A single conservation strategy for a widely distributed species works about as well as a one-size-fits-all pair of sweat pants — too loose for some people, uncomfortably tight for others.
A species may be listed as critically endangered while some populations within its ranks are thriving and some are probably beyond saving. With leatherback turtles, for example, tens of thousands of nesting females remain in the northwest Atlantic, yet their numbers in the eastern Pacific have dwindled by 90 percent in the last 20 years. From an official conservation standpoint, however, all leatherbacks are critically endangered.
A new report by the International Union for Conservation of Nature’s Marine Turtle Specialist Group, the world’s leading authority on sea turtles, establishes a novel framework for assessing the conservation status of populations so that accurate data can drive priorities and limited resources can be allocated more effectively.
“Everybody can make a case for why sea turtle conservation on their beach or in their waters or in their country is really important, and you can’t really refute it,” Bryan Wallace, the lead author on the paper, said in an interview. “Six of seven sea turtle species are vulnerable, endangered or critically endangered.”
“But resources are limited — managers’ attention spans and ability to make changes are limited,” he said. “We need to be able to provide context and justification for specific conservation strategies in specific areas.”
The framework described in the article, published in the journal PLos One, classifies sea turtle species in “regional management units.” Drawing on data from nearly 1,300 papers and reports and on the on-the-ground experience of over 30 experts, scientists calculated a risk and threat score for each management unit’s conservation status.
The risk score used five criteria to assess a population’s stability: current population size, recent trends in population size, long-term trends in population size, rookery vulnerability and genetic diversity.
The threat score quantified the relative danger posed by…