www.sciencemag.org SCIENCE VOL 342 15 NOVEMBER 2013 803 POLICYFORUM A lthough protected areas (PAs) cover 13% of Earth’s land ( 1), substan- tial gaps remain in their coverage of global biodiversity ( 2). Thus, there has been emphasis on strategic expansion of the global PA network ( 3– 5). However, because PAs are often understaffed, underfunded, and beleaguered in the face of external threats ( 6, 7), efforts to expand PA coverage should be complemented by appropriate management of existing PAs. Previous calls for enhancing PA management have focused on improving operational effectiveness of each PA [e.g., staffing and budgets ( 6)]. Little guidance has been offered on how to improve collec- tive effectiveness for meeting global biodi- versity conservation goals ( 3). We provide guidance for strategically allocating manage- ment efforts among and within existing PAs to strengthen their collective contribution toward preventing global species extinctions. Strategic Management Across PAs PAs vary in the extent to which they can con- tribute to preventing extinctions. The notion of “irreplaceability” reflects a site’s potential contribution to conservation goals or, con- versely, the extent to which options for meet- ing those goals are lost if the site is lost ( 4). Irreplaceability has been extensively used to identify potential new PAs [e.g., ( 2, 4)] but can also be applied to inform allocation of man- agement effort among existing sites ( 8). We highlight a set of exceptionally irreplaceable PAs for which we recommend a particularly high level of management effort and encour- age global recognition as World Heritage sites. We estimated the irreplaceability of each of the world’s 173,461 designated PAs, and of 2059 proposed sites ( 9), for ensuring rep- resentation of 21,419 vertebrate species, encompassing all amphibians, nonmarine mammals, and birds, of which 4329 are glob- ally threatened ( 10, 11) [see the supplemen- tary materials (SM)]. Irreplaceability was estimated from the fraction of the global dis- tribution of each species that is contained within each PA, by following a new approach that reduces the effect of the commission errors (falsely assuming species presence in PAs) inherent to the available spatial data (see SM). Irreplaceability scores and rela- tive ranks were obtained both when consid- ering all species (overall irreplaceability) or only those species that are globally at risk of extinction (threatened species irreplace- ability), for all taxa combined (multitaxa), as well as separately for each taxonomic group (amphibians, mammals, and birds) (table S1). We highlight a subset of 137 PAs, covering 1.7 million km 2 , identified by combining the 100 highest-ranking sites in terms of overall irreplaceability with the 100 most irreplace- able areas for threatened species (see the figure, fig. S1, and table S2). Mainly located in tropical forest regions, particularly in mountains and on islands, these highly irreplaceable PAs encompass a wide diversity of other ecosystems. PA sizes range from 41 to 364,793 km 2 (table S2). Nearly all are located in biogeographic regions of exceptional levels of endemism ( 12) and nearly all have already been iden- tified as key biodiversity areas ( 13). Collec- tively, they are responsible for the long-term conservation prospects of 627 species (119 birds, 385 amphibians, and 123 mammals), including 304 globally threatened species (60 birds, 179 amphibians, and 65 mam- mals) whose global distributions fall mostly (>50%) within these sites. For 88 of these PAs, the conservation stakes are particularly high, as they overlap sites previously iden- tified as holding ≥95% of the global popu- lation of at least one highly threatened spe- cies, where species extinctions are immi- nent unless effective conservation action is implemented ( 14). The United Nations World Heritage Convention (WHC) seeks to encourage the identification and conservation of natural and cultural heritage of “outstanding uni- versal value.” Among currently designated World Heritage Sites (WHS), 132 have been inscribed [under criterion (x)] as having out- standing universal value for the in situ con- servation of biodiversity (see SM) ( 15). Their very high overall irreplaceability (91% are among the 95th percentile of PA irreplace- ability for all species and/or for threatened species examined here) (table S1) suggests a remarkable agreement between outstanding universal value, as defined by the WHC, and Protected Areas and Effective Biodiversity Conservation CONSERVATION Soizic Le Saout, 1 Michael Hoffmann, 2,3 Yichuan Shi, 2,3 Adrian Hughes, 2 Cyril Bernard, 1 Thomas M. Brooks, 2,4 Bastian Bertzky, 3 * Stuart H. M. Butchart, 5 Simon N. Stuart, 2,3,6,7,8 Tim Badman, 2 Ana S. L. Rodrigues 1 † Increasing the collective contribution of protected areas toward preventing species extinctions requires the strategic allocation of management efforts. *Present address: European Commission, Joint Research Centre, Institute for Environment and Sustainability, Ispra, Italy. †Corresponding author. E-mail: ana.rodrigues@cefe.cnrs.fr 1 Centre d’Ecologie Fonctionnelle et Evolutive, CEFE-CNRS UMR5175, 34293 Montpellier, France. 2 International Union for Conservation of Nature, CH-1196 Gland, Switzerland. 3 United Nations Environment Programme World Conserva- tion Monitoring Centre, Cambridge CB3 0DL, UK. 4 School of Geography and Environmental Studies, University of Tas- mania, Hobart, Tasmania 7001, Australia. 5 BirdLife Interna- tional, Cambridge CB3 0NA, UK. 6 Conservation International, Arlington, VA, 22202, USA. 7 Department of Biology and Bio- chemistry, University of Bath, Bath BA2 7AY, UK. 8 Al Ain Zoo, Abu Dhabi, United Arab Emirates. The Bale Mountains National Park in the Ethiopian highlands is home more than half of the world’s esti- mated 366 Ethiopian wolves, Canis simensis ( 10) seen at right. CREDITS (LEFT TO RIGHT) LONELY PLANET IMAGES/GETTY IMAGES; ANUP SHAH/GETTY IMAGES Published by AAAS on April 24, 2014 www.sciencemag.org Downloaded from on April 24, 2014 www.sciencemag.org Downloaded from on April 24, 2014 www.sciencemag.org Downloaded from