Coral reefs worldwide are degrading due to climate change, overfishing, pollution, coastal development, coral bleaching, and diseases. In areas where the natural recovery of an ecosystem is negligible or protection through management interventions insufficient, active restoration becomes critical. The Reef Futures symposium in 2018 brought together over 400 reef restoration experts, businesses, and civil organizations, and galvanized them to save coral reefs through restoration or identify alternative solutions. The symposium highlighted that solutions and discoveries from long-term and ongoing coral reef restoration projects in Spanish-speaking countries in the Caribbean and Eastern Tropical Pacific were not well known internationally. Therefore, a meeting of scientists and practitioners working in these locations was held to compile the data on the extent of coral reef restoration efforts, advances and challenges. Here, we present unpublished data from 12 coral reef restoration case studies from five Latin American countries, describe their motivations and techniques used, and provide estimates on total annual project cost per unit area of reef intervened, spatial extent as well as project duration. We found that most projects used direct transplantation, the coral gardening method, micro-fragmentation or larval propagation, and aimed to optimize or scale-up restoration approaches (51%) or provide alternative, sustainable

Coral reef decline persists as a global issue with ties to climate change and human footprint. The SeaFlower Biosphere reserve includes some of the most isolated oceanic coral reefs in the Southwestern Caribbean, which provide natural experiments to test global and/or basin-wide factors affecting coral reefs. In this study, we compared coral and other substrate cover (algae, cyanobacteria, and octocorals), along population densities of keystone urchin species from two atolls (Serrana and Roncador Banks), during 1995, 2003, and 2015/2016. We also surveyed benthic foraminifera as a water quality proxy for coral growth in the last period. A steady reduction in coral cover was clearly observed at Roncador's lagoon, but not at Serrana's reefs, with significant differences between 1995 and 2015/2016. Percent cover of fleshy algae decreased significantly also at Roncador between 1995 and 2003 but did not change notably from 1995 to 2016 at Serrana. However, both Banks exhibited a loss in crustose coralline algae from 2003 to 2015/2016. Likewise, a reduction in bottom complexity, measured as bottom rugosity, was evident between 1995 and 2003. Roncador Bank had unprecedented high octocoral densities, which increased almost threefold from 2003 to 2015. In contrast, urchin densities were low in Roncador; only Diadema antillarum increased from 2003 to 2016 in Serrana Bank. The Foraminifera in Reef Assessment and Monitoring (FORAM) Index (FI) in the two Banks was below the range expected for healthy coral reefs. Although both Banks follow a reduction in CCA and CA cover, Roncador Bank also faces an alarming decline in coral cover, urchins and bottom complexity (rugosity) in contrast to increases in octocoral densities and potential loss of resilience and eutrophication suggested by the FI index. These unexpected findings led us to consider and discuss potential outcomes, where these reefs deteriorate (i.e., erode and drown) providing ideal conditions for octocoral growth. Hence, it is of utmost urgency to start monitoring reef budgets, octocorals and nutrient sources.

39Coral reefs worldwide are degrading due to climate change, overfishing, pollution, coastal 40 development, bleaching and diseases. In areas where natural recovery is negligible or protection 41 through management interventions insufficient, active restoration becomes critical. The Reef Futures 42 symposium in 2018 brought together over 400 reef restoration experts, businesses, and civil 43 organizations, and galvanized them to save coral reefs through restoration or identify alternative 44 solutions. The symposium highlighted that solutions and discoveries from long-term and ongoing coral 45 reef restoration projects in Spanish-speaking countries in the Caribbean and Eastern Tropical Pacific 46were not well known internationally. Therefore, a meeting of scientists and practitioners working in 47 these locations was held to compile the data on the extent of coral reef restoration efforts, advances 48 and challenges. Here, we present unpublished data from 12 coral reef restoration case studies from 49five Latin American countries, describe their motivations and techniques used, and provide estimates 50 on total annual project cost per unit area of reef intervened, spatial extent as well as project duration. 51We found that most projects used direct transplantation, the coral gardening method, micro-52 fragmentation or larval propagation, and aimed to optimize or scale-up restoration approaches (51%) 53 or provide alternative, sustainable livelihood opportunities (15%) followed by promoting coral reef 54 conservation stewardship and re-establishing a self-sustaining, functioning reef ecosystem (both 55 13%). Reasons for restoring coral reefs were mainly biotic and experimental (both 42%), followed by 56 idealistic and pragmatic motivations (both 8%). The median annual total cost from all projects was 57 $93,000 USD (range: $10,000 USD -$331,802 USD) (2018 dollars) and intervened a median spatial 58 area of 1 ha (range: 0.06 ha -8.39 ha). The median project duration was 3 years; however, projects 59 have lasted up to 17 years. Project feasibility was high with a median of 0.7 (range: 0.5 -0.8). This 60 study closes the knowledge gap between academia and practitioners and overcomes the language 61 barrier by providing the first comprehensive compilation of data from ongoing coral reef restoration 62

Biodiversity on coral reefs depends not only on primary reef-builders, but also on associated taxa that create microhabitats for other species. Hydrocorals of the genus Stylaster, commonly known as lace corals, form small branching colonies that enhance three-dimensional complexity on reefs and are known to support a variety of commensal species. Furthermore, the genus is highly speciose, further increasing biodiversity. Despite their important ecological roles, little is known about the evolutionary history and the intraspecific diversity and structure in these broadly distributed hydrocorals. Here, we assessed the phylogenetic relationships among Atlantic species in the genus Stylaster and examined the genetic structure of S. roseus in the Tropical Western Atlantic (Caribbean and Brazil) and of S. blatteus in the Tropical Eastern Atlantic (Africa), using DNA sequences from the 16S ribosomal gene. Time-calibrated phylogenetic analyses showed that S. roseus and S. blatteus diverged at ~ 24.6 Ma. A well-supported Brazilian clade within S. roseus indicates a possible cryptic species that diverged at ~ 11.6 Ma, consistent with the formation of the Amazon River at 9 Ma (Hoorn et al. in Glob Planet Change 153:51–65, 2017). Strong genetic structure was observed even over moderate distances, with ΦST values over all populations being 0.98 for S. roseus and 0.90 for S. blatteus. Nearly, all haplotypes were private (found in a single location) and diverged by many mutational steps from one another. In contrast, genetic diversity was low at the local scale for both species, with most sites showing no variation (a single haplotype). These results are coherent with the reproductive strategy of Stylasteridae, where larvae are brooded and are highly developed at the time of release, often settling near the parental colony. Limited dispersal coupled with possible clonal reproduction have likely contributed to the high levels of genetic differentiation observed here. Lace corals show unusual reproductive and population dynamics compared to other reef inhabiting cnidarians. Future work may reveal additional cryptic diversity in this poorly studied family.