ORIGINAL PAPER The status of hard coral communities at Kosrae, Micronesia Zoe Richards Received: 16 June 2014 /Revised: 18 August 2014 /Accepted: 20 August 2014 # Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg 2014 Abstract Coral diversity is increasingly threatened by multi- ple anthropogenic and climate stressors. Threatened species assessments play an important role in guiding conservation action for management and mitigation of losses, but to provide accurate assessments it is necessary to collect quantitative data at an appropriate scale. When assessed at a global scale the level of threat facing corals in the tropical western Pacific Ocean is perceived to be low. However, whether the global threat classifications reflect the needs of species at regional scales remains to be verified. Here the status of scleractinian coral diversity is explored at a little-known Micronesian lo- cality, Kosrae (5°15’S 162°58 E). Sixteen percent of the species recorded on the current survey are classified as Vulnerable on a global scale; however, down-scaling the assessment suggests that a larger proportion of species (up to 25%) may be vulnerable to regional extinction because they occupy a low proportion of sites. Twelve species are classified as Vulnerable at global and regional scales, and further monitoring of threatened species is needed to verify the status of 53 species that are listed as Data Deficient in the region. Despite the lower level of perceived extinction risk to coral communities in the NW Pacific, this study sug- gests the risk of regional diversity loss may be higher than expected. Ongoing coral reef monitoring and integrated wa- tershed management to mitigate the threat of regional extinc- tions is needed. Keywords Beta diversity . Biodiversity . Local abundance and occupancy patterns . Near-pristine . Threatened species . Scleractinia . Succession Introduction Coral reefs are globally significant but are also seriously threatened repositories of marine biodiversity (Jackson et al. 2001; Harvell et al. 2002; Pandolfi et al. 2003); hence, there is a growing impetus to forecast, detect and mitigate the effects of stressors on coral reef biodiversity (Hughes et al. 2003). Securing the health and resilience of coral reef ecosystems is imperative, not only because of their diversity and unique geological structure (Kleypas et al. 2001), but also because of their socio-economic value (Moberg and Folke 1999). Scleractinian corals are critical components of the coral reef ecosystem, providing the structural framework of reefs and contributing to primary production and nutrient recycling, along with providing microhabitat and food for a wide diver- sity of coral reef species (Stella et al. 2011; Hoeksema et al. 2012). With 231 species of scleractinian coral now included on the Red List of Threatened Species (Carpenter et al. 2008), further targeted species-specific studies are needed to monitor the fate of corals and the success of conservation action. Coral reef communities on isolated Pacific islands and atolls are often considered to host a low proportion of threat- ened species because they are removed from large-scale an- thropogenic threats and have relatively stable ocean climates (Carpenter et al. 2008; Burke et al. 2011; Burrows et al. 2011). On the contrary, however, isolated atolls and small islands are among the most economically, socially and ecologically vul- nerable places on Earth (Thaman 2008) because island people depend almost entirely upon their biodiversity for economic and cultural survival. Furthermore, while Pacific Island coral reefs may be remote from large urban centres, they are by no Electronic supplementary material The online version of this article (doi:10.1007/s12526-014-0266-8) contains supplementary material, which is available to authorized users. Z. Richards (*) Department of Aquatic Zoology, Western Australian Museum, 49 Kew Street, Welshpool, WA 6105, Australia e-mail: zoe.richards@museum.wa.gov.au Mar Biodiv DOI 10.1007/s12526-014-0266-8