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Anthropogenic and environmental stressors damage the structure and function of coral reefs. Monitoring data is important because it allows scientists to detect changes that are of interest for managers and policymakers. This study aims to examine the benthic component (abiotic and biotic) and determine coral life-history composition at different reef types (atoll and fringing) and regions (Wangi-Wangi and Kaledupa) in the Wakatobi National Park (WNP), Southeast Sulawesi, Indonesia. We examine the data using life-history traits in regard to group species and describe community composition. Kaledupa fringing reef had 46% hard coral cover, which was the highest hard coral cover in our study. There was no significant difference in hard coral and soft coral cover between regions within WNP. Reef type, however, showed significant differences in hard coral and soft coral cover, as well as sand, rubble, and rock. The families Acroporidae and Poritidae were the most dominant across all sites and reef types in WNP. The life-history classification showed competitive and stress-tolerant coral covers were greatest on fringing reefs. Our findings provide information regarding coral reef benthic community composition and distribution across regions and reef types in WNP, which can aid in coral reef conservation. [ABSTRACT FROM AUTHOR]

Many species have experienced recent range expansions due to human-mediated processes, such as the unintentional transport on ships or plastic waste and ocean warming, which facilitates many tropical species to tolerate living beyond their normal limit of distribution, with a potential impact on autochthonous assemblages. In September 2008, three colonies of the fire coral Millepora sp. (Cnidaria: Hydrozoa) were found on the southeastern coast of Tenerife (Canary Islands), though this species had been previously described to have a circumtropical distribution with Cape Verde Islands as its northern limit of distribution in the eastern Atlantic. The aim of this study was to determine the origin of these new colonies in the Canary Islands (11°N of its previously known northernmost limit of distribution) using variation in the cytochrome oxidase subunit I (COI) gene as a molecular marker. In order to do that, Millepora samples from Tenerife and Cape Verde Islands were collected for molecular analyses, and COI sequences from Caribbean samples listed in GenBank were also included in the analysis. Our results showed that all the specimens from Tenerife were genetically identical, suggesting that the colonization of the Canary Islands was the result of a very recent and strong founder effect. The nucleotide sequences of the samples from the Cape Verde and the Canary Islands were closer to the Caribbean than between themselves, pointing to the Caribbean population as the source population for both archipelagos, through independent founder events. The fact that Millepora sp. arrived to Cape Verde long before arriving to the Canaries (pleistocene fossils have been found in that archipelago) suggests that the habitat requirements for this species did not exist before in the Canarian archipelago. Therefore, the rising seawater temperatures recently registered in the Canary Islands could have facilitated the settlement of reef-forming corals drifting across the two basins of the Atlantic. [ABSTRACT FROM AUTHOR]

Efforts to map coral reef ecosystems in the Hawaiian Archipelago using optical imagery have revealed the presence of numerous scleractinian, zoothanthellate coral reefs at depths of 30–130+ m, most of which were previously undiscovered. Such coral reefs and their associated communities have been recently defined as mesophotic coral ecosystems (MCEs). Several types of MCEs are found in Hawai‘i, each of which dominates a different depth range and is characterized by a unique pattern of coral community structure and colony morphology. Although MCEs are documented near both ends of the archipelago and on many of the islands in between, the maximum depth and prevalence of MCEs in Hawai‘i were found to decline with increasing latitude. The Main Hawaiian Islands (MHI) had significantly deeper and greater percentages of scleractinian coral, and peaks in cover of both scleractinian corals and macroalgae occurred within depth bins 20 m deeper than in the Northwestern Hawaiian Islands (NWHI). Across the archipelago, as depth increased the combined percentage of living cover of mega benthic taxa declined sharply with increasing depth below 70 m, despite the widespread availability of hard substrate. [ABSTRACT FROM AUTHOR]