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What are the most threatened turtles in the world?

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The Hawksbill turtle is one of the most threatened species on the planet.
The Hawksbill turtle is one of the most threatened species on the planet.

By Stacey Venzel

An increasing number of threats face the Testudines family resulting in more species becoming threatened each year. As an example, six of the seven species of sea turtles are threatened with extinction.

Globally, turtles can be classified according to the International Union for Conservation of Nature (IUCN) census, labeled in increasing order of concern as vulnerable, endangered, critically endangered or extinct in the wild, as well as data deficient.

IUCN RED LIST

The IUCN is the most highly regarded organization for classifying the conservation status—also referred to as the red list status—for flora and fauna. Continuously adjusted, significant assessment changes are reported as new data surfaces. Individual countries and continents have their own regional categorical standards that could reflect a different level of concern geographically, such as regulations set by the National Oceanic and Atmospheric Association (NOAA) and U.S. Fish and Wildlife Service (USFWS). Threatened species are grouped as vulnerable, endangered or critically endangered.

VULNERABLE

As of December 2013, approximately 60 species are listed as vulnerable to extinction, equating to around 18 percent of the global turtle population of the modern day (defined as after 1500 AD). Two examples of vulnerable species listed by the IUCN are the Yellow-footed tortoise and olive ridley sea turtle. The leatherback sea turtle is listed as vulnerable on a global scale but some subpopulations are critically endangered.

ENDANGERED

About 15 percent of turtles are endangered, the IUCN’s Tortoise and Freshwater Turtle Specialist Group (TFTSG) has 50 species on the list. Dahl’s toad-headed turtle was listed as one of the most critically endangered chelonians at the turn of the century but was downgraded to endangered after the population count increased with unearthed hidden habitats. Loggerhead and green sea turtles fall under this red list status.

CRITICALLY ENDANGERED

Around 17 to 18 percent of turtles are critically endangered with 57 species categorized accordingly. Globally, Kemp’s ridley and hawksbill sea turtles fall into this group along with the bog turtle and Southern river terrapin. Species in this category are nearest extinction, often with only a few individuals left in the wild.

EXTINCT IN THE WILD

Eight species are found to be extinct in the wild, totaling approximately 2 percent of the turtle population. These are solely giant tortoises, excluding the Seychelles mud turtle determined to be extinct around the year 1950. The black softshell turtle, also called the Bostami softshell, was previously thought to be extinct in the wild according to the 2002 IUCN census. However, a 2011 report has the species rediscovered yet listed as critically endangered.

DATA DEFICIENT

Some species lack sufficient research to reach a conclusive red list status, classifying them simply as data deficient. Ten to 11 percent of turtles are included here, about 35 species, including the flatback sea turtle of Australia and New Guinea waters, a few mud turtle species and the Asian leaf turtle.

CONCLUSIONS

Collectively, an estimated 50 to 58 percent of the recognized modern members of the Testudines family are threatened. This make them one of the major vertebrate groups closest to extinction according to the IUCN, far exceeding birds, mammals, bony fish and even amphibians. Turtles outlived the dinosaurs, their ancestry tracing back to 245 million years ago, but species alive in the 21st century face problems unknown to their ancient lineage, causes most notably linked to humans.

Sources:

T Blanck, BD Horne, R Hudson, Et. Al., “Turtles in trouble:The world’s 25+ most endangered tortoises and freshwater turtles—2011,” MTC Printing, Inc., February 2011. http://cmsdata.iucn.org/downloads/top_25__turtles_in_trouble_2011_1.pdf

Roger Bour, John B Iverson, Anders GJ Rhodin, Et. Al., “Turtles of the world, 7th edition: Annotated checklist of taxonomy, synonymy, distribution with maps, and conservation status,” Chelonian Research Foundation, June 16, 2014, https://www.eeb.ucla.edu/Faculty/Shaffer/pubs/TTWG_Checklist_2014.pdf.

Carl J Franklin, Turtles: An Extraordinary Natural History 245 Million Years in the Making (St. Paul, Voyageur Press, 2007), 9.

Whit Gibbons, Judy Greene, Turtle: The Animal Answer Guide (Baltimore, The John Hopkins University Press, 2009), 99-100.

M Girondot, M Tiwari, BP Wallace, “Dermochelys coriacea. The IUCN Red List of Threatened Species 2013,” International Union for Conservation of Nature and Natural Resources, 2013, http://www.iucnredlist.org/details/6494/0.

 
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