1
|
Schofield G, Papafitsoros K, Chapman C, Shah A, Westover L, Dickson LC, Katselidis KA. More aggressive sea turtles win fights over foraging resources independent of body size and years of presence. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2022.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
|
2
|
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.
Collapse
|
3
|
Kahn JE, Watterson JC, Hager CH, Mathies N, Hartman KJ. Calculating adult sex ratios from observed breeding sex ratios for wide‐ranging, intermittently breeding species. Ecosphere 2021. [DOI: 10.1002/ecs2.3504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- J. E. Kahn
- National Marine Fisheries Service Silver Spring Maryland20910USA
| | - J. C. Watterson
- U.S. Department of the Navy Naval Facilities Engineering Command, Atlantic Norfolk Virginia23508USA
| | - C. H. Hager
- Chesapeake Scientific Williamsburg Virginia23185USA
| | - N. Mathies
- Chesapeake Scientific Williamsburg Virginia23185USA
| | - K. J. Hartman
- Division of Forestry and Natural Resources West Virginia University Morgantown West Virginia26506USA
| |
Collapse
|
4
|
Lee PLM, Schofield G, Haughey RI, Mazaris AD, Hays GC. A Review of Patterns of Multiple Paternity Across Sea Turtle Rookeries. ADVANCES IN MARINE BIOLOGY 2017; 79:1-31. [PMID: 30012274 DOI: 10.1016/bs.amb.2017.09.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Why females would mate with multiple partners and have multiple fathers for clutches or litters is a long-standing enigma. There is a broad dichotomy in hypotheses ranging from polyandry having benefits to simply being an unavoidable consequence of a high incidence of male-female encounters. If females simply give in to mating when it is too costly to avoid being harassed by males (convenience polyandry), then there should be a higher rate of mating as density increases. However, if females actively seek males because they benefit from multiple mating, then mating frequency, and consequently the incidence of multiple paternity of clutches, should be high throughout. To explore these competing explanations, here we review the incidence of multiple paternity for sea turtles nesting around the World. Across 30 rookeries, including all 7 species of sea turtle, the incidence of multiple paternity was only weakly linked to rookery size (r2=0.14). However, using high resolution at-sea GPS tracking we show that the specifics of movement patterns play a key role in driving packing density and hence the likely rate of male-female encounters. When individuals use the same focal areas, packing density could be 100× greater than when assuming individuals move independently. Once the extent of adult movements in the breeding season was considered so that movements and abundance could be combined to produce a measure of density, then across rookeries we found a very tight relationship (r2=0.96) between packing density and the incidence of multiple paternity. These findings suggest that multiple paternity in sea turtles may have no benefit, but is simply a consequence of the incidence of male-female encounters.
Collapse
Affiliation(s)
- Patricia L M Lee
- Centre for Integrative Ecology, Deakin University, Geelong, VIC, Australia
| | - Gail Schofield
- Centre for Integrative Ecology, Deakin University, Geelong, VIC, Australia
| | - Rebecca I Haughey
- Centre for Integrative Ecology, Deakin University, Geelong, VIC, Australia
| | - Antonios D Mazaris
- School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Graeme C Hays
- Centre for Integrative Ecology, Deakin University, Geelong, VIC, Australia.
| |
Collapse
|
5
|
Hart KM, Iverson AR, Benscoter AM, Fujisaki I, Cherkiss MS, Pollock C, Lundgren I, Hillis-Starr Z. Resident areas and migrations of female green turtles nesting at Buck Island Reef National Monument, St. Croix, US Virgin Islands. ENDANGER SPECIES RES 2017. [DOI: 10.3354/esr00793] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
6
|
Evans MN, Guerrero-Sanchez S, Bakar MSA, Kille P, Goossens B. First known satellite collaring of a viverrid species: preliminary performance and implications of GPS tracking Malay civets (Viverra tangalunga). Ecol Res 2016. [DOI: 10.1007/s11284-016-1338-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
7
|
Dunbar SG, Ito HE, Bahjri K, Dehom S, Salinas L. Recognition of juvenile hawksbills Eretmochelys imbricata through face scale digitization and automated searching. ENDANGER SPECIES RES 2014. [DOI: 10.3354/esr00637] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
8
|
Luschi P, Casale P. Movement patterns of marine turtles in the Mediterranean Sea: a review. ACTA ACUST UNITED AC 2014. [DOI: 10.1080/11250003.2014.963714] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
9
|
Hart KM, Lamont MM, Sartain AR, Fujisaki I, Stephens BS. Movements and habitat-use of loggerhead sea turtles in the northern Gulf of Mexico during the reproductive period. PLoS One 2013; 8:e66921. [PMID: 23843971 PMCID: PMC3700946 DOI: 10.1371/journal.pone.0066921] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 05/13/2013] [Indexed: 11/19/2022] Open
Abstract
