Status of the pillar coral Dendrogyra cylindrus in Los Roques National Park, Southern Caribbean

Abstract

Information on the status of the pillar coral Dendrogyra cylindrus across its global distribution range is needed to plan and implement effective conservation interventions at both the national and regional level. Knowledge on the species distribution and abundance on the southernmost edge of its range was limited to qualitative data gathered in the 1980s. In 2014, we started using local ecological knowledge and extensive surveys to assess the status of the pillar coral in Archipelago Los Roques National Park, Venezuela; also evaluating the species representativeness within the MPA according to the level of protection established by the parks zoning. Between 2014 and 2016, we recorded over 1,000 colonies-the highest abundance reported to date for the species- within 14 different habitat types. Disease, bleaching and partial mortality prevalence were below 4%. Size frequency distribution was uni-modal for the MPA and dominated by medium size colonies (40cm -70cm height) suggesting potential for intrinsic population growth. However, the structure of size classes varied among reefs (Pseudo-F=2.70, p=0.03), indicating asynchronous dynamics mostly driven by reef-scale processes. Overall, our results indicate that Los Roques could be a stronghold for the species. But, to maintain the conservation value for coral reefs and the pillar coral, the MPAs zoning designation needs to be urgently revised and the extension of its high-protection zones expanded to increase habitat redundancy as well as the singular habitats composed by thickets of Acropora cervicornis and mounds of Madracis sp. This work confirms the species as extant in one of the four localities within its national range in Venezuela. However, further research on genetic diversity and connectivity among reefs within the MPA is needed to estimate effective population size and assess viability.