Global Conservation Priorities for Marine Turtles

Bryan P Wallace,Jeanne A Mortimer,Jeffrey A Seminoff,B C Choudhury,Raquel Briseño Dueñas,Roderic B Mast,Alexandre Girard,Brian W Bowen,Alan B Bolten,Karen A Bjorndal,Mark Hamann,Paolo Casale,Diego Amorocho,F Alberto Abreu-Grobois,Brian J Hutchinson,Brendan J Hurley,Elena M Finkbeiner,Alejandro Fallabrino,Jérôme Bourjea,Marc Girondot,Ronel Nel,John A Musick,Peter H Dutton,Maria Ângela Marcovaldi ,Alice Gabrielle De Sousa Costa ,Blair E Witherington ,Milani Chaloupka ,Milagros López‐Mendilaharsu ,Nicolas Pilcher ,Sebastián Troeng ,Andrew Dimatteo

doi:10.1371/journal.pone.0024510

Abstract

Where conservation resources are limited and conservation targets are diverse, robust yet flexible priority-setting frameworks are vital. Priority-setting is especially important for geographically widespread species with distinct populations subject to multiple threats that operate on different spatial and temporal scales. Marine turtles are widely distributed and exhibit intra-specific variations in population sizes and trends, as well as reproduction and morphology. However, current global extinction risk assessment frameworks do not assess conservation status of spatially and biologically distinct marine turtle Regional Management Units (RMUs), and thus do not capture variations in population trends, impacts of threats, or necessary conservation actions across individual populations. To address this issue, we developed a new assessment framework that allowed us to evaluate, compare and organize marine turtle RMUs according to status and threats criteria. Because conservation priorities can vary widely (i.e. from avoiding imminent extinction to maintaining long-term monitoring efforts) we developed a “conservation priorities portfolio” system using categories of paired risk and threats scores for all RMUs (n = 58). We performed these assessments and rankings globally, by species, by ocean basin, and by recognized geopolitical bodies to identify patterns in risk, threats, and data gaps at different scales. This process resulted in characterization of risk and threats to all marine turtle RMUs, including identification of the world's 11 most endangered marine turtle RMUs based on highest risk and threats scores. This system also highlighted important gaps in available information that is crucial for accurate conservation assessments. Overall, this priority-setting framework can provide guidance for research and conservation priorities at multiple relevant scales, and should serve as a model for conservation status assessments and priority-setting for widespread, long-lived taxa.

Highlights

Major challenges for conservation of widely distributed, longlived taxa are assessing conservation status at biologically appropriate scales and establishing conservation priorities based on those assessments [1,2,3]
The overall status and threats scores were used to plot all Regional Management Units (RMUs) on continua from low-to-high risk and low-to-high threats, which allowed for comparisons of conservation status among all RMUs, and both within and among species
We present results according to recognized MTSG regions, as well as by UN Food and Agriculture Organization (FAO)-recognized Regional Fisheries Bodies (RFBs) with management mandates, to determine patterns in risk, threats, and data needs according to relevant geographies and geopolitical bodies with potential to implement conservation strategies to address identified needs

Summary

Introduction

Major challenges for conservation of widely distributed, longlived taxa are assessing conservation status at biologically appropriate scales and establishing conservation priorities based on those assessments [1,2,3]. Current global extinction risk frameworks, most notably the IUCN Red List of Threatened SpeciesTM (www.iucnredlist.org), are not designed to capture and assess variation in status and trends of individual populations of wide-ranging species (e.g. sharks [4], marine turtles [5,6], marine mammals [7]). Assessing the status of and threats to distinct population segments or management units of these species are critical steps toward building sound frameworks for setting conservation priorities [3]. Marine turtle species are currently listed as Vulnerable (olive ridley, Lepidochelys olivacea), Endangered (loggerhead, Caretta caretta; green turtle, Chelonia mydas), Critically Endangered (Kemp’s ridley, Lepidochelys kempii; hawksbill, Eretmochelys imbricata; leatherback, Dermochelys coriacea), and Data Deficient (flatback, Natator depressus) on the Red List [8]. Threats to marine turtles vary across regions, but general categories include fisheries bycatch (i.e. incidental capture by marine fisheries operations targeting other species), take (e.g. utilization of eggs, meat or other turtle products), coastal development, pollution and pathogens, and climate change [9]

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Conclusion