on sex-determination in sea turtles. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2021; 335:649-658. [PMID: 34313387 DOI: 10.1002/jez.2509] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 06/30/2021] [Accepted: 07/09/2021] [Indexed: 11/08/2022]
Abstract
All sea turtles exhibit temperature-dependent sex-determination, where warmer temperatures produce mostly females and cooler temperatures produce mostly males. As global temperatures continue to rise, sea turtle sex-ratios are expected to become increasingly female-biased, threatening the long-term viability of many populations. Nest temperatures are dependent on sand temperature, and heavy rainfall events reduce sand temperatures for a brief period. However, it is unknown whether these short-term temperature drops are large and long enough to produce male hatchlings. To discover if short-term temperature drops within the sex-determining period can lead to male hatchling production, we exposed green and loggerhead turtle eggs to short-term temperature drops conducted in constant temperature rooms. We dropped incubation temperature at four different times during the sex-determining period for a duration of either 3 or 7 days to mimic short-term drops in temperature caused by heavy rainfall in nature. Some male hatchlings were produced when exposed to temperature drops for as little as 3 days, but the majority of male production occurred when eggs were exposed to 7 days of lowered temperature. More male hatchlings were produced when the temperature drop occurred during the middle of the sex-determining period in green turtles, and the beginning and end of the sex-determining period in loggerhead turtles. Inter-clutch variation was evident in the proportion of male hatchlings produced, indicating that maternal and or genetic factors influence male hatchling production. Our findings have management implications for the long-term preservation of sea turtles on beaches that exhibit strongly female-biased hatchling sex-ratios.
Collapse
Affiliation(s)
- Ellen Porter
- School of Biological Sciences, Faculty of Science, The University of Queensland, Brisbane, Queensland, Australia
| | - David T Booth
- School of Biological Sciences, Faculty of Science, The University of Queensland, Brisbane, Queensland, Australia
| | - Colin J Limpus
- Queensland Government Department of Science and Environment, Aquatic Threatened Species Unit, Brisbane, Queensland, Australia
| | - Melissa N Staines
- School of Biological Sciences, Faculty of Science, The University of Queensland, Brisbane, Queensland, Australia
| | - Caitlin E Smith
- Brisbane Office, World Wildlife Fund Australia, Brisbane, Australia
| |
Collapse
|
9
|
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 []
| |
Collapse
|
10
|
Gaviria-Hernández J, Páez VP, Ramírez DM, Ceballos CP. Embryo Development and Sex Ratios in the Red-Footed Tortoise (Chelonoidis carbonarius) at Masculinizing Temperatures. CHELONIAN CONSERVATION AND BIOLOGY 2021. [DOI: 10.2744/ccb-1441.1] [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)
- Juliana Gaviria-Hernández
- Grupo GAMMA, Escuela de Medicina Veterinaria, Facultad de Ciencias Agrarias, Universidad de Antioquia, Calle 70 N° 52-21, Medellín, Colombia [; ]
| | - Vivian P. Páez
- Grupo Herpetológico de Antioquia, Instituto de Biología, Universidad de Antioquia, Calle 70 N° 52-21, Medellín, Colombia []
| | - Diber M. Ramírez
- Centro de Atención y Valoración del Área Metropolitana del Valle de Aburrá, Medellín, Colombia []
| | - Claudia P. Ceballos
- Grupo GAMMA, Escuela de Medicina Veterinaria, Facultad de Ciencias Agrarias, Universidad de Antioquia, Calle 70 N° 52-21, Medellín, Colombia [; ]
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Mazlan NA, Booth DT, Rusli MU. Testing the validity of using raceway and swimway performance in sea turtle hatchlings as an index of real-life crawling and swimming performance. WILDLIFE RESEARCH 2021. [DOI: 10.1071/wr21029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
13
|
Santidrián Tomillo P, Spotila JR. Temperature-Dependent Sex Determination in Sea Turtles in the Context of Climate Change: Uncovering the Adaptive Significance. Bioessays 2020; 42:e2000146. [PMID: 32896903 DOI: 10.1002/bies.202000146] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 07/22/2020] [Indexed: 11/11/2022]
Abstract
The adaptive significance of temperature-dependent sex determination (TSD) in reptiles remains unknown decades after TSD was first identified in this group. Concurrently, there is growing concern about the effect that rising temperatures may have on species with TSD, potentially producing extremely biased sex ratios or offspring of only one sex. The current state-of the-art in TSD research on sea turtles is reviewed here and, against current paradigm, it is proposed that TSD provides an advantage under warming climates. By means of coadaptation between early survival and sex ratios, sea turtles are able to maintain populations. When offspring survival declines at high temperatures, the sex that increases future fecundity (females) is produced, increasing resilience to climate warming. TSD could have helped reptiles to survive mass extinctions in the past via this model. Flaws in research on sex determination in sea turtles are also identified and it is suggested that the development of new techniques will revolutionize the field.
Collapse
Affiliation(s)
| | - James R Spotila
- Department of Biodiversity, Earth and Environmental Science, Drexel University, Philadelphia, Pennsylvania, 19104, USA
| |
Collapse
|