Phenological response of sea turtles to environmental variation across a species' northern range

Understanding the at-sea spatial behaviour of sea turtles is a priority for their conservation. In the present paper, the current information on the distribution and movement patterns of the two species breeding in the Mediterranean, the loggerhead and the green turtle, is reviewed, focusing mainly on the 195 published routes of satellite-tracked turtles. A satisfactory level of knowledge about adults' migrations and other movements is reached only for loggerheads breeding at Zakynthos Island, Greece, and for green and loggerhead females nesting in Cyprus, while studies at foraging grounds are limited to loggerheads in the western and central parts of the basin. Adult males and females mostly show quite uniform post-breeding migratory patterns, typically moving towards individually specific neritic foraging grounds. A much higher variability is shown by loggerhead juveniles, which is probably associated with differences in their spatial behaviour while in oceanic or neritic waters. Evidence of seasonal migrations driven by lower temperatures in winter is available only for adult and juvenile loggerheads frequenting the two northernmost parts of the basin, i.e. the Ligurian and the northern Adriatic Sea. Current knowledge gaps and priorities for further research in the Mediterranean are discussed.

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“…timing of prebreeding migrations) might be flexible and controlled by the environment (e.g. by sea temperatures; Mazaris et al 2013). …”

Section: Adult Loggerhead Turtlesmentioning

confidence: 99%

Movement patterns of marine turtles in the Mediterranean Sea: a review

Luschi

Casale

2014

Italian Journal of Zoology

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“…Such shifts in nesting phenology are relatively slow compared to other sea turtle species at higher-latitude nesting beaches (e.g. Weishampel et al 2004, Pike et al 2006, Mazaris et al 2013. Moreover, the shift observed at Playa Grande is the first time a shift for nesting later in the year has been reported for any sea turtle population.…”

Section: Discussionmentioning

confidence: 82%

“…The factors governing nesting phenology have only been investigated for only 2 sea turtle species: loggerhead turtles Caretta caretta (Weishampel et al 2004, Pike et al 2006, Mazaris et al 2013) and green turtles Chelonia mydas (Pike 2009, Weishampel et al 2010, Dalleau et al 2012. For both species, it has been repeatedly shown that the timing of the nesting season is influenced by the sea surface temperature of the waters near the nesting grounds (e.g.…”

Section: Introductionmentioning

confidence: 99%

Multidecadal trends in the nesting phenology of Pacific and Atlantic leatherback turtles are associated with population demography

Robinson¹,

Valentine²,

Tomillo³

et al. 2014

Endang. Species. Res.

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Knowledge of the mechanisms influencing phenology can provide insights into the adaptability of species to climate change. Here, we investigated the factors influencing multidecadal trends in the nesting phenology of the leatherback turtle Dermochelys coriacea at Playa Grande, Costa Rica, in the eastern Pacific Ocean and at Sandy Point, US Virgin Islands, in the western Atlantic Ocean. Between 1993 and 2013, the median nesting date (MND) at Playa Grande occurred later, at a rate of ~0.3 d yr . The opposing trends in the MND of each population were not explained by variation in the multivariate El Niño-Southern Oscillation index, North Atlantic Oscillation index, or Atlantic Multidecadal Oscillation index; however, the MND at Playa Grande was significantly correlated with nesting population size. We propose that changes in demography, linked to the population decline at Playa Grande, and the population recovery at Sandy Point may explain the contrasting trends in MNDs. If the observed trends in MND continue into the future, the nesting season at Playa Grande will coincide with increasingly adverse conditions for hatching success, exacerbating the already detrimental effects of climate change. Alternatively, shifts in the nesting phenology may make the Atlantic populations more resilient to climate change. Our findings highlight the increasing need for conservation efforts for eastern Pacific leatherback turtles to consider climate change mitigation practices.

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“…También se ha mostrado que el clima en algunas ocasiones tiene influencia a esta escala, tanto en la ocurrencia de la temporada de reproducción como en el inicio, duración y fin a la anidación de las tortugas (Mazaris et al 2013, Neeman et al 2015, Álvarez-Acosta 2016.…”

Section: Escala Espacial Mediaunclassified

Spatial and temporal dimensions of the critical habitat selection processes by sea turtles

Cuevas¹

2019

Rev. biol. mar. oceanogr.

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Abstract.-Marine turtles are large vertebrates with a complex life cycle along which they occupy several habitats in their different stages. This complexity imposes challenges for the study and knowledge of their populations, and for decades numerous studies have targeted to understand the factors that determine the selection and use of the resources they require at their different stages. The inclusion of the spatial and temporal scales in the conception of the research efforts is of the highest transcendence to obtain robust and pertinent information about the habitat selection processes. The objective of this revision was to analyze different scales and approaches used to evaluate the selection processes of nesting beaches, nesting sites and feeding habitats by sea turtles, considering some of the biological, ecological and evolutive implications linked to these processes. Based on the available literature, some of the reported results are analyzed in terms of their implications for conservation and management of their populations and the critical habitats they occupy. The study of the processes involved in the selection and use of the critical habitats that sea turtles occupy is nowadays an active, pertinent and of highest relevance; fact that reassert the strategic and fundamental importance of long time monitoring studies, as the only way to evaluate in a convincing way alterations of their populations and habitats at different spatial and temporal scales. Key words:Resources use, habitat selection, spatial scale, temporal scaleResumen.-Las tortugas marinas son especies de grandes vertebrados que tienen un ciclo de vida complejo en el que ocupan diversos hábitats durante sus distintos estadios de vida. Tal complejidad impone retos para el estudio y conocimiento de sus poblaciones, y por décadas numerosas investigaciones se han dedicado a entender los factores que determinan la selección y uso de los recursos que requieren en sus diferentes etapas. La concepción a una escala espacial y temporal de los esfuerzos de investigación es de suma trascendencia para obtener información robusta y pertinente sobre los procesos de selección de sus hábitats. El objetivo de esta revisión fue analizar diferentes escalas y aproximaciones abordadas pa ra la evaluación de los procesos de selección de playas de anidación, sitios de anidación y hábitats de alimentación por las tortugas marinas, considerando algunas de las implicaciones biológicas, ecológicas y evolutivas asociadas a dichos procesos. A partir de resultados publicados se analizan algunos de los resultados reportados y las implicaciones que estos procesos t ienen en temas de conservación y manejo de sus poblaciones y hábitats críticos. El estudio de los procesos de selección y uso de los hábitats críticos que ocupan las tortugas marinas es una línea actualmente vigente, pertinente y de alta relevancia, a través de la cual se reitera la importancia estratégica y fundamental de estudios de monitoreo a largo plazo, única manera de evaluar de forma contundente modifi...

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Phenological response of sea turtles to environmental variation across a species' northern range

Cited by 59 publications

References 55 publications

Movement patterns of marine turtles in the Mediterranean Sea: a review

Movement patterns of marine turtles in the Mediterranean Sea: a review

Multidecadal trends in the nesting phenology of Pacific and Atlantic leatherback turtles are associated with population demography

Spatial and temporal dimensions of the critical habitat selection processes by sea turtles

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