The status of hard coral communities at Kosrae, Micronesia

Abstract

Coral diversity is increasingly threatened by multiple 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 locality, 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 suggests the risk of regional diversity loss may be higher than expected. Ongoing coral reef monitoring and integrated watershed management to mitigate the threat of regional extinctions is needed.