Nesting strategies and use of important in-water habitats for far-ranging marine turtles can be determined using satellite telemetry. Because of a lack of information on habitat-use by marine turtles in the northern Gulf of Mexico, we used satellite transmitters in 2010 through 2012 to track movements of 39 adult female breeding loggerhead turtles (Caretta caretta) tagged on nesting beaches at three sites in Florida and Alabama. During the nesting season, recaptured turtles emerged to nest 1 to 5 times, with mean distance between emergences of 27.5 km; however, several turtles nested on beaches separated by ∼250 km within a single season. Mean total distances traveled throughout inter-nesting periods for all turtles was 1422.0±930.8 km. In-water inter-nesting sites, delineated using 50% kernel density estimation (KDE), were located a mean distance of 33.0 km from land, in water with mean depth of −31.6 m; other in-water inter-nesting sites, delineated using minimum convex polygon (MCP) approach, were located a mean 13.8 km from land and in water with a mean depth of −15.8 m. Mean size of in-water inter-nesting habitats were 61.9 km2 (50% KDEs, n = 10) and 741.4 km2 (MCPs, n = 30); these areas overlapped significantly with trawling and oil and gas extraction activities. Abundance estimates for this nesting subpopulation may be inaccurate in light of how much spread there is between nests of the same individual. Further, our results also have consequences for critical habitat designations for northern Gulf loggerheads, as protection of one nesting beach would not encompass the entire range used by turtles during breeding seasons.
Collapse
Affiliation(s)
- Kristen M Hart
- Southeast Ecological Science Center, U.S. Geological Survey, Davie, Florida, United States of America.
| | | | | | | | | |
Collapse
|
10
|
Snape RTE, Beton D, Broderick AC, Çiçek BA, Fuller WJ, Özden Ö, Godley BJ. Strand Monitoring and Anthropological Surveys Provide Insight into Marine Turtle Bycatch in Small-Scale Fisheries of the Eastern Mediterranean. CHELONIAN CONSERVATION AND BIOLOGY 2013. [DOI: 10.2744/ccb-1008.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
11
|
Schofield G, Dimadi A, Fossette S, Katselidis KA, Koutsoubas D, Lilley MKS, Luckman A, Pantis JD, Karagouni AD, Hays GC. Satellite tracking large numbers of individuals to infer population level dispersal and core areas for the protection of an endangered species. DIVERS DISTRIB 2013. [DOI: 10.1111/ddi.12077] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Affiliation(s)
- Gail Schofield
- Department of Biosciences; Swansea University; Singleton Park; Swansea; SA2 8PP; UK
| | - Alexandra Dimadi
- National Marine Park of Zakynthos; 1 El. Venizelou Str.; GR-29100; Zakynthos; Greece
| | | | | | | | | | - Adrian Luckman
- Department of Geography; Swansea University; Swansea; UK
| | - John D. Pantis
- Department of Ecology; School of Biology; Aristotle University of Thessaloniki; UP Box 119; 54006; Thessaloniki; Greece
| | - Amalia D. Karagouni
- Department of Botany; Faculty of Biology; Microbiology Group; National Kapodistrian University of Athens; Athens; 15781; Greece
| | | |
Collapse
|
12
|
Hoenner X, Whiting SD, Hindell MA, McMahon CR. Enhancing the use of Argos satellite data for home range and long distance migration studies of marine animals. PLoS One 2012; 7:e40713. [PMID: 22808241 PMCID: PMC3395646 DOI: 10.1371/journal.pone.0040713] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2012] [Accepted: 06/12/2012] [Indexed: 11/24/2022] Open
Abstract
Accurately quantifying animals’ spatial utilisation is critical for conservation, but has long remained an elusive goal due to technological impediments. The Argos telemetry system has been extensively used to remotely track marine animals, however location estimates are characterised by substantial spatial error. State-space models (SSM) constitute a robust statistical approach to refine Argos tracking data by accounting for observation errors and stochasticity in animal movement. Despite their wide use in ecology, few studies have thoroughly quantified the error associated with SSM predicted locations and no research has assessed their validity for describing animal movement behaviour. We compared home ranges and migratory pathways of seven hawksbill sea turtles (Eretmochelys imbricata) estimated from (a) highly accurate Fastloc GPS data and (b) locations computed using common Argos data analytical approaches. Argos 68th percentile error was <1 km for LC 1, 2, and 3 while markedly less accurate (>4 km) for LC ≤0. Argos error structure was highly longitudinally skewed and was, for all LC, adequately modelled by a Student’s t distribution. Both habitat use and migration routes were best recreated using SSM locations post-processed by re-adding good Argos positions (LC 1, 2 and 3) and filtering terrestrial points (mean distance to migratory tracks ± SD = 2.2±2.4 km; mean home range overlap and error ratio = 92.2% and 285.6 respectively). This parsimonious and objective statistical procedure however still markedly overestimated true home range sizes, especially for animals exhibiting restricted movements. Post-processing SSM locations nonetheless constitutes the best analytical technique for remotely sensed Argos tracking data and we therefore recommend using this approach to rework historical Argos datasets for better estimation of animal spatial utilisation for research and evidence-based conservation purposes.
