Assessment Frameworks

Although several other frameworks assess marine turtle status at global and sub-global scales, in this chapter we focus on results from the International Union for the Conservation of Nature (IUCN) Red List assessments and the IUCN Marine Turtle Specialist Group's conservation priorities portfolio (Wallace et al., 2011) because these are the most comprehensive and widely recognized assessment frameworks at present. For a comprehensive summary of other assessment frameworks for marine turtles, please see Chapter 35. In this chapter, we provide an overview of the two above-mentioned IUCN assessments with regard to marine turtles, and we also present available information on the conservation status of sea snakes and marine iguanas.

Status Assessments

IUCN Red List

The primary global assessment framework for marine turtle species is the IUCN Red List of Threatened SpeciesTM (www.iucnredlist.org). The universally applicable criteria and guidelines of the Red List make it the most widely used and accepted framework for assessing the conservation status of species worldwide.

The IUCN Marine Turtle Specialist Group (MTSG), one of the IUCN/ Species Survival Commission's specialist groups, is responsible for conducting regular Red List assessments of each marine turtle species on a global scale. However, because marine turtle population traits and trajectories can vary geographically, the global extinction risk assessment framework represented by the Red List does not adequately assess the conservation status of spatially and biologically distinct marine turtle populations (see Seminoff and Shanker, 2008 for review).

Subpopulation or regional assessments

To address the challenges presented by the mismatched scales of global Red List assessments and regional/population-level variation in status, the MTSG developed an alternative assessment framework and a new approach to Red List assessments that better characterize variation in status and trends of individual populations (Wallace et al., 2010; Wallace et al., 2011; see next section). This new approach centres on assessing marine turtle subpopulations, as well as the global population (i.e., species), using Red List guidelines, which results in official Red List categories for subpopulations in addition to the single global listing. This working group first developed regional management units (RMUs) (i.e., spatially explicit population segments defined by biogeographical data of marine turtle species) as the framework for defining biologically meaningful population segments for assessments (Wallace et al., 2010). RMUs are functionally equivalent to IUCN subpopulations, thus providing the appropriate demographic unit for Red List assessments.