Regional Management Units

Compilation

Regional Management Units (RMUs) are geographically explicit population segments based on geographic boundaries to distributions derived from studies on genetics, tag returns, satellite telemetry, and other data. RMUs were meant to encompass multiple nesting sites, mtDNA-defined nesting populations, and nDNA-defined breeding populations to reflect shared geographic distribution among conspecific marine turtles in the same region. Thus, RMUs do not represent complete geographic distributions of species on global or regional scales, but rather distributions that are anchored to landmasses by known nesting site(s) and/or genetic stock origins and defined by biogeographical information.

These RMUs were generated using the citations listed below and refined by regional experts. In cases where an RMU spans an ocean basin, the sites anchoring the RMU can be determined by the name of the RMU, e.g. the West Atlantic RMUs are anchored by sites on the east coast of North and South America and the Wider Caribbean. For a full list of attributes associated with each RMU please download the associated metadata. If you have information that could improve or refine these distributions, please use the feedback button to provide as much of this information as possible. Any suggested changes must be accompanied by relevant citations to be accepted and incorporated. Feedback will be reviewed and used to update these distributions periodically.

Citations

Full citations are available in an EndNote library.
The library is also included in the zipped file of the layer shapefiles.

Distribution map

Compilation

Global distributions were generated using the citations listed below and refined by regional experts. These global distributions are coarse geographical representations of documented occurrence patterns – bounded by maximum extents – for each species. If you have information that could improve or refine these distributions, please use the feedback button to provide as much of this information as possible. Any suggested changes must be accompanied by relevant citations to be accepted and incorporated. Feedback will be reviewed and used to update these distributions periodically.

Citations

Caretta caretta - Loggerhead


Chelonia mydas - Green


Dermochelys coriacea - Leatherback


Eretmochelys imbricata - Hawksbill


Lepidochelys kempii - Kemp's ridley


Lepidochelys olivacea - Olive ridley


Natator depressus - Flatback

mtDNA

Compilation

These layers were generated by compiling locations from published and gray literature where nesting colonies were sampled for mtDNA studies. We accepted genetic stock definitions as described by the original sources, rather than attempting to standardize or prioritize methodologies or interpretations. For a full list of attributes associated with each site please download the associated metadata. If you have information on additional sampled sites, please use the feedback button to provide as much of this information as possible. Any suggested changes must be accompanied by relevant citations to be accepted and incorporated. Feedback will be reviewed and used to update these distributions periodically.

Citations

Full citations are available in an EndNote library.
The library is also included in the zipped file of the layer shapefiles.

nDNA

Compilation

These layers were generated by compiling locations from published and gray literature where nesting colonies were sampled for nDNA studies. We accepted genetic stock definitions as described by the original sources, rather than attempting to standardize or prioritize methodologies or interpretations. For a full list of attributes associated with each site please download the associated metadata. If you have information on additional sampled sites, please use the feedback button to provide as much of this information as possible. Any suggested changes must be accompanied by relevant citations to be accepted and incorporated. Feedback will be reviewed and used to update these distributions periodically.

Citations

Full citations are available in an EndNote library.
The library is also included in the zipped file of the layer shapefiles.

Global Habitat Suitability

Abstract

Aim: To understand whether climate limits current sea turtle nesting distributions and shapes the ecological niche of the terrestrial life history stage of these wide-ranging marine vertebrates.

Methods: I predicted the spatial distributions of nesting habitat under current climatic conditions for seven sea turtle species using information criteria and Maximum entropy modelling. I also compared niche similarity among species using three niche metrics: I, Schoener’s D, and relative rank.

Results: Sea turtles currently nest across their entire bioclimatic envelopes, with up to six species predicted to nest on a single beach. The Caribbean Sea, Gulf of Mexico, and Australasia support high nesting diversity, with most regional areas supporting three to five species. Despite large overlap in nesting distributions among species, loggerhead and green turtles have the broadest environmental niches, while Kemp’s ridley and flatback turtles have very narrow niches.

Main conclusions: The terrestrial nesting habitat of sea turtles is characterized by distinct climatic conditions, which are linked to the physical conditions necessary for eggs to hatch successfully and allow hatchlings to disperse from natal areas. Despite broad geographic patterns of overlap and similar embryonic tolerances to temperature and moisture among species, sea turtles partition habitat by nesting in different niche space. The tight link between current geographic patterns of nesting and climate, along with the dependence of developing embryos on nest microclimate, imply that regional or global changes in environmental conditions could differentially influence the distribution of sea turtle species under climate change. This could influence the adaptive potential of different populations, and predicted these responses before they occur will be important in mitigating the effects of climate change.


Legend

 

Color Habitat quality metrics
Marginal marginal
Moderate moderate
Good good
Excellent excellent

Citations

Pike, D.A. 2013. Climate influences the global distribution of sea turtle nesting. Global Ecology and Biogeography, in press.

A PDF of the cited paper is included in the zipped file of the downloaded shapefiles.