Collapse
Affiliation(s)
- Xavier Hoenner
- Research Institute for Environment and Livelihoods, Charles Darwin University, Darwin, Northern Territory, Australia.
| | | | | | | |
Collapse
|
13
|
Hays GC, Fossette S, Katselidis KA, Schofield G, Gravenor MB. Breeding periodicity for male sea turtles, operational sex ratios, and implications in the face of climate change. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2010; 24:1636-1643. [PMID: 20497201 DOI: 10.1111/j.1523-1739.2010.01531.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Species that have temperature-dependent sex determination (TSD) often produce highly skewed offspring sex ratios contrary to long-standing theoretical predictions. This ecological enigma has provoked concern that climate change may induce the production of single-sex generations and hence lead to population extirpation. All species of sea turtles exhibit TSD, many are already endangered, and most already produce sex ratios skewed to the sex produced at warmer temperatures (females). We tracked male loggerhead turtles (Caretta caretta) from Zakynthos, Greece, throughout the entire interval between successive breeding seasons and identified individuals on their breeding grounds, using photoidentification, to determine breeding periodicity and operational sex ratios. Males returned to breed at least twice as frequently as females. We estimated that the hatchling sex ratio of 70:30 female to male for this rookery will translate into an overall operational sex ratio (OSR) (i.e., ratio of total number of males vs females breeding each year) of close to 50:50 female to male. We followed three male turtles for between 10 and 12 months during which time they all traveled back to the breeding grounds. Flipper tagging revealed the proportion of females returning to nest after intervals of 1, 2, 3, and 4 years were 0.21, 0.38, 0.29, and 0.12, respectively (mean interval 2.3 years). A further nine male turtles were tracked for short periods to determine their departure date from the breeding grounds. These departure dates were combined with a photoidentification data set of 165 individuals identified on in-water transect surveys at the start of the breeding season to develop a statistical model of the population dynamics. This model produced a maximum likelihood estimate that males visit the breeding site 2.6 times more often than females (95%CI 2.1, 3.1), which was consistent with the data from satellite tracking and flipper tagging. Increased frequency of male breeding will help ameliorate female-biased hatchling sex ratios. Combined with the ability of males to fertilize the eggs of many females and for females to store sperm to fertilize many clutches, our results imply that effects of climate change on the viability of sea turtle populations are likely to be less acute than previously suspected.
Collapse
Affiliation(s)
- Graeme C Hays
- Department of Pure and Applied Ecology, Institute of Environmental Sustainability, Swansea University, Singleton Park, Swansea SA2 8PP, UK.
| | | | | | | | | |
Collapse
|
14
|
Schofield G, Hobson VJ, Fossette S, Lilley MKS, Katselidis KA, Hays GC. BIODIVERSITY RESEARCH: Fidelity to foraging sites, consistency of migration routes and habitat modulation of home range by sea turtles. DIVERS DISTRIB 2010. [DOI: 10.1111/j.1472-4642.2010.00694.x] [Citation(s) in RCA: 152] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
|
15
|
Bell CD, Blumenthal JM, Broderick AC, Godley BJ. Investigating potential for depensation in marine turtles: how low can you go? CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2010; 24:226-235. [PMID: 19723137 DOI: 10.1111/j.1523-1739.2009.01313.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Where mechanisms inherent within the biology of a species affect individual fitness at low density, demographic-scale depensation may occur, hastening further decline and leading ultimately to population extirpation and species extinction. Reduction in fertility at low population densities has been identified in marine and terrestrial species. Using data on hatch success and hatchling-emergence success as proxies for fertilization success, we conducted a global meta-analysis of data from breeding aggregations of green turtles (Chelonia mydas) and loggerhead turtles (Caretta caretta). We found that there has been no reduction in fertility in small nesting aggregations in either of these species worldwide. We considered mechanisms within the mating strategies and reproductive biology of marine turtles that may allow for novel genetic input and facilitate enhanced gene flow among rookeries. Behavioral reproductive mechanisms, such as natal philopatry and polyandry, may mitigate potential impacts of depensation and contribute to the resilience of these species.
Collapse
Affiliation(s)
- C D Bell
- Marine Turtle Research Group, Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn TR10 9E2, United Kingdom
| | | | | | | |
Collapse